Ex.No:15
Study of fertigation equipments and practicing fertigation fertigation
Fertigation
Fertigation is a method of fertilizer application in which fertilizer is incorporated within the irrigation water by the drip system. In this system fertilizer solution is distributed evenly in irrigation. The availability of nutrients is very high therefore the efficiency is more. In this method liquid fertilizer as well as water soluble fertilizers are used. By this method, fertilizer use efficiency is increased from 80 to 90 per cent. Fertilizers commonly used in fertigation N – P2O5 – K2O content
Solubility (g/l) at 20 C
34-0-0 21-0-0 46-0-0 12-61-0 18-46-0 0-0-60 13-0-44 0-0-50 0-52-34 0-52-0
1830 760 1100 282 575 347 316 110 230 457
N%
P2O5 %
K 2O %
Polyfeed
19
19
19
Polyfeed Polyfeed Polyfeed
20 11 16
20 42 8
20 11 24
Polyfeed Polyfeed MAP
19 15 12
19 15 61
19 30 0
Multi-K MKP SOP
13 0 0
0 52 0
46 34 50
Name
Ammonium nitrate Ammonium sulphate Urea Monoammonium phosphate Diammonium phosphate Potassium chloride Potassium nitrate Potassium sulphate Monopotassium phosphate Phosphoric acid Specialty water soluble fertilizers Name
N fertigation
Urea is well suited for injection in micro irrigation system. It is highly soluble and dissolves in non-ionic form, so that it does not react with other substances in the water. Also urea does not cause precipitation problems. Urea, ammonium nitrate, ammonium sulphate, calcium ammonium sulphate, calcium ammonium nitrate ar e used as nitrogenous fertilizers in drip fertigation.
P fertigation
Application of phosphorus to irrigation water may cause precipitation of phosphate salts. Phosphoric acid and mono ammonium phosphate appears to be more suitable for fertigation. K fertigation
Application of K fertilizer does not cause any precipitation of salts. Potassium nitrate, Potassium chloride, Potassium sulphate and mono potassium phosphate are used in drip fertigation. Micro nutrients
Fe, Mn, Zn, Cu, B, Mo could be used as micro nutrients in drip fertigation. Fertigation equipments
Three main groups of equipments used in drip system are : • • •
Ventury Fertilizer tank Fertilizer pump
Ventury
Construction in the main water flow pipe causes a pressure difference (Vaccum) which is sufficient to suck fertilizer solution from an open container into the water flow. It is very easy to handle and it is affordable even by small farmers. This equipment is most suitable for smaller area. Fertilizer tank
A tank containing fertilizer solution is connected to the irrigation pipe at the supply point. Part of the irrigation water is diverted through the tank diluting the nutrient solution and returning to the main supply pipe. The concentration of fertilizer in the tank thus becomes gradually reduced. Fertilizer pump
The fertilizer pump is a standard component of the control head. The fertilizer solution is held in non-pressurised tank and it can be injected into the irrigation water at any desired ratio. Therefore the fertilizer availability to each plants is maintained properly.
Cost of fertigation equipments Sl.No.
Fertigation devices
Cost (Rs.)
1.
Ventury type
1200
2. 3.
Fertilizer Tank Injectors
3000 12000
Fertilizer Tank – cost Rs 3500
Ventury Rs 1250
Fertilizer pump Rs. 12,000
Concept of fertigation •
•
•
Fertigation is the judicious application of fertilizers by combining with irrigation water. Fertigation can be achieved through fertilizer tank, venturi System, Injector Pump, Non-Electric Proportional Liquid Dispenser (NEPLD) and Automated system. Recommended N & K @ of 275 and 112.5 kg. ha-1 may be applied in 14 equal splits with 15 days interval from 15 DAP.
• • •
25 kg N and 8 kg K2O per ha per split. Urea and MOP (white potash) fertilisers can be used as N and K sources respectively Fertigation up to 210 DAP can also be recommended
Advantages of Fertigation •
•
•
• •
• • •
•
Ensures a regular flow of water as well as nutrients resulting in increased growth rates for higher yields Offers greater versatility in the timing of the nutrient application to meet specific crop demands Improves availability of nutrients and their uptake by the roots Safer application method which eliminates the danger of burning the plant root system Offers simpler and more convenient application than soil application of fertilizer thus saving time, labour, equipment and energy Improves fertilizer use efficiency Reduction of soil compaction and mechanical damage to the crops Potential reduction of environmental contamination Convenient use of compound and ready-mix nutrient solutions containing also small concentration of micronutrients.
Element Nitrogen
Phosphorus
Fertilizer Liquid Ammonium nitrate Ammonium sulphate Urea Super phosphate water
Limitation None To be avoided in uses of water having Ca > 70 ppm None Colloidal particles well screened
Phosphoric acid
pH of water regulated Very dilute solution pH regulated
Potassium Iron, Zinc
Liquid potassium nitrate Liquid potassium chloride Chelated compound
Avoid micronutrient deficiency in the soils None Avoid when water contain high chloride >300 ppm none
Water saving, yield and profit under drip and drip fertigation systems
Crops
Yield (t/ha) Water Saving Conventional Drip (%)
Profit (Rs/ha) Drip+ Conventional Fertgn
Drip
Drip + Fertgn
Banana
35
26
30
37
81000
98000
120000
Sugarcane Tomato
29 32
120 45
160 56
207 65
30000 56000
47000 77000
68000 95000
Practicing Fertigation In Sugarcane Pit method of sugarcane planting under drip fertigation system Technology • •
• • • •
• • •
•
•
•
Pit to pit spacing - 1.5 x 1.5 m Number of pits/ha - 4,444 pits Pit diameter - 0.9 m Pit depth - 0.38 m Number of budded setts / pit- 32 (single budded setts) Fill the pits to a depth of 15 cm with compost and native soil and mix it well. Place the healthy setts in circular fashion leaving 10 cm from the outer boundary of the pits with equal spacing between each setts and cover the setts with soil. On 50 to 60 days after planting give partial earthing up by sliding the soil from the outer boundary of the pit and full earthing up should be given leaving a depression of 2.5 cm from the ground level at 90 to 100 days after planting Fertilizer dose - 275:62.5:112.5kg NPK/ha The entire phosphorous dose can be applied as basal at the time of planting The nitrogen and potassium as urea and MOP (white potash) should be applied through fertigation system in 14 equal splits starting from 15 DAP upto 210 DAP Drip design -lateral to lateral spacing 3.0 m (alternate rows) 8 mm micro tubes on either side of the lateral to a length of 1.0 m with one 8 LPH drippers / pit Irrigation - daily or in alternative days
Benefits • • • • • • •
Higher cane yield Multi rationing is possible Suited in problem soils More water saving System maintenance is easy Less labour for after cultivation operations Higher net return
Economics
Pit planting of cane in 1.5 m x 1.5 m pit spacing registered the highest net return of Rs.1, 19,649 ha-1 and 1, 55,982 ha-1 with in BCR of 2.26 and 3.31 in plant and ratoon crops respectively compared to the net return of Rs.1,16,650 and 1,27,360 registered in conventional method of cane cultivation in plant and ratoon crops .
