Quarter 3 LESSON: Produce Vegetables Module 5: Maintain the growth of vegetable crops 1. 2. 3. 4. 5.
Apply recommended kind and rate of fertilizers Perform irrigation and drainage practices Practice weeding and cultivation Control of insect pests and diseases Perform mulching Content Standard
The
learner
demonstrates
Performance Standard
The
learner
independently
applies the recommended kind
understanding on the application
and
of recommended kind and rate
accordance with FPA Guidelines
of fertilizers.
and policies.
Lesson 5
rate
of
fertilizers
in
Maintain the growth of vegetable crops
Introduction
This module deals with the knowledge, skills, and attitudes in maintaining the growth of plants. It includes the application of fertilizers, perform irrigation and drainage, practice weeding and cultivation, control insect pests and diseases, and perform mulching. Learning Competencies/Objectives
This module has the following learning competencies/objectives: 1. Apply recommended kind and rate of fertilizers 2. Perform irrigation and drainage practice 3. Practice weeding and cultivation 4. Control of insect pests and diseases 5. Perform mulching
PRE-/DIAGNOSTIC ASSESSMENT Direction:
Read and understand the questions carefully and select the best answer by writing the LETTER in your test notebook. 1.
Plants need food to nourish their parts. Which of the following refers to any organic or inorganic materials of natural or synthetic origin which is added to the soil to suppy certain elemens essential for plant growth? a. Fertilizer b. Trace elements c. Macroelements d. Microelements 2. The amount of fertilizer to be applied applied depends on many factors. Whih of the following is the least observed factor regarding rate of fertilizer application? a. Nutrinet requirement of the plant b. The manner of appluying the fertilizer c. Environmental factors particularly rainfall d. The capability of the farmer to supply the neededfertilizer 3. Which of the following methods of fertilizer application is most applicable ito seedlings to have have their starter solution applied? a. Fertigation b. Broadcasting c. Foliar applicationd d. Localized application 4. There are several ways ways of determining soil fertility which are simple and complicated. This method observes any abnormal appearance of the growing plant plant which maybe caused by a deficiency of one or more nutrient elements. a. Soil analysis b. Plant tissue analysis c. Field fertilizer trials d. nutrient deficiency symptom 5. Which one is the primary function of nitrogen? a. Hastens maturity b. Aids in seed formation c. Forms and transfers starch d. Gives dark green color to plant 6. When the fertilizers are applied in scattered manner over the surface of the land, the method of fertilization is a. side dressing b. broadcasting c. foliar application d. band or row or localized placements 7. Which of the following is NOT a method of determining soil fertility? a. soil analysis b. field fertilizer trials c. nutrient deficiency symptom d. foliar application of fertilizer
PRE-/DIAGNOSTIC ASSESSMENT Direction:
Read and understand the questions carefully and select the best answer by writing the LETTER in your test notebook. 1.
Plants need food to nourish their parts. Which of the following refers to any organic or inorganic materials of natural or synthetic origin which is added to the soil to suppy certain elemens essential for plant growth? a. Fertilizer b. Trace elements c. Macroelements d. Microelements 2. The amount of fertilizer to be applied applied depends on many factors. Whih of the following is the least observed factor regarding rate of fertilizer application? a. Nutrinet requirement of the plant b. The manner of appluying the fertilizer c. Environmental factors particularly rainfall d. The capability of the farmer to supply the neededfertilizer 3. Which of the following methods of fertilizer application is most applicable ito seedlings to have have their starter solution applied? a. Fertigation b. Broadcasting c. Foliar applicationd d. Localized application 4. There are several ways ways of determining soil fertility which are simple and complicated. This method observes any abnormal appearance of the growing plant plant which maybe caused by a deficiency of one or more nutrient elements. a. Soil analysis b. Plant tissue analysis c. Field fertilizer trials d. nutrient deficiency symptom 5. Which one is the primary function of nitrogen? a. Hastens maturity b. Aids in seed formation c. Forms and transfers starch d. Gives dark green color to plant 6. When the fertilizers are applied in scattered manner over the surface of the land, the method of fertilization is a. side dressing b. broadcasting c. foliar application d. band or row or localized placements 7. Which of the following is NOT a method of determining soil fertility? a. soil analysis b. field fertilizer trials c. nutrient deficiency symptom d. foliar application of fertilizer
8. In order to conserve soil fertility, the following methods should be practiced EXCEPT a. composting, b. application of organic fertilizer c. practice cover cropping and mulching d. practice green manuring and intercropping 9. Water in an important requirement in growing plants. The supply of water to the soil by any other means than rainfall is a. Irrigation b. Irrigation by hand c. Irrigation by wind mill d. Irrigation by power machinery 10. This method of irrigation is used to apply water with the use of sprinklers to irrigate crops grown in a small piece of land like school and home gardens. a. irrigation by hand b. irrigation by windmill c. irrigation by gravity d. irrigation by power machinery 11. Which of the following is not a good reason for removing or controlling the weeds? a. weeds increase land value. b. weeds cause a decrease in crop production c. weeds increase labor cost and cost of production. d. weeds harbor plant pests which may affect plant growth and yield. 12. Which of the following is NOT a mechanical method of controlling weeds. a. burning b.cutting c. cover cropping d. uprooting the weeds. 13. Which of these methods of controlling weeds is NOT environmentally friendly? a. biological b. chemical c. mechanical d. cropping and competition 14. Which is NOT true about cultivation? a. It destroys weeds. b. It conserves soil moisture. c. It improves soil aeration. d. It decreases crop yield. 15. The best time to cultivate is a after draining the field b. after watering or irrigating c. upon the appearance of weeds d. . after planting and before the crop covers the ground. 16. Pests in any form are the farmers’ enemy and may cause enormous damage to their crops. What do you call that pest which is a small invertebrate animal having three pairs of legs, three body divisions, and usually with wings. a. bees b. insects c. butterfies d. cut worms
What to Know Activity 1 Living things have life to maintain. Men, animals, and plants need a lot of things in order to live. These three living things have symbiotic relationships. The absence of one may make life miserable. The manner on how to maintain lives of men, animals, and plants differ from each other. Let us find out how they live. This time group yourselves into 4 for the following topics to discuss. Again, draw your topic. Discuss among yourselves, summarize your ideas and present to class your output. Group 1 – 1 – How How do men maintain a healthful life? Group 2 – 2 – How How do animals live? Group 3 – 3 – How How do plants complete their cycle? Group 4 - Give the symbiotic relationships of men, animals, and plants.
Apply Recommended Kind and Rate of Fertilizers Plant food Growing plants like animals, require food for growth and development. This food is composed of certain chemical elements often referred to as plant-food elements. Table 7. Table of plant food elements and their functions (Malcolm H. Mcvickar (1970)
Plant Nutrient
Chemical
Functions
Symbol
Macro-Elements Nitrogen
N
Promotes dark green color; leaf, stem, and fruit development; and hastens growth and increase the protein content of the crop.
Phosphorous P 2O5
favors rapid plant growth and development; hastens fruiting and maturity; and improves the quality of the crop.
Potasium
K2O
Hastens maturity; Stimulates blooming; aids in seed formation; and gives plants hardiness
Micro-Elements Micro-Element s
Calcium
Ca
Corrects acidity; acts as protective sieve for the nitrates to sep through in passing into the cells; and acts as a cement between the alls of he cells to hold them together
Magnesium
Mg
The
key
element
in
the
molecule
of
chlorophyll, and Mg combines with the phosphates so that the latte can move to their proper places in the plant.
Sulfur
S
Gives green color to the younger leaves including the veins
Manganese
Mn
Gives green color to the younger leaves including the veins
Boron The
B
trace
Boron hunger results to a reddish-yellow discoloration and often therenis purplish
elements
tone, first seen on the margins of the leaves or the tip half.
Copper
Cu
Helps in seedstalk formation
Zinc
Zn
Treats abnormally small leaves, yellow or mottled in appearance
Iron
Fe
Treats chlorosis
Molybdenum
Mo
Influences the utilization of nitrogen by the plant and it is requiredbefore nitrogen-fixing bacteria cn utilize atmospheric nitrogen
Chlorine
Cl
Tends to concentrate in some plants, in the veins and floral parts and appears to be tied up in some way in the formation of the red, blue, and violet pigments Hastens maturity and
Plant food refers to the necessary materials wherein a plant can build new tissues and at the same time carry on its normal functions According to Mcvickar Mcvickar (1970) fertilizer fertilizer is any manufactured manufactured or processed processed material or mixture of materials that contains one or more of the recognized plant-food elements, either in liquid or dry form.
On the other hand, authors of the Resource Manual in IPPM in Vegetable (2005) claimed that a fertilizer is any organic or inorganic material of natural or synthetic origin which is added to the soil to supply certain elements essential to plant growth. Fertilizers are used to increase the growth rate, yield and quality or nutritive value of plants. The Manual explained further that for many decades in the past, the term fertilizers practically meant commercial fertilizers of nonliving origin. In recent years, however, increasing attention has been focused on organic and bio-fertilizers which are biological sources of plant nutrients. The proper usage of fertilizers requires knowledge not only of their properties but also of their effects on soil. The amount of fertilizer to be applied depends on many factors which include the nutrient requirement of the plants, the ability of the soil to supply nutrients, yield potential, other management practices, the capability of the farmer and other environmental factors particularly rainfall.
Kinds of fertilizers
1. Organic fertilizers are farm manures, compost, crop residues, and other farm wastes which supply nutrients and improve soil physical conditions. Organic fertilizer is generally the most valuable soil conditioner.. As soil conditioners, organic fertilizer helps prevent soil erosion, crushing and cracking of soil. They retain soil humidity and improve the internal drainage of the soil. These fertilizers should serve as supplement to inorganic fertilizers. It improves the physical make-up of the soil making it porous and rich in organic matter explained by Sangatan and Sangatan (2000) Again Sangatan and Sangatan organic fertilizer as follows:
(2000) enumerated the sources of
Animal wastes: cattle , carabao, pig, goat, poultry, horse manure, urine, and etc. Crop wastes: rice straw, corn stalks, weeds, stuubles, leaves ofplants, husks, etc. Human inhabitation wastes: night soil, sewage, garbage Green manure: ipil-ipil leaves, legumes, madre se cacao leaves. Water crop or plants: water hyacinth (water lily) water alligator, water lettuce. Biological organic sources: azolla, blue green akgae Silt, river mud, pond mud By-product of biogas digester, digested sludge and effluent Other sources: animal bone, ash, seaweeds, guano (bat manure)
2. Inorganic (chemical) fertilizers usually result from chemical processes such as sulfuric acid treatment or rock phosphate to produce superphosphate. It consists of materials processed or transformed into a chemical material or fertilizer.
Single element fertilizer contains only one of the major fertilizer elements. Examples: Ammonium sulfate, urea, superphosphate Incomplete fertilizer contains only two major elements like ammophos (nitrogen and phosphorus) Complete fertilizers contain the three primary plant food elements: nitrogen, phosphorus and potassium
Table 8. Analysis of Common Inorganic or Commercial Fertilizers Percent Material
N
P2O5
K2O
Anhydrous ammonia
82
0
0
Ammonium sulfate
21
0
0
Ammonium phosphate
16
20
0
Ammonium chloride
25
0
0
Urea
46
0
0
Superphosphate
0
20
0
Trial superphosphate
0
48
0
Muriate of potash
0
0
60
Sulfate of potash
0
0
50
Complete
14
14
14
Fertilizer Computation To supply a certain amount of plant nutrients, determine the amount of fertilizer to be applied per hectare based on the composition of the fertilizer materials to be used. Here are some examples on how to determine the amount of fertilizer. Nitural (Undated) defined fertilizer grade or analysis refers to the minimum guarantee of the nutrient content in terms of percent total N, percent available P 2O5 , and percent water soluble K 20 in a fertilizer. For example, the fertilizer grade of ammonium sulfate contains 21 kgs available N but it does not contain P2O5 and K2O. the remaining 79 kgs represents the materials termed as ”carriers” or “fillers”. A mixed complete fertilizer with a grade of 12-24-12 contains 12%N, 24% available P 2O5 and 12% K2O. The fertilizer recommendation is expressed in kilograms N, kilograms P2O5 and kilograms K 2O per hectare, respectively. In technical publications, this is written as, for example, 90-60-30. This recommendation involves the application of 90 kgsN, 60 kgs P 2O5 and 30 kgs K 2O5 per hectare, respectively.
To calculate the weight of fertilizer, divide the weight of the nutrient from the recommendation by the nutrient content of the fertilizer material (from the grade or analysis). Thus: (1)
Weight of fertilizer =
weight of the nutrient %
nutrient
X 100
To get the number of fertilizer bags, divide the weight of nutrients required by the weight of the nutrients per bag, thus: (2) Number of fertilizer bag =
Weight of nutrient weihgt of nutrient per bag
Or, divide the weight of fertilizer from formula (1) by the weight per bag, thus, Number of fertilizer bag =
Weight of fertilizer Weight per bag
Sample Computations: 5.1.1.1. Recommended rate: 90-60-30 Available Fertilizer Materials:
a. Urea (46-0-0) b. Ordinary Superphosphate (0-20-0) c. Muriate of Potash (0-0-60) General Formula: Weight of Fertilizer Material (FM) =
Step 1. Weight of Urea =
90 46
Weight of Nutrient
X 100 or
% Nutrient 90 .46
= 195.65 kg Step 2. Weight of OSP =
60 20
X 100 or
60 .20
= 300 kg Step 3. Weight of MP
=
30 60
X 100 or
= 50 kg
30 .60
X 100
5.1.1.2.
Recommended Rate: 90-60-30 kg NPK/ha
Available Fertilizer Materials: a. Ammonium phosphate (16-20-0) b. Ammonium sulfate (21-0-0) c. Muriate of potash (0-0-60)
S tep 1. Weight of Ammophos =
60 20
X 100
= 300 kg Note: Since ammophos contains two elements, phosphorous (P) and nitrogen (N) therefore, we already satisfied the 60 kg requirement for P2O5 and another 60 kg for nitrogen. Again, nit the recommended rate for N is 90 kg/ha therefore we haven’t satisfied its amount. So, we have to subtract 60 k from the recommended 90 kg N, hence, the remaining 30 kg N will be taken from ammonium sulfate. 30
S tep 2. Weight of Ammonium Sulfate = S tep 3. Weight of Muriate of Potash =
21
30 60
X 100
X 100
= 50 kg 5.1.1.3.
Recommended Rate : 100-60-60 NPK/ha
Available Fertilizer Materials:
a. Complete fertilizer (14-14-14) b. Urea (46-0-0 )
S tep 1. Weight of CF =
60 14
X100 = 428.57 kg
RR: 100 kg N - 60 kg P 2O5 - 60 kg K2O - _ 60 kg N – 60 kg P2O5 – 60 kg K 2O
40 kg N
S tep 2. Weight of Urea =
40 46
X 100 = 86.96 kg
Methods of fertilizer application Villegas and Malixi (1977) stated that to get maximum benefit, the fertilizer must be applied where the plant can readily absorb it. Proper placement of a fertilizer will provide an efficient and continuous supply of plant nutrient and will prevent salt injury to the seedlings. The following methods of fertilizer application are:
1. Broadcast. The fertilizer material is applied uniformly over the entire area before planting or while the crop is growing. Topdressing refers to broadcast application on growing crops.Uniform distribution of the fertilizer enables safe application of large quantities of fertilizer without injuring the crop. However, it may reduce fertilizer efficiency because of fertilizer fixation or by volatization.
2. Localized application. The fertilizer is applied close to the seed or plant, either in band adjacent to the plant rows (side dressing) or by plow-sole application. In the plow-sole method, the fertilizer is covered lightly with soil before seeding or planting. Localized application is especially essential for high rate applications of high analysis fertilizers. This methods is commonly used for most vegetables.
3. Foliar application. Plant nutrients may be applied on the aerial part of the plant. The dissolved nutrient must penetrate the cuticle of the leaf or the stomata and then enter the plant cells. This method is usually employed only in applying micronutrients. Marginal leaf-burn could occur with the application of high concentrations of fertilizer.
4. Applied with the seed – Fertilizer is broadcast together with the seeds or to seeds are coated with fertilizer by means of an adhesive such as cellofas or gum Arabic.
5. Fertigation – This involves dissolving the fertilizer materials in water and then apply it with the use of sprinkler.
Methods of determining soil fertility According to the Training Manual in Horticulture of MIT (2007) the methods of determining soil fertility are as follows:
1. Field fertilizer trials. As the term implies, field fertilizer trial experim ent is carried out in the fiel d. It could be conducted in different places under different seasons. When managed and conducted properly, the results obtained from this method are very reliable.
2. Soil analysis. It is a rapid method of assessing the fertilizer needs of crops. The principle involved is that the amount of available nutrients in the soil are directly related up to a critical point with the growth and yield of crop.
Soil analysis consists of four phases namely: 1. proper collection of soil samples 2. chemical analysis 3. interpretation of analytical results 4. formulation of fertilizer recommendation
3. Plant tissue analysis.
This is customarily made of fresh plant tissue in the field. It is a quick way test and is important in the diagnosis of the needs of growing plants. Sap from ruptured cells is tested for assimilated N-P-K. Test for other elements such as Mg and Mn are also done. The concentration of the nutrients in the cell sap is usually a good indication of how well the plant is supplied at the time of testing.
4. Nutrient deficiency symptom. An abnormal appearance of the growing plant may be caused by a deficiency of one or more nutrient elements. This visual method of evaluating soil fertility is unique and it requires no expensive equipment. It can also be used as a supplement to other diagnostic techniques.
Loss of nutrients from the soil The fertility of the soil is not lasting. It is usually lost through mismanagement by farmers who work in the land.
There are many ways in which soil fertility is depleted.
Loss through the crops. Plants utilize large quantities of nutrients from the soil for their growth. The plants having reached their maturity are harvested and sold. Thus, the organic and the minerals that composed the harvested crops are taken away from the farm. The constant removal of soil fertility through the crops will make the soil poor. This is the reason why production will decrease year by year if we do not fertilize our crops. The amount of soil nutrient lost through the crops depends on the kind of crops grown.
From the standpoint crops may be classified into three categories:
1. Heavy feeders are those crops that utilize a large quantity of all the three essential elements or it may be a heavy feeder as regards one element but a light feeder as regards to another. 2. Medium feeders consume not much of the food elements not like the heavy feeders. 3. Light feeders consume only little amount of the plant food elements. Loss of plant food through surface run-off. Rain water or excess irrigation water
which runs off the surface of the ground may carry not only soil particles and the food they contain but also the plant food which get dissolved in the running water.
Loss of plant food through leaching. Even if we do not plant, the minerals in the soil may be lost by leaching, that is, the soluble substances go with the water that drains down to the lower depths of the soil beyond the reach of the roots. This is especially true in cases of sandy soil.
Soil erosion. This is the greatest enemy of the farmer. Erosion is the removal of soil from the field through natural forces.
Soil nutrients are lost through harvesting, leaching, prolonged wet weather, melting snow, flooding and de-nitrification. Sustainable agriculture involves returning nutrients to the soil in the form of green manure, crop residues, composted manure and other wastes to improve and maintain soil life. During the growing season plants fix carbon dioxide by photosynthesis. Around 20 to 25 percent of this fixed carbon is returned to the soil through plant roots.
Healthy soil consists of fungi, microbes, earthworms, macrofauna and micro/mesofauna. Sustainable Agriculture involves not only the physical properties and mineral structure of the soil, but also the process by which organic matter is transformed into humus by microbes, fungi, earthworms etc. Incorporating crop residue and other organic matter into the soil promotes microbial growth which in turn promotes humus production and soil fertility. http://ecochem.com/trial_fvr_master.html A heavy rainstorm may splash as much as 90 tons of soil per acre. However, the majority of the soil splashed is not immediately lost from the field. Most of the splashed soil particles don't leave the field; they clog surface pores, which in turn reduces water infiltration, increases water runoff, and increases soil erosion.http://www.extension.iastate.edu/CropNews/2008/0604MAlKaisiMHelmers.htm
Methods of conserving soil fertility Soil is one of the most important natural resources. We need to devise and implement ways of conserving soil.
Ways of conserving soil fertility according to 1. Plant trees. Roots of trees firmly hold on to the soil. As trees grow tall, they also keep rooting deeper into the soil. As their roots spread deep into the layers of soil, they hold it tightly, thus preventing soil erosion. Soil under a vegetative cover is saved from erosion due to wind as this cover acts as a wind break. 2. Build terraces: terracing is a very good method of soil conservation. A terrace is a leveled section of a hilly cultivated area. Owing to its unique structure, it prevents rapid surface runoff of water. Terracing gives the landmass a stepped appearance, thus slowing the washing down of soil. Dry stonewalling is a method used to create terraces in which stone structures are made without using mortar for binding. 3. No-till farming (zero tillage). The process of preparing soil for plowing is known as tilling. The process of tilling is beneficial in mixing fertilizers in the soil, making rows and preparing the surface for planting. But the tilling activity could lead to compaction of soil, loss of organic matter and the death of soil organisms. No-till farming is a way to prevent the soil from this harm. 4. Contour plowing. It is a method of plowing across the contour lines of a slope. This method helps in slowing the water runoff and prevents soil from being washed away along the slope. 5. Crop rotation. Some pathogens tend to build up in soil if the same crops are cultivated again and again. Continuous cultivation of the same crop also leads to imbalance in the fertility demands of the soil. To save the soil from these adverse effects, crop rotation is practiced. It is a method of growing series of dissimilar crops in an area. It also helps improve soil structure and fertility. http://wwww.buzzle.com/articles/10-ways-to-conserve-soil.html http://people.oregonstate.edu/~muirp/sustfert.htm claims that crop rotation can also decrease the need for inorganic supplements. Rotation also can have beneficial effects on pest reduction, and mulches (as in cover crops during winter) can decrease weeds and increase retention of soil.
6. Apply fertilizers only at certain seasons. This would involve applying fertilizer only when the crop is there (or nearly there, as when it has just been planted or just before that) and able to take it up. http://people.oregonstate.edu/~muirp/sustfert.htm 7. Utilize crop residues more effectively 8. Utilize manure more effectively. 9. Water the soil. We water plants, we water the crops, but do we water the soil? We seldom do. Watering the soil is a good measure of soil conservation. Watering the soil along with plants growing in it is a way to prevent soil erosion caused by wind. 10.Mulch is a covering placed over soil to protect from erosion and improves water holding capacity of the soil. It serves as a good source of nutrients for plants and helps them sustain in times of drought and dry seasons. http://people.oregonstate.edu/~muirp/sustfert.htm Soil conservation is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination. It is a component of environmental soil science. There are conventional practices that farmers have invoked for centuries. These fall into two main categories: contour farming and terracing, There are many erosion control examples such as conservation tillage, crop rotation, and growing cover crops Windbreaks are created by planting sufficiently dense rows of trees at
the windward exposure
of
an
agricultural
field
subject
to wind erosion
http://en.wikipedia.org/wiki/Soil_conservation
Soil organisms
When worms excrete egesta in the form of casts, a balanced selection of minerals
and
plant
nutrients
is
made
into
a
form
accessible
for root uptake. US research shows that earthworm casts are five times richer in available nitrogen, seven times richer in available phosphates and eleven times richer in available potash than the surrounding upper150 mm of soil. The weight of casts produced may be greater than 4.5 kg per worm per year. By burrowing, the earthworm is of value in creating soil porosity, creating channels enhancing the processes of aeration and drainage. http://en.wikipedia.org/wiki/Soil_conservation
Importance of composting
Students of the Jones Rural School performing composting (Heap composting) during their TVE class
Sangalang, J.B. et.al Soil Management (1977) claim that the composting process involves decomposition of organic materials to form small bits of organic matter called compost. The whole process is done by organisms that use organic matter principally as a source of carbon and secondarily as a source of nitrogen and other elements for their growth and reproduction. If the organic matter contains little or no N, the microorganism get if from the soil. A majority of the decomposers are microorganism. Macroorganisms such as earthworms, termite, and other insects also contribute in breaking down organic materials. Therefore, the two requirements for the process to occur are (1) composting materials and (2) decomposers to speed up the process, the composting materials must be easy to decompose, and the needs of the microorganisms must be adequately supplied.
What do compost organisms need? According to the Resource Manual in IPPM in Vegetables (2005) the needs of the compost organisms are :
1. Balanced diet of compost materials
“Browns” Browns are compost materials that are brown and dry. Examples of which are sawdust, dried leaves, straw and small twigs and others. “Browns” are high in carbon, which for microbes are energy food. “Greens” Greens are compost materials that are green and moist like kitchen wastes, grass cuttings and the like. “Greens” are high in nitrogen, which microbes need to make proteins
If you add about 3 parts of browns to 1 part of g reens, then the compost org anis ms will have a balanced diet.
2. Right amount of air and water If there’s a right amount of oxygen and moisture, microbes can rapidly grow and multiply. Too much or too little of water, the microbes die. Compost materials should have a thin film of water around them, and lots of pore spaces filled with air.
3. Right temperature Organic materials will eventually decay even in a cold compost pile. But the decay process is sped up in a hot compost pile. When bacteria and fungi grow rapidly, they burn a lot of food, and give off a lot of heat. If the compost pile is big enough, the heat will build up inside the pile. Bacteria that grow well at high temperature take over and speed up the decay process.
Methods of composting Composting is the rotting down of plants and animals before the residue is applied to the soil. There are just as many composting techniques as there are methods of farming. That is, everyone and their grandmother has specific composting methods that work best for them; however, some techniques have stood the test of time. And those are the techniques that we have listed below.
Sheet Composting Sheet composting, also known as sheet mulching, can be a great way to add organic matter back into your soils. Essentially, this composting technique entails spreading thin layers of organic materials (i.e. compost ingredients) on top of the soil surface. Some also consider this technique to be "composting in place." Using green manure is another means of sheet composting. This technique is often used on a large scale, however, it can also be done successfully in your backyard.
In-vessel Composting In-vessel composting is becoming more and more popular with large-scale compost producers. This method involves composting within an enclosed containment system, often a large cylindrical-shaped container. The equipment involved in setting up an in-vessel composting system is typically quite expensive, and therefore usually limits it's usage to industrial-sized composting operations. Some smaller vessels do exist, however, they are often pricey. There are numerous benefits of in-vessel composting, such as an increased processing speed, year-round composting, and a highly controlled environment.
Anaerobic Composting Anaerobic composting describes the biological breakdown of organic materials by living anaerobic organisms. This may not be the most odor-rific composting method, but it can be quite effective. Some of the benefits of composting anaerobically include the following: it is one of the most basic means of producing compost; it can be done on a small scale; and it typically produces more humus per unit of starting material than most other composting methods.
Trench Composting Trench composting involves digging holes in your garden soil and burying raw compost ingredients. Some people swear by this method, whereas others want nothing to do with it. Similar to anaerobic composting, this method of decomposition is quite simple, however, the materials tend to take longer to breakdown than when using other composting techniques.
Bokashi Composting Bokashi is a Japanese term meaning fermented organic matter. Therefore, bokashi composting d escribes the making of compost via fermentation. To achieve optimal results, your compost materials are inoculated with a microbial starter culture, and placed inside a sealed container. These starter cultures consist of several different species of microorganisms, all of which thrive in anaerobic conditions. One of the most popular microbial inoculants is called Effective Microorganisms or EM.
Composting Barrels Composting barrels, or compost tumblers, are a great composting technique for backyard growers. They are self-contained, clean, and if big enough, can produce a fair amount of compost in a short period of time. You can buy composting barrels from a commercial supplier or you save your money and make one yourself. We discuss both approaches on the following page. http://www.compostjunkie.com/composting-techniques.html
Vermicomposting Composting is the process of converting organic materials like leaves and animal manure into “humus” an organic matter through decomposition by the action of microbes and other organisms. Humus is rich in nutrients and contributes to soil texture and water retention.
Normal decomposition of grass cuttings can take up to six months. However, this can be accelerated to as short as 30 – 45 days by the use of earthworms to digest the organic materials. This is called vermicomposting (vermis in latin) that yield beneficial by-products known as vermicompost or vermicast. In a single process, we are given two products – vermicast which is pure worm excreta and worm biomass. The production of vermicompost is timely since inorganic fertilizer is now becoming very expensive and that there is also an increasing demand for organically produced agricultural crops and an added benefit is that the earthworm can be made into high protein animal and fish feed supplement.
STEPS IN VERMICOMPOSTING 1. Gathering of materials Examples - rice straw, grass, leaves, kitchen wastes, animal manure, used mushroom substrate. These materials should be shredded as the earthworm may not be able to digest them effectively. Add some animal manures to increase the n itrogen content of the m aterials.
Picture of materials for vermi 2. Selecting the site The site should be airy, dry, near water source, and raw materials for the food of the earthworms. The area temperature should be around 260C.
SELECTING THE WORM HOUSING
Wormbins/wormbeds may be made out of different materials like iron bars, old plastic basins, split bamboo or hollow blocks.
Wormbins out of plastic beddings
Windrows Windrows are piles of substrates that are decomposed before feeding them to the worms. They are usually about 1 meter wide and at least a meter high and can be of any length as desired. Preparation of beddings. Bedding is the living medium for the worms but also a food source. A wide variety of bedding materials can be used including newspapers, sawdust, rice straw, pre composted manure and dried leaves.
Anaerobic Stage (10-14 days) Arrange the materials or substrate into a bed about two (2) feet high under partial shade like a tree. Cover the bed with plastic for two weeks for anaerobic decomposition by bacteria and fungi present in the material until the temperature will rise to about 70°C.
Aerobic Stage (30-35 days) When the temperature of the bed cools, remove the plastic cover. The media should smell sweet. Maintenance of the worm beds.The moisture content must be 60-80% (when a fistful is squeezed a few drops of water should drop). Place the earthworms on top, at the rate of 1kg per square meter. Put sidings of hollow blocks or sawali. Protect against birds, cats, rats etc., as well as heavy rains as nutrients will leach.
Harvesting, Drying, and Storing
After 45-60 days pass the materials through a sieve to separate the worms from the decomposted leaves. The worms can be recycle into other composting beds or made into vermi-meal. The compost should be spread-out to dry for one day ready for sale, The vermicast is then prepared for packaging. The final products are placed in bags ready for storage, distribution or use.
student
of
the
Floridablanca
National
Agricultural
A School,Floridablanca,
Pampanga shifting gathered vermicompost.
Vermicompost ready for sale (Courtesy Floridablanca National Agricultural School,Floridablanca, Pampanga ) TIPS: Compost is ready to use when it is dark brown, crumbly and has an earthy smell. Manual extraction. Pick worms by hand and transfer them to a new wormbed. The vermicompost may be allowed to dry in the shade for a few days and then sifted if a finer compost is desired. Pyramids of egypt. In the shade, pile the vermicompost in such a manner that it looks like a pyramid. After a day, you can harvest the top part easily because the worms have gone to the bottom of the pile. When you reach the bottom of the pile, you can extract the worms manually. Migration. Move the contents of the whole bed to one side. Fill the empty half with new substrate. •
•
Allow the worms
to move freely to the new food.
PARTIAL EXTRACTION WITH NET BAG.
Fill an onion bag with fresh food and bury it in the middle of the bed. After a week or so, the bag will be filled with worms which you can empty to a new worm bed. This facilitates the gathering of worms.
Onion bag filled with fresh food for the worms (Courtesy Floridablanca National Agricultural School,Floridablanca, Pampanga.)
Table 9. Table of compost materials http://eartheasy.com/grow_compost.httm Material
Carbon/Nitrogen
Info
table scraps
Nitrogen
add with dry carbon items
fruit & vegetable scraps
Nitrogen
add with dry carbon items
eggshells
neutral
best when crushed
leaves
Carbon
leaves break down faster when shredded
grass clippings
Nitrogen
add in thin layers so they don't mat into clumps
garden plants
--
lawn & garden weeds
Nitrogen
only use weeds which have not gone to seed
shrub prunings
Carbon
woody prunings are slow to break down
straw or hay
Carbon
straw is best; hay (with seeds) is less ideal
green comfrey leaves
Nitrogen
excellent compost 'activator'
pine needles
Carbon
acidic; use in moderate amounts
flowers, cuttings
Nitrogen
chop up any long woody stems
seaweed and kelp
Nitrogen
apply in thin layers; good source for trace minerals
wood ash
Carbon
only use ash from clean materials; sprinkle lightly
chicken manure
Nitrogen
excellent compost 'activator'
coffee grounds
Nitrogen
filters may also be included
use disease-free plants only
tea leaves
Nitrogen
loose or in bags
newspaper
Carbon
avoid using glossy paper and colored inks
shredded paper
Carbon
avoid using glossy paper and colored inks
cardboard
Carbon
shred material to avoid matting
corn cobs, stalks
Carbon
slow to decompose; best if chopped up
dryer lint
Carbon
best if from natural fibers
sawdust pellets
Carbon
high carbon levels; add in layers to avoid clumping
wood chips / pellets
Carbon
high carbon levels; use sparingly
Perform irrigation and drainage practices Agricultural irrigation is the application of water to crops through artificial
means. Irrigation is
primarily
used
in
areas
with
sporadic
rainfall
or
potential drought conditions to ensure crop soil receives adequate water for cultivation. The water utilized in agricultural irrigation can come from various sources, such as groundwater, rivers, springs, lakes, wells, or surface water Benefits of irrigation
1. Irrigation is an insurance to drought. 2. It enables the growing of quick maturing crops. 3. It is a guarantee to the quick germination of seeds. 4. It is a means of securing early maturity on most crops. 5. It increases quality, attractive appearance and yield of crops.
Technical methods used to measure soil moisture content at periodic intervals during the growing season according to Caoili and De Vera (p112) Vegetable Production: Water Management for Vegetable Production. 1. Direct method by gravimetry with oven drying . The method involves the weighing the wet sample, removing the water by oven drying and reweighing the sample to determine the amount of water removed. The percentage of water in the sample on a dry-weight basis is obtained by dividing the difference between wet and dry masses by the mass of the dry sample, and multiplied by 100.
2. Use of tensiometer. Tensiometer measures soil water content. Water content in the soil is then obtained from the calibration curve relating soil suction to water content values for specific soils.
3. Electrical resistance method . 4. Temporary wilting. When water stress occurs in plant, cells lose turgidity and plants show symptoms of wilting. Temporary wilting may occur at mid-day when water demand reaches its climax, especially during the hottest months of the year. Soil moisture may really be adequate but transpiration may outpace water absorption. If this is, plant will recover by evening. However, if plants wilt in the morning continuously for 3-4 days, water may indeed be lacking and the crop must be irrigated immediately
5. Color of foliage. Not all plant show temporary wilting when water is limited. Instead, their leaves turned yellowish as in beans and in some cases bluish green as in eggplants, as the water is reduced in the soil. Color is an indicator of plant variety where there is nitrogen supply so take this into account.
6. Rate of growth of the plants. If the rate of growth of the crop is sluggish, water may
not be enough. 7. Sand-cum-soil-mini plot technique . It involves digging thoroughly a one cubic meter pit in one part of the field. Mix 5% sand to the soil which has been dug and return it to the pit. Now the soil as reduced water holding capacity. The crop including the test plot is planted as usual. The plants in the test plot will start to wilt 2-3 days ahead of those in the field. Irrigation must be done when wilting is observed in the test plot. 8. “Feel of the soil”.
Get samples from a depth where most of the roots occur and try
to feel the soil. This depends on the type of the soil.
Table 10. Table of irrigation schedule
Type
of Irr ig ation is needed
s oil Sandy
Appears to be dry, but does not form a ball when squeezed
Loam
Somewhat crumbly but holds together
Clayey
Somewhat pliable, forms a ball, too dry to form ribbon easily (ribbon is formed between thumb and forefinger)
Methods of irrigation
1. Manual irrigation is one of the most basic types of agricultural irrigation. Farmers or laborers use watering cans to saturate the crops by hand. Since manual irrigation is often time consuming and physically demanding, it tends to be used for small farms or in poverty-stricken areas. 2.
Before advances were made in irrigation technology , surface irrigation tended to be the most implemented irrigation system for large scale watering. In surface irrigation, small canals are dug across the entire length of the crop area and water is poured at the top of the canals. Surface irrigation uses no pumps or other mechanisms and relies on gravity to distribute water across crops through the canals.
3. Sub-irrigation is a method often used for field crops such as peppers or tomatoes. The method applies water to crops from below the soil’s surface. A pipe system is buried beneath the roots of the crops and the water is pumped upwards into the roots to ensure the roots receive the correct water amounts.
4. C enter pivot irri g ation uses an automated system of sprinklers that are attached to fixed towers in the center of the crop area. The sprinklers rotate in a circular motion to evenly distribute water across the entire crop area. Center pivot is often used in flat, spacious crop areas.
5. Windmill irrigation . 6.
Drip irrigation
7. Irrigation by power machinery . Water pumps are set in the source of water. Water is delivered to the field through water hose.
8. Irrigation by hand . This requires hand labor. This system is used only where a valuable crop can be grown in a small piece of land, as in school and home gardens. Water is applied either early morning or late in the afternoon.
Rainfall is referred to as the natural irrigation.
Causes of loss of irrigation water 1.
Over irrigation. A farmer should not use more water than his crop needs. The
amount of water needed by crops varies with the crop, and a farmer should ascertain what amount is for each crop and how it is best distributed among the different times of application. 2.
Poor grading of land . When a piece of land to be irrigated is not uniformly or
properly graded, as for example, when certain spots are high while others are low, or when there is hardly any grade at all to allow movement of water by gravity, there will be loss of water. 3.
Seepage is the horizontal passage of water from irrigation canal through the
surrounding ground. Loss of water by seepage is prevented by lining the canal properly with a clay puddle. 4.
Deep percolation . Percolation is the vertical downward movement of water.
Water which sinks much deeper than the roots of the plants is wasted water. Skillful cultivation should prevent much loss of water due to deep percolation. 5.
Run-off at the ends of fields or furrows. To avoid waste of water in the form
of run offs, it is necessary to supervise carefully the irrigation work so that only enough water is allowed to flow in the irrigation furrows. 6.
Direct evaporation. This refers to the loss of water from plant parts, soil
surface and even from bodies of water with the aid of sunlight.
Drainage Drainage is defined as the process of removing water from the soil in order to increase its productivity. Drainage is important on lands for growing vegetables and the upland crops. This requirement has particular reference to fertilizer application, mechanical weeding and cultivation, aeration, soil temperature and structure, readiness for the next rotation crop, early and deep root development, and many others. The lack of drainage systems where it is required leads to gradual rise of the water table, waterlogging, salinity or alkalinity problems. Lands with long years of poor drainage provisions may be rendered unproductive, ( Caoili and De Vera (p112) Vegetable Production: Water Management for Vegetable Production.) said.
According to the Lecture Notes in Agronomy 11 of NVSIT there are benefits derived from drainage as follows: 1. 2. 3. 4. 5. 6.
It It It It It It
improves the tilth of the soil. leads to the improvement of soil aeration. improves the temperature condition of the soil. increases availability of plant food. encourages multiplication and development of useful organisms in the soil. increases benefits obtained from the use of fertilizers.
Systems of drainage 1.
Surface drainage, also called open drainage
2.
Under-surface drainage
3.
Combination of surface and under surface drainage
4.
Vertical drainage – the water runs more or less vertically through the soil into a porous bed of sand or gravel beneath.
What to Process In your previous activities you discussed among your group mates how to maintain lives of living things. Among their needs food is the most important. Go to your garden and observe/diagnose your plants. Are they doing well? Do they need something? Remember they are in their vegetable growth.
Weeding
Courtesy of Jones Rural School
Weeds are many home gardeners’ biggest enemy. Roundup and other chemicals may seem like the best weapon in the arsenal against weeds. However, many experts discourage the use of chemicals. They can leach into fruits and vegetables. They also runoff and trickle down into groundwater. Weeds considerably yield losses in vegetable crops because they compete for light, water, carbon dioxide and soil nutrients with the cultivated crops alternate hosts for crop pests and pathogens. Weeds, in general, precede crops on farming lands and are major yield reducing factors. In ecological terms, most annual weeds are r-strategists, establishing populations with high relative growth rate (r). Thus, they produce numerous viable seeds and their populations quickly build up, in an exponential pattern. Weed competition with crops reduces agricultural output (quantity and quality), and increases external costs by spreading them across farm boundaries. It is als o a major constraint to increased farmers’ productivity, particularly in developing countries where weed control claims 20 to 50 % of farmers’ time and keep smallholders in a vicious circle of poverty. home/managing-ecosy http://www.fao.org/agriculture/crops/thematic-sitemap/theme/spi/scpi-stems/integrated-weedmanagement/en/ Paller and Soriano claim that (1977) (Weed Control in Vegetable Fields) Vegetable Production explain that poor timing of physical weed control required for effective control and for maintenance of good soil structure. Cultivating when weeds are still small, and also when the vegetables are still small, will result in efficient weed control before weeds offer serious competition to the crops.
Methods of weed control 1. Start with prevention. Prevention also known as exclusion, begins with securing clean seed and feed sources. Every opportunity should be taken to prevent new weeds from being introduced to the farm. Care should be taken to select seed and feed sources that are free of weed species that are not currently present on the farm, particularly invasive or noxious.
Build healthy soil with compost and mulch – soil organisms protect plants from many disease and insect pest problems. Select pest-resistant plants, and put them in the sun/shade and soil conditions they like. Clean up disease infected plants, and compost dead plants to reduce hiding places for insect pests.
Pull weeds before they go to seed and spread.
Use a variety of plants, so if pests attack one plant, others can fill its place.
2. Biological control. Accept a little damage. Give nature time to work Natural predators often bring pests under control, but they need time to work. Most bugs are good bugs: only about 5% of the bugs in your yard are pests. “Good bugs” like ground beet les, lady bugs, and lacewings help control pests. Don’t spray at the first sign of damage – nature may control it for you, or plants often just outgrow the damage. Other biological control measures are by pasturing and using clean seeds for planting.
1. Use chemical pesticides as the last resort If you must use a chemical pesticide, use the least toxic product, and spot apply it. Don’t spread it all over the yard to kill a few weeds or bugs. It may be best to have a professional who has all the protective gear do the application, but don’t use services that spread chemicals over the whole yard or spray on a calendar schedule. You want to apply pesticides only when and where you really have a problem. Follow label instructions exactly – more is not better. And be sure to keep children and pets out of application areas. If a pest or weed problem develops, use the least toxic solution
Physical controls like traps, barriers, fabric row covers, or repellants may work for pests.
Long handled weed pullers pop dandelions out easily.
Mulching once a year reduces weeds in beds.
Less toxic products like soaps, horticultural oils, and plant-based insecticides that work for many problems are now available – see Grow Smart Grow Safe below.
Beneficial insects that prey on problem bugs are available for sale, or you can attract these “good bugs” by planting a variety of plants that provide pollen and nectar all year.
Think twice before using pesticides Pesticides (weed and bug killers) can damage soil and plant health, poison wildlife like birds and salmon, and harm our families health. The good news is that we really don’t need those chemicals to grow a healthy, attractive landscape. Try these natural methods.
Tips for selecting and using herbicides:
Be sure to read, understand and follow all of the label directions when mixing and applying herbicides.
Make sure the label clearly states that the product can be used in the manner you intend to use it.
Remember, more is not better. Use the application rate on the label.
Some herbicides are selective, and only kill certain types of plants, while others are non-selective and kill almost any type of plant.
Some herbicides kill weeds quickly, others can take up to a week or more.
Some herbicides persist in plants and soils for long periods of time, while others only remain in plants or soil for a short time.
Some herbicides have active ingredients that are more likely to move through soils towards groundwater. Others are much less likely to move through soils. http://npic.orst.edu/pest/weeds.html
1. C ultural methods a. Replace problem plants with pest- resistant ones If a plant, even a tree, has insect pest or disease problems every year, it’s time to replace it with a more pest-resistant, site-adapted variety or another type of plant that doesn’t have these problems. b. Crop rotation c. Field sanitation. Sanitation from the perspective of weed management, refers to the practice of minimizing the movement of weeds that are found on the farm to other parts of the farm. The primary activities of sanitation involve keeping equipment free of seed or other reproductive parts of weeds, and ensuring that field boundaries and other non-crop areas are kept free of weeds capable of reproducing. There is significant overlap between the activities carried out in both prevention and sanitation. http://www.seattle.gov/util/EnvironmentConservation/MyLawnGarden/PestWeedDiseaseControl/index.htm
2. Mechanical/Physical control like hand pulling, hoeing, cultivation and mulching, smothering. This is done by depriving the weeds of complete sunlight, cutting, and burning
Why should we control weeds?
According to the Lecture Notes in Agronomy 11 of NVSIT we control weeds because:
Weeds cause decrease in crop production because they compete for nutrients, moisture, light and space. Weeds increase labor and of production cost. Some weeds harbor plant pests which may affect plant growth and yield. Weeds clog irrigation and drainage canals or ditches hampering flow of water resulting to overflow and waste of water resources. Some weeds are injurious to man and animals. Weeds lower land value. Root of weeds interlace with roots of plants which makes cultivation and weeding difficult. Weeds cause the wear and tear of farm implements or equipment.
Principles of weed control To control weeds successfully, understand thoroughly their nature, life history, habit of growth and their methods of natural reproduction. It is necessary to know if a weed is terrestrial or aquatic. It is necessary to know whether weeds are resistant to drought or to water lodging or easily affected by these conditions. It is important to know if its method of reproduction is by seeds, by underground vegetative parts, or both.
Types of weeds Types of weeds is enumerated and explained in the Lecture Notes in Agronomy 11 of NVSIT as follows :
I. Grasses. Grasses are monocotyledonous plants which have long, narrow, tworanked, usually flat leaves with parallel veins and round, hallow stems. The common examples of grassy weeds are: 1. Echinochloa crusgali (L. Beauv.) Local names: Philippines Dayakibok Tagalog Dauadaua Bicol Lagtom Japan Inubie 2. Echinocloa colunum Local names: Philippines Bulang tiribuhan Tagalog Bulang tiribuhan Ilocano Dalakayang, Dakayan Thailand Thai-Yak Nok Sri Champu
II. Sedges. Sedges are similar to grasses but have three-ranked leaves and triangular solid stems. They frequently have modified rhizomes for storage and propagation. Examples: 1. Fimbristylis littoralis Gaud. Local names: Tagalog
Ubod-ubod
Pangasinan
Gumi
Ilocano
Siraw-siraw
2. Cyperus iria Linn. Local names: Philippines Japan
Alinang, sud-sud Kogome-gayatsuri
III. Broadleaved weeds are dicotyledonous plants with net-veined leaves. Examples:
1. Monocharia vag inalis Presl. Local names: Philippines Gabing uwak Tagalog Biga-bigaan Ilocano Bil-lagut Bicol Upiup
2. S phenoc lea zeylanica Gaertu. Local names: Philippines Dilang butiki Tagalog Silisilihan Visaya Mais-mais
Grass
Sedge
Broadleaved weed
Cultivation Cultivation is a tillage operation of loosening or breaking up the soil about
growing crops or plants in order to maintain it in condition favorable for their growth. Benefits of cultivation: 1.
Control the growth of weeds. Weeds are referred to as the chief plant competitor. There is a saying that runs thus, “ The best way to control weeds is to remove the bitter roots”, and this is only accomplished through cultivation.
2.
Cultivation aerates the soil to facilitate the respiration of plant roots and micro-organisms as well as to supply nitrogen for nitrogen-fixing organisms. During rainy season, the soil lacks air because spaces in between soil particles are filled with water. If you drain the soil the soil air can circulate in between soil particles. Cultivation also creates more spaces between soil particles to accommodate air.
3.
Help conserve food materials in the soil. It is generally known, however, that when cultivation kills weeds, moisture is conserved because dead weeds have no more chance to use the soil moisture as well as food nutrients in the soil
4.
It makes the top soil loose to increase its capacity to absorb water. There are two ways of cultivating the crops according to the Training Manual in Horticulture prepared by the Maddela Institute of Technology (2007) as follows:
Hilling-up. Hilling up usually refers to loosening/breaking the about growing
plants either in rows or per hill. This is done by bring the soil towards the base of the plant. The primary purpose is to cover the applied fertilizer, cover the base of the plant , and to to control the growth of weeds.
Off-barring. The soil is cultivated away from the plants.
Frequency of cultivation The ideal way of taking care of an annual crop like vegetables is to keep the field free from weeds and the soil in excellent tilth all the time through cultivation. This is usually done in gardening and so when a field receives about the same amount of attention, we often say we “garden” the field. By this we simply mean we give the field a very intensive care just as we generally do to a garden. Usually, however, we cultivate as many times as we can to keep the weeds down and prevent them from existing in abundance.
Depth of cultivation As a rule, cultivation should be at a depth of about 5 centim eters. It should be deep to kill weeds. It is not advisable to cultivate deeper than it is necessary to kill the weeds because the roots of the cultivated plants may be injured. The depth varies according to crops.
Time of cultivation Cultivation is done after planting and before the crops cover the ground. Since cultivation is actually a process of working the soil, the rules governing plowing with reference to the condition of the soil should apply to cultivation.
Below is the time table when to hill up the following vegetable crops.(MIT Training Manual p.71) Table 10. Schedule of cultivation CROP
WHEN TO CULTIVATE
Beans and peas
2-3 weeks after planting
Eggplant
2-3 weeks after planting
Pepper
2-3 weeks after planting
Potato
8-10 cm tall or approximately 30 days after planting
Lettuce
2-3 weeks after transplanting
Chinese cabbage
2-3 weeks after transplanting
Celery
2-3 weeks after transplanting
Carrots
30 days after transplanting
Cabbage
2-3 weeks after transplanting
Cauliflower and broccoli
25-30 days after transplanting
Tomato
2-3 weeks after transplanting
Tools/implements/equipment in cultivation The tools, implement, and equipment used in cultivation depend on the area o be cultivated. For vegetable gardens in school and in the backyard, the simplest cultivating tools such as the hand trowels and hand fork which are used. In their absence, bolo as a general tool can be used. In the case of wider area, hoes, next in simplicity among implements for cultivation are specially adapted for use on land where animal drawn cultivators can not be used, and for cultivating spaces between plants in the row that can not be reached by other cultivators.
Cultivators. A cultivator is an implement used for cultivation and consists usually of a frame to which shares are attached. Cultivators may be either propelled by hand or drawn animals, tractor or cable and are used in cultivating wide vast of land.
Hand cultivators. Cultivators which are used with hand power are usually called hand cultivators.
Animal drawn cultivators. The use of animal drawn cultivators is preferred than hand machinery because they are more economical to operate.
Tractor cultivators. These type of cultivators are not used in the culture of annuals or crops which require fairly close distancing since the tractors need a good deal of free space for passage.
What to transfer Activity 4.
In your own vegetable gardens which I let you prepare before and which you already have planted with your vegetable crops, perform weeding and cultivation following the knowledge and skills you have learned in your lesson. Include weeding and cultivation operations in your diary of activities which I required you to prepare. Write a short report of about 100 words on how you practiced weeding and cultivation. Include in your report how you felt about your work.
Control of insect pests and diseases
Insects and their characteristics Pests in any form are the farmers’ enemy and they cause enormous damage to their crops. Most often, pests spell the difference between high and little or no harvest at all. The quantity and quality are impaired through the production of small produce, change in the taste and smell, discolored, and even the presence of insects in them. The production of quality and quantity produce does not only depend on the skill of the farmer but also the knowledge on how to control pests. http://www.reachoutmichigan.org/funexperiments/agesubject lessons/insect.html enumerates the concepts and facts about insects as follows:
Concepts:
An insect is a very small animal with particular characteristics.
Insects are invertebrates. They have no backbones.
Most insects walk, but some can fly and jump.
Insects need water, air, and food to live.
Facts:
Most insects have five basic physical characteristics: 1.
Insects have what we call an exoskeleton or a hard, shell-like covering on the outside of its body.
2.
Insects have three main body parts: head, thorax, and abdomen.
3.
Insects have a pair of antennae on top of their heads.
4.
Insects have three pairs of legs. They use the legs for walking, but sometimes an insect may have a pair of legs that are specially designed for jumping.
5.
Insects have two pairs of wings.
Some insects are helpful to people and some are not. Parts of an insect as shown in the CBLM of Tech-Voc
The grasshopper and its parts
The grasshopper and its parts 1. The head is the anterior of the three body regions of an adult insect. It bears the eyes (usually a pair of compound eyes), the antennae and the mouthparts. 2. The thorax is the middle of the three body regions of an adult insect. It is composed of 3 segments. It bears 3 pairs of legs (one on each segment) and usually 2 pairs of wings. Some insects have only 1 pair of wings.
3.The abdomen is the posterior of the three body regions of an adult insect. It is composed of 11 segments. The abdomen bears the external genitalia of the insect. In female insects these consist of an ovipositor.
4.The wings . Most adult insects have 2 pairs of wings, but some (for example flies) have only 1 pair of wings. Usually the wings are membranous but in some insects they can be leathery or hard. Sometimes the wings bear hairs or small scales.
5. The legs . Adult insects have 6 legs. Each of the segments of the thorax bears 1 pair of legs. The legs are segmented. Often the last segment of the leg bears a small claw. In some insects, the legs are specially adapted for jumping.
6. The antennae . The head of most adult insects bears a pair of antennae. Insects use the antennae to detect odors or they use them as tactile (touch) organs. Antennae are very variable in form and size.
7. The mouth. The mouthparts of adult insects can be of different types. In many species they are of the chewing type, for example in grasshoppers and beetles. Others have sucking mouthparts for example shaped like stylets in bugs and aphids or shaped like a coiled tongue in butterflies and moths. The different types of mouthparts determine how the insect feeds. http://bijlmakers.com/entomology/bodypart.
How does an insect grow ? Knowledge on the life cycle of the insects is important in the development of control measures that don’t rely on applying pesticides. Injury caused by insects is greatest at certain stages of their development . Bautista, et. al (1977) stated that most insects go through a complete metamorphosis (change) consisting of four stages: egg, larva (worm), pupa and finally the adult. It s during the larval stage that these insects do the most damage, as this is when most feeding and growth take place. Larvae of moths and butterflies are more commonly known as caterpillars, those of beetles as grubs, flies as maggots, certain groups of moths as cut worms, and click beetles as wireworms. On the other hand, some insects undergo gradual metamorphosis. The eggs hatch into nymphs, which resembles the adult insets but lack wings. The nymphs then undergo several stages before becoming adults. They feed on the same food plants as the parents. Most insects of this type are the sucking ones. Based on the Resource Manual in IPPM in Vegetables (pp112-113) an insect begins its life as an egg and changes its appearance as it grows. This is the process of metamorphosis. A small number of insects give live birth to their young, but for most insects, life starts inside the egg. Insects’ eggs are protected by hard shells, and although they are tiny and inconspicuous, they are often laid in vas t numbers. A female house fly for example may lay more than 1,000 eggs in a two-week period.
The Egg
The larval stage of an insect is the most destructive stage. Most damage is done to crops at this stage. The larvae grow from almost microscopic size when hatched. Larvae are ravenous eaters. When full size has been attained, the larvae either spin a cocoon or build a shell around themselves and go to a resting stage.
The Pupa The pupa is the rest period of the insect. The pupa develops into adult. “One day, a small opening appeared in a cocoon; a man sat and watched for the butterfly for several hours as it struggled to force its body through that little hole.”
The adult A mature adult emerges f rom the pupa. At this stage, the adult insect will lay eggs again to continue the cycle.
The Life Cycle of an Insect (Complete Metamorphosis)
In other insects, such as grasshoppers and aphids, the young insect (nymph) looks like the parent when it is hatched. It sheds its exoskeleton several times as it grows.
Ways on how insects damage plants
Based on the Lecture Note in Agronomy 11 of NVSIT, insects are classified as to how they damage the crops and how these insects are controlled. 1.) by chewing Insects feed by chewing some portions of theplant like leaves, stems, flower, and fruits. They have horn-like jaws which they use for biting and chewing. Grasshoppers, caterpillars, grubs, and beetles are examples of these insects.
2.) by sucking Insects also nourish themselves by sucking, plant juices and nectar. These have sharp, slender, hollow beaks which they insert under the surface of plants to suck their juices. San Jose scales, aphids,plant lies, squash bugs, and other tree bugs are sucking insects.
3.) by lapping Mouth parts of these insects enable them to lap or lick liquids from the outer surfaces of objects on which they feed. Apple maggots and cherry fruit flies are examples of lapping insects.
Methods of controlling insects A. Applied Control. This is a measure to destroy insects. Agriculturists have found
the following methods effective. I.
Chemical Control – This refers to the destructionof insect pests through the use of chemicals, such as pesticides and insecticides. This method is not environmentally friendly in the sense that it may kill other beneficial insects and offer harm to other living things like animals and men.
a.
Insecticides. These are substances that kill insects by their chemical action. 1.
Stomach poisons are spray, dust, or dips that kill the insect when they are swallowed.
2.
Contact poisons are spray, dust or dips that kill the insect with out being swallowed.
3.
Fumigants are chemicals in the form of gas to kill insects usually applied in an enclosure of some kind.
b. Auxiliary, synergistic or supplemental substances are materials added to spray or dusts which are not primarily toxicant but which make the insecticide cover more economically; stick or adhere better to plants; spread over foliage, fruits, or the bark, or the bodies of the insects more quickly or completely; bring insecticidal substances into solution or emulsions; mask distasteful or repellent properties of insecticides or activate the chemical action of the toxicant.
Examples:
Carriers such as water in a spray, talc in a dust, or bran in poison bait.
Emulsifiers such as flours, calcium and blood albumen.
Stickers such as lime, resin and glues.
Spreaders like wetting agents and detergents
Stabilizers such as caustic soda, glue, gelatin
c. Attractants or attrahents. These are substances used in poison baits,
spray or dust to induce
the insects to eat the poisoned materials or to lure insects into traps. d. Repellants are substances that keep insects away from crops and animals because of their offensive appearance, odor or taste.
II. Mechanical and Physical Control . These are special operations that kill insects by physical and mechanical action. Mechanical measures refer to the operation of machinery or application of manual operations. This is done through the following ways. a. manipulation of water or humidity ( draining, dehydrating or flooding the breeding media) b. manipulation of temperature like burning c. use of electric shock d. use of light and other radiant energy e. use of sound waves.
III. Cultural Control or Use of Farm Practices . Regular farm operations performed so as to destroy insects or prevent their injuries.
IV.
a.
Crop rotation
b.
Tilling of the soil
c.
Variations in the time or method of planting or harvesting
d.
Destruction of crop residues, weeds, volunteer plants, and trash
e.
Use of resistant varieties
f.
Pruning, thinning
g.
Fertilizing and stimulating vigorous growth
Biological Control . This is the introduction, encouragement and artificial increase of
predaceous and parasitic insects. a.
Protection and encouragement of insectivorous birds and other animals.
b.
The use of growing plants to destroy, repel or prevent damage by insects.
V. Legal Control. This is the eradication of insects by controlling human activities.
Inspection and quarantine laws prevent the introduction of new pests from foreign countries or their spread within a country.
Isolation and quarantine are government policies to protect the public, plants, and animals by preventing exposure to infected or potentially infected persons, plants, and animals. In general, isolation refers to the separation of persons, plants, animals, and the like who have a specific infectious illness from those who are healthy and the restriction of their movement to stop the spread of that illness. Quarantine, in contrast, generally refers to the separation and restriction of movement of persons, plants, animals, etc who, while not yet ill, have been exposed to an infectious agent and therefore may become infectious. Quarantine of exposed persons is a public health strategy, like isolation, that is intended to stop the spread of infectious disease. Both isolation and quarantine may be conducted on a voluntary basis or compelled on a mandatory basis through legal authority. Introduction of laws enforce the application of control measures such as spraying, the cleaning up of crop residues, fumigation and eradication measures. Insecticide laws govern the manufacture and sale and to prevent the adulteration and misbranding of insecticides. Poison residue laws fix the tolerance of various insecticides upon food products offered for sale or transportation.
VI. Natural Control. All the measures that destroy or check insects do not depend upon man for their continuance or success and can not be greatly influenced by man. 1. Climatic factor such as rainfall, sunshine, cold, heat and wind. 2. Topography factors such as rivers, lakes, mountains, type of
soil, other characteristics of the
country that serve as barriers. 3. Predators and parasites including insects, birds, reptiles, mammals.
Insect Pests of Vegetable Crops 1. Aphids Family: Aphididae Plants attacked: Most vegetables Type of damage: Aphids suck plants juices, may inject toxins into the plant, secrete a sticky substance called “honeydew,” or transmit certain plant viruses. Remember: Aphids are usually found in colonies on the underside of leaves. They may be winged but are usually wingless. Aphids are capable of rapidly increasing in numbers. Lady beetles and lacewings are effective predators of aphids. 2. White Grubs
Family: Scarabaeidae Plants attacked: Most vegetables Type of damage: Grubs feed on the roots or other underground parts of most vegetables. Damage typically consists of surface scars and round gouges. Characteristics: Grubs are mostly a problem in fields following sod. Weedy gardens are also attractive to ovipositing beetles. 3. Cutworms Family: Noctuidae Plants attacked: Nearly all vegetables Types of damage: The most common damage appears in young plants cut off at the soil surface. Cutworms may also climb the plant and feed on foliage and fruit. Remember: Damage can be reduced by keeping gardens free of weeds before and after vegetables are planted
4. Striped Blister Beetle
E picauta vittata Family: Meloidae Plants attacked: Many vegetables Type of damage: Adults feed ravenously on foliage Remember: This general feeder readily moves from plant to plant. The beetles can be picked off the foliage. However, they contain oil that can blister the skin if they are accidentally crushed. The larvae of blister beetles are beneficial because they feed on grasshopper eggs in the soil. 5. Wireworms Family: Elateridae Plants attacked: Many vegetables Types of damage: Wireworms feed on seeds and seedlings of corn, bean, and pea. They also cause wilting and often death of the plant. Wireworms feed on the marketable portions of potato, sweet potato, radish, carrot, rutabaga, and turnip. Wireworms also attack the roots of cabbage, cucumber, tomato, onion, watermelon, and other crops thus, reducing vigor or killing the plants. Remember: Some species are more serious in garden that is recently sodden. Wireworms can be detected with baits (grain or potato) buried underground before planting.
6. Diamondback Moth
Plutella xylos tella Plants attacked: Cabbage, cauliflower, broccoli, radish, mustard Type of damage: Larvae eat many small holes on underside of leaves, giving plant a shot-hole appearance. Some feeding does not go entirely through the leaf.
7. Hornworms
Manduca s pp. Family: Sphingidae Plants attacked: Tomato, potato, pepper, eggplant Type of damage: The tomato and tobacco hornworms consume large amounts of green foliage and sometimes fruit. Comments: Easily detected through presence of droppings resembling those produced by rabbits. Can be controlled in home gardens by hand picking. Many hornworms are killed by parasites on the hornworm’s body. 8.Corn earworm or Tomato Fruitworm
Helicoverpa zea Family: Noctuidae Plants attacked: Many, including corn, tomato, bean, pepper, okra, eggplant Type of damage: Corn earworms feed on the marketable portion of each vegetable crop that it attacks, often making them unusable. Remember: Home gardens may wish to cut the damaged tips off sweet corn ears or plant extra to compensate for losses.
9. Striped Cucumber Beetle
A calymma vi ttatum Family: Chrysomelidae Plants attack: Cucurbits (cucumber, squash, gourd, watermelon) Type of damage: Larvae feed on roots and underground stems. Adults may destroy newly emerged plants. On older plants, beetles feed on leaves, shoots, and stems. The beetles transmit a bacterium that causes bacterial wilt to cucumber and cantaloupe. Remember: Only a short period of feeding is necessary to transmit the bacterium, so plants must be protected from beetle feeding, Protecting plants with row covers before bloom will prevent beetle feeding and disease transmission, but be sure to remove them when flowers appear.
10. Spotted Cucumber Beetle
Diabrotica undecimpunctata howardi Family: Chrysomelidae Plants attacked: Cucurbits, bean, pea, potato, beet, asparagus, eggplant, tomato, corn, cabbage Type of damage: Larvae feed on roots of corn, beans, alfalfa, and many grasses. Adults feed on foliage and also transmit bacterial wit of cucurbits to cucumber and cantaloupe.
Building blocks in insects . Identify the statements below and fill in each block with a letter that corresponds with your answer. The number of blocks determines the number of letters of the correct answer. Again write your answer in you test notebook. 1 2 3 4 5 6 7 8 9 10
1. The first letter of the beginning of an insects’ life. 2. Are all insects harmful? 3. The initial letter of the 3 body divisions of an insect. 4. That stage of an insect when they are in their cocoon. 5. The last stage of an insect’s life. 6. The body division with 3 segments where the 3 pairs of legs are found. 7. They are characterized with 3 body divisions, 3 pairs of legs, with or without wings. 8. The specialized mouthpart of a chewing insect. 9. A needle like structure to suck plant juices, nectar and blood. 10. The protective covering of an insect body which is hard. Exclude the first letter.
C. Matching type. Match column A to column B. Write the letter of your answer in your test notebook. COLUMN A
1. 2. 3. 4.
Entomology Insect control Pathogen Sucking insects 5. Biting insects or chewing insects 6. Metamorphosis 7. Roguing 8. Disinfection 9. Protection 10. Disease
COLUMN B
a. building or placing of effective barriers to control spread of diseases. b. the study of insects and their c. causal organisms of diseases d. any abnormal condition that will affect the normal function of plant parts e. the changes in the life of an insect f. the removal of a diseased plant g. the direct killing of the pathogen while it is on its host or in the environment of the host. h. group of insects that sucks plant juices i. group of insects that eat parts of the plant. j. a small invertebrate animal having three body divisions, three pairs of legs and usually with wings .
The plant disease A disease is an abnormal condition that injures the plant or causes it to function improperly . A plant disease can be identified or diagnosed through the characteristic/s or seen by manifestation of diseased (symptoms) and the presence of visible structures (signs) produced by the pathogen. The causal agent (pathogen) may be either a living agent (biotic) or nonliving agent (abiotic). Biotic agents have the ability to enter and colonize plant parts and other plants. When disease increases rapidly in a large plant population over time, a serious outbreak occurs (epidemic).( Resouce Manual in IPPM I Vegetables, 2005)
The disease triangle (Resource Manual in IPPM (p.153)
Disease is the result of the interactions between a pathogen and a host in a pathogen and a host in a favorable environment. A disease generally occurs because the host is susceptible, the pathogen is virulent, and the environment is conducive for the disease to grow.
environment
pathogen
host
Examples 0f environmental factors that cause diseases: Temperature. Bacteria grow rapidly at high temperature. Most insects are active and multiply
rapidly in warm temperature. Moisture. High moisture content enhances high germination rate of fungal spores, affects
bacteria in entering into plant tissue cells, and increases fungal spores in number. Wind. Wind disperses fungal spores over distance. Strong winds damage plant tissues,
creating entry points for bacteria. Light wind current is favorable for insects’ movement.
Common causes of plant disease A. Non-living factors (Abiotic)
Non-living factors do not spread from disease-infected plants to healthy plants.
They can be recognized only through their symptoms. Examples: Drying of leaves is due to lack of moisture or due to chemical burn. Yellowing of leaves is due to nutrient deficiency.
They can be avoided by providing nitrogen.
B. Living (Biotic) factors:
A disease may be caused by organisms that spread disease to healthy plants.
The organisms are very small.
Can be recognized by symptoms and signs
Can be managed by destroying or removing the parasitic agent and reducing the number of pathogen and infection rate.
Symptoms and Signs A symptom is the physical expression of change in the appearance and function of the plant. Examples: blights, rots, cankers, gall, necrosis, and spots. A sign is the visible presence of the pathogen such as a fruiting body or as a discharge associated with the disease. Examples: conks, mycelia, ooze
Controlling vegetable diseases As with insect control, disease control is an important phase of vegetable production. Disease control measures begin before the disease is observed in the field. In contrast, measures for controlling insects are usually withheld until insects or their damage is observed. The aims and methods in the control of plant diseases are primarily preventive and secondarily curative. Disease control begins with soil sterilization and seed treatment and continues with applications of fungicides, bactericides or depending upon the causal organism.
Different treatments to control vegetable diseases: 1.
Soil treatment
Using steam or dry heat
Drenching the soil with formaldehyde solution.
Dusting with fungicides
Fumigating the soil.
2.
Seed treatment
Dusting with ceresin, arasan or semesan
Soaking in liquid fungicide
Using hot water treatment
3.
Vegetative treatment. This is done either by spraying or dusting with various fungicides.
4.
Adapting cultural practices that control or minimize plant diseases:
Cultivating and weeding the area with growing plants
Keeping the insects under control
Keeping the [plants vigorous with proper irrigation and fertility
Planting resistant varieties
Burning or burying all infected parts and refuse
Removing the vegetables immediately after harvest
Employing crop rotation
Providing good drainage
To control plant diseases, various means and methods are used. The use of these means and methods are based upon five fundamental principles, namely; exclusion, eradication or extermination, inhibition, protection and production of resistant varieties. a.
Exclusion.
Exclusion aims to keep the causes of the disease from entering and stabling itself in an
uninfected country or locality. The measures used are inspection and quarantine. Inspection is done by examining the suspected plants or plant products for traces of dangerous pathogen so that if such are found the plants may be treated. b.
Eradication or extermination. This may consist of several processes which are listed below.
Sorting – this is done by screening, winnowing, and seed preparation by specific gravity, hand picking
and selecting disease-free seeds or cuttings. This is applied to seeds, nursery and other plants and plant parts used for propagation.
Roguing - The diseased materials are picked and eliminated, buried in the soil to avoid the spread of the disease.
Removal of disease-infected parts – An example of this process is the cutting out of the infected portions of the plant.
Removal of alternate or weed hosts.
Removal of debris – Certain disease causing organisms, for example the Phytopthora disease of eggplant, are found in debris. For this reason it is necessary to practice cleanliness in the farm. Plant materials bearing diseases should be burned or buried deep in the ground.
Cultivation – the mechanical treatment of the soil can destroy the dormant stages of the pathogen or its weed host.
Crop rotation – The object of this method is to starve the pathogen in the soil by withholding its host, or host from the previous crops for several planting seasons.
Disinfection – the operation of directly killing the pathogen while it is on its host or in the environment of the host. This method is used in tubers, seeds, soil, etc. It is maybe done by heat, or with the use of poisonous substances; fungicidal solution, and formaldehyde.
c.
Inhibition or the modification of environment. The aim of this method of control is to hold the pathogen in check by controlling or modifying certain surrounding environmental conditions. For example, damping off in nurseries is controlled by exposing the attacked seedlings to the sun and keeping them in a drier atmosphere.
d.
Protection. The aim of this method is to place effective barriers between the susceptible part of the plant and the pathogen in order to prevent infection. Examples of this method are:
Creation of wind breaks
Selection of sheltered places protected from wind-borne inoculums
Bagging protects the fruits from parasite-bearing insects coming in contact with plants.
Chemical control like spraying of liquid fungicides, or dusting using a fungicide in powder form or dust is applied to the plants
Pictures showing signs/symptoms of diseases of vegetable crops
Bacterial wilt of melon – wilting plant
Downy mildew of melon – leaf symptoms
Downy mildew of luffa – leaf symptoms
Fusarium wilt of cucumber – yellowing and wilting plants
Cottony leak of cucumber – decaying fruit and fungal mycelium
Bacterial soft rot of cabbage – decay of core and internal head tissue
Xanthomonas leaf spot of Chine
Bacterial soft rot – collapsing fruit in the field
Bacterial wilt – vascular discoloration in lower stem and roots
Cercospora leaf spot (Frogeye) – gray-brown circular lesions with light colored center
Pepper mild mottle (PMMV) – mild mosaic in leaves
Tomato mosaic (TOMV) – mild mosaic in leaves
Gray wall (physiological) – gray to brown sunken areas on the fruit surface and brown internal tissue on the fruit walls
Powdery mildew (Leveillula) – leaf yellowing and necrosis evident on the upper surface of leaves
Safety precautions in the use of pesticides (The-Voc CBLM) Practically all of the pesticides commercially available are toxic to man and animals. The people most likely to encounter these hazards are the operators and applicators. Pesticides enter the body in three ways:1) by ingestion or swallowing; 2) by breathing the dusts or vapors; and 3) by absorption through the skin. One form can prove just as fatal as the other, but most cases of poisoning occur through taking in accidentally. Unfortunately children are the most frequent victims of such negligence by the adults. Because of this, all materials should be kept in their original containers and locked up or placed out of the reach of children.
A. Before application 1. Read the label
Determine the target organism.
Identify the rate and time of application.
Wear personal protective equipment (PPE).
Remember the antidotes and other safety measures.
Observe field reentry intervals after treatment.
2. Check the sprayer
Fill the tank with plain water and test the sprayer to be used that there are no leaks or loose connections and the equipment is working properly.
Repair or replace any worn-out or faulty part.
3. Mixing and filling
Extra precaution is necessary when mixing and filling sprayers because pesticides are concentrated.
Wear personal protective equipment.
Open pesticide container carefully to avoid splashes, spills, or drifts.
Keep your head away from the opening of the sprayer.
Wash and change clothes immediately if pesticide is spilled on clothing.
Do not use bare hands in mixing pesticides, nor allow concentrated materials to touch bare skin.
B. During application 1. Wear personal protective equipment. 2. Do not eat, drink, smoke, or blow clogged nozzles with your mouth while applying pesticides. 3. Do not spray when it is windy to avoid pesticide drift. 4. Spray areas near homes in early mornings or evenings when humans, pets and livestock are less likely to be exposed. C. After application 1. Store remaining pesticides properly. 2. Bathe and change clothing after application of pesticides.
3. Stay away from treated field one to two days. This prevents poisoning through contact with treated plants, or inhalation of pesticide fumes.
What to Process Activity 2. Learn about the pesticides used in vegetable gardening and other plants that we eat. How harmful are these chemicals to people? Does rinsing fruit and vegetables with plain water remove the pesticides and make them safe for us to eat. What government laws/ policies/ regulations pertaining to pesticide use?
What to Reflect and Understand Activity 3. . This activity will give you more information about the lesson you have just studied.
Ten Principles of Plant Pathology by John A. Menge and Elinor Pond, Department of Plant Pathology, Unverssity of California, Riverside Plant Pathology is the study of plant diseases including:1) causes, 2) mechanisms by which diseases occur, 3) interactions between plants and disease-causing agents, and 4) controlling diseases. There are a large number of guiding principles in Plant Pathology, which are often difficult to formulate because biology has so few absolutes. Here are 10 principles, which may aid in understanding, diagnosing and controlling diseases of plants.
Principle I - Disease is a malfunctioning of a plant, which results from a
continuous irri tant by a pathog enic ag ent. This definition of plant disease includes organismal causal agents which attack plants such as fungi, bacteria, mycoplasma, viruses, nematodes and parasitic plants.
Principle II - Di s eas e res ults from an interaction of the virulence of the pathog en,
s us ceptibility of the hos t, and the conduc ivenes s of the environment. The concept that plant disease is not caused by a single organism or disease agent is overlooked by most people. Plant disease is instead caused by a combination of three factors: 1) a pathogen, 2) environmental conditions, and 3) host response. This concept is visualized by the “disease triangle” in which the three factors, pathogen, environment and host make up the three sides of a triangle and the are of the triangle is the amount of disease produced in the plant(Fig.2). The disease triangle shows visually that a very weak and inefficient pathogen could cause substantial disease if the environment is conducive or if the host is extremely susceptible.
Principle III - Conditions which favor plant growth and health commonly favor
disease.
One of the most common misconceptions among horticulturists and the public is that healthy
plants are somehow more resistant to plant disease and so abundant water and fertilizer are often treated as pesticides to insure plant health. While this may be true for weak or opportunistic plant pathogens it is not true for most competent pathogens. For example, high levels of nitrogen fertilizers, which result in rapid growth of plants, are often prescribed to improve plant health. Not only does this commonly result in ammonia toxicity, but high levels of nitrogen are known to exacerbate disease by many pathogens such as
Rhizoctonia,
Pythium,
Phytophthora,
Fusarium,
Armillaria,
Sclerotium,
Pseudomonas,
Corynebacterium,powdery mildews, rusts, cyst nematodes and many others.
Principle IV - Overwatering and underwatering plants both exacerbate dis eas e. Perhaps the most common plant problems, for most home owners and for ornamental plants in general, results from improper watering. Plants damaged by growing in water saturated soil can often be diagnosed by the foul hydrogen cyanide odor of the soil. Plants which are chronically drought stressed usually have leaves which have brown necrotic tips or edges. However, most people are not aware that overwatering or underwatering can predispose plants to disease. Predisposition is the environmental modification of plant resistance making the plant more susceptible to disease
Principle V - The realistic way to manage plant disease is through an integrated
management strategy that includes: 1) cultural practices, 2) epidemiology, 3) res is tant varieties, 4) chemical pesticides , and 5) biolog ical control. Plant diseases are often extremely difficult to control and require a flexible approach which utilizes all of the tools available to us. In most situations, utilizing several methods to control disease is more practical and efficient than relying on a single method. An example of cultural control is mulching which will often reduce root rot caused by Phytophthora. Epidemiology is the study of factors affecting the outbreak and spread of infectious disease. Familiarity with the epidemiology of a pathogen will show
how factors such as temperature, rainfall, wind and leaf wetness affect its ability to produce spores, spread and inf ect its host. Knowledge of epidemiology will often lead to the formulation of “models” which forecast or predict disease. Simple models such as rainfall for longer than 24 hours when the temperature is above 24C requires a fungicide spray are often the best and most useful means of both controlling a disease and reducing the amount of fungicide applied. Resistant varieties are often the ultimate way to control disease. However, the resistance may break down and for many ornamental plants resistance is simply not available. Chemical pesticides are often the only effective way to control disease. New IPM (Integrated Pest Management) guidelines stress using only enough pesticide to control the disease and to constantly look for ways to reduce pesticide applications. Biological control of plant pathogens is not as advanced as it is in insect control. While there are substantial numbers of biological control agents on the market, most are not very efficacious for control of diseases in the field.
Principle VI - A major approach to dis ease control is inoculum reduction. Inoculum is the pathogen or its parts which can cause plant infection. Reduction of inoculum is a two pronged approach, which includes inhibiting the pathogen and reducing its spread. Inoculum can be fungal spores or survival structures, bacteria, or virus particles, but it can also be plant debris, infested soil, infected roots, diseased parts of perennial plants, insect vectors or infected fruit or vegetative organs. Inoculum must be reduced or eliminated to control disease. Inoculum can be moved by wind, wind-blown rain, water, insects, seeds, infected transplants, animals, humans, equipment and pruning tools. Care to prevent movement of inoculum to the plant will effectively reduce the inoculum and control disease.
Principle VII - Wood decay organisms result in wind damage and breakage in
trees. While this principle seems self evident, it is amazing how many homeowners are more interested in saving their tree than in the potential danger to their house, car or their own person. Wood decay organisms often damage only the dead, central heartwood portion of the tree causing the tree to be hollow. The tree shows very little outward signs of the damage since one or two outer rings of the trunk can conduct all the water and nutrients to sustain the tree. Fruiting bodies of the wood decay fungi, which resemble brackets or shelves, are signs that the tree may in danger of breaking and falling over.
Principle VIII - Epidemics of introduced (invasive) species are more severe than epidemics of endemic s pecies . Notices in airports and borders plead with visitors not to bring in plant material which may harbor new diseases. However despite our best efforts new diseases are introduced and because our plants have little resistance to introduced species and there are no competitors or predators to keep their numbers low, an epidemic occurs which is very difficult to control.
Principle IX - Quarantine is often the bes t method for c ombating dis eas e. This principle is really a corollary of Principle VIII, and is I am afraid being ignored today in this atmosphere of free trade.
Principle X - Do no harm. This is really the first rule of plant pathology. Certainly our state and federal governments are ignoring this rule when they downgrade our quarantine system. However, this rule is really aimed at the farmer or homeowner who tries to control disease without really understanding plant pathology. Diseases are commonly exacerbated by overwatering and over fertilization by well meaning gardeners. Plant pathologists term efforts to control disease which result in worse disease as boomerang effects. A classic example of the boomerang effect occurs if a soil-borne pathogen reinvades fumigated soil. Without natural enemies to reduce its spread it often becomes far worse than it would have been before fumigation. Disease tradingis another term which results when one disease is controlled but another is exacerbated by the same treatment.
What to Transfer Activity 4. Learn more about organic gardening. Talk with someone who raises vegetables organically. What is involved? What are the problems with organically raised food? Are these foods safe to eat? Why do they typically cost more that of non-organic foods.
SUMMARY/SYNTHESIS/FEEDBACK Bio-fertilizers are microbial inoculants or groups of microorganisms which in one or another make nutrients available from sources which those plants cannot tap themselves. The nitrogen bio-fertilizers include Rhizobium (for legumes), the blue-green algae (BGA), Azospirillium, Azotabacter, and Frankia ( for non-legumenous trees). The P bio-fertilizers are made up of bacteria and fungi that solubilize unavailable forms of phosphorus, thus converting tehm into available forms. Efficient phosphor-bacterial isolates have been identified as Pseudomonas striata, P. rattonis and Bacillus polymyra. Among the fungi, the efficient P solubilizers have been observed among the Aspergillus and Penecillium goups. The mcorrhizae constitute another group of bio-fertilizers in that they increase the absorption of P from the soil and P-fertilizers.
Perform mulching According to the Resource Manual in IPPM in Vegetables (p.39-42) m ulch is any material or substance spread on the ground to protect plant roots from heat, cold or drought or to keep fruit clean. Mulches can be classified as inorganic or organic. Inorganic mulches include plastics and other non-plant materials; whereas, organic mulches include straw, compost, sawdust and similar materials. Plastic is the only inorganic mulch used in vegetable garden.
Importance of mulching 1.
Mulching the area will prevent erosion. A thin layer of mulch on the soil surface specially sloping areas reduces the washing away of soil particles by flowing water.
2.
It conserve water. Therefore, mulching is most important when it is impossible to adequately irrigate newly seeded areas.
3.
Proper mulching in summer months keeps the soil cooler. Soils covered with organic mulches keep soil below the mulch layer cooler in summer.
4.
Organic mulches enrich the soil as they decay and provide a better environment for plant growth. Soils that have high organic matter are easier to till and better suited to vegetable gardening.
5.
Mulches help plants by gradually increasing soil fertility. Organic mulches when turned under and decomposed build the soil’s organic matter content.
6.
Most mulch also provide excellent weed control. Mulches do not prevent weed seeds to germinate. However, weed seedlings are blocked by mulch thick enough to exclude light. According to P.D. Sangalan and R.L. Sangalan Practical Guide to Organic Garde ning (p. 48-49) enumerate other importance of mulching as follows:
7.
Promotion of bacterial life. It has been shown the microlife of the soil particularly in the upper layer is promoted by a mulch layer.
8.
A better uptake of nutrients, particularly potash. The reasons are: a. the potash content of the mulch layer. The potash in the plant straw occurs in readily available form and easily moves with the rainwater into the root zone. b. Soils under the mulch layer remains more wet, thus checking potash fixation. c. The potash from fertilizer application remains more available for the plants, owing to the more favorable moisture condition of the upper layer of the soil. d. The feeding roots of the plants under a mulch layer grows into the most superficial soil layer where, especially in clay soils the greater part of the fertilizer potash is absorbed.
9.
Mulching reduces the work of cultivation around the growing plants, thus, cuts the labor of weeding to almost nothing.
Garden with plastic mulch Mulch materials A lot of materials can be used as m ulch materials. Examples are: 1.Compost is generally the best mulching material for home and school gardens. It is usually free of weed seeds and is inexpensive. They are just present in the backyard. Apply at least 4 inches as mulch layer. 2.
Straw is short lived and coarse textured. More straw is needed for the same effect as compost or lawn clippings. Place at least 3-inch thick of this material for better effect.
3.
Sawdust is a common mulch material that can be easily collected. If well manage, it can be a good mulch. It can result in a temporary, but sharp, decrease in soil nitrogen. Add a small amount of garden fertilizer to the soil after applying sawdust directly to a garden. Even better, add nitrogen to sawdust, then compost it before spreading it on your garden.
4.
Plastic is effective mulch if used properly. Use black plastic in the summer to warm the soil. Black plastic keeps light from the soil and prevents weeds from growing. Clear plastic warms the soil, but weeds can grow beneath the plastic. Plastic mulches can be used nt only once, but, the disadvantage is plastic mulch cannot be turned under the soil at the end of the season.
5.
Quality harvests are obtained when the soil is covered with mulch materials. Mulches prevent the direct contact of garden fruits with the soil keeping them clean and other damages.
Selection of mulch materials
The following should be considered in selecting mulch materials. 1.
Cost of the material. Do not spend money on mulching material when there are suitable and readily available materials in your locality.
2.
The crop you plan to mulch. Never use material from the crop that is to be protected. Example – do not use potato vines from spring crop to mulch fall potatoes because the possibility of the disease is increased.
3.
When the mulch is to be used. Select light-colored mulch during the summer to reflect heat. Use dark-colored mulch in early rainy season to help warm the soil and to permit earlier planting and hasten early growth.
SUMMATIVE ASSESSMENT Direction:
Read and understand the questions carefully and select the best answer by writing the LETTER in your test notebook. 1.
Plants need food to nourish their parts. Which of the following refers to any organic or inorganic materials of natural or synthetic origin which is added to the soil to suppy certain elemens essential for plant growth? a. Fertilizer c. Macroelements b. Trace elements d. Microelements 2. The amount of fertilizer to be applied depends on many factors. Whih of the following is the least observed factor regarding rate of fertilizer application? a. Nutrinet requirement of the plant b. The manner of appluying the fertilizer c. Environmental factors particularly rainfall d. The capability of the farmer to supply the neededfertilizer 3. Which of the following methods of fertilizer application is most applicable ito seedlings to have their starter solution applied? a. Fertigation b. Broadcasting c. Foliar application d. Localized application 4. There are several ways of determining soil fertility which are simple and complicated. This method observes any abnormal appearance of the growing plant which maybe caused by a deficiency of one or more nutrient elements. a. Soil analysis b. Plant tissue analysis c. Field fertilizer trials d. nutrient deficiency symptom 5. Which one is the primary function of nitrogen? a. Hastens maturity b. Aids in seed formation b. Forms and transfers starch c. d. Gives dark green color to plant 6. When the fertilizers are applied in scattered manner over the surface of the land, the method of fertilization is a. side dressing b. broadcasting c. foliar application d. band or row or localized placements 7. Which of the following is NOT a method of determining soil fertility? a. soil analysis b. field fertilizer trials c. nutrient deficiency symptom d. foliar application of fertilizer 8. In order to conserve soil fertility, the following methods should be practiced EXCEPT a. composting, b. application of organic fertilizer c. practice cover cropping and mulching d. practice green manuring and intercropping
