Nutrient Management :: Fertigation

Nutrient Management :: 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. Content on this page requires a newer version of Adobe Flash Player. Fertigation Micro Irrigation and Fertigation Fertilizer efficiencies of various application methods Nutrient Fertilizer use efficiency (%) Soil application Fertigation Nitrogen 30-50 95 Phosphorous 20 45 Potassium 50 80  Advantages of fertigation Nutrients and water are supplied near the active root zone through fertigation which results in greater absorption by the crops. As water and fertilizer are supplied evenly to all the crops through fertigation there is possibility for getting 25-50 per cent higher yield. Fertilizer use efficiency through fertigation ranges between 80-90 per cent, which helps to save a minimum of 25 per cent of nutrients. By this way, along with less amount of water and saving of fertilizer, time, labour and energy use is also reduced substantially. Water saving, yield and profit under drip and drip fertigation systems Crops Water Saving (%) Yield (t/ha) Profit (Rs/ha) Conventional Drip Drip+ Fertgn Conventional Drip Drip + Fertgn Banana 35 26 30 37 81000 98000 120000 Sugarcane 29 120 160 207 30000 47000 68000 Tomato 32 45 56 65 56000 77000 95000 Fertilizer used in fertigation Urea, potash and highly water soluble fertilizers are available for applying through fertigation. Application of super phosphorus through fertigation must be avoided as it makes precipitation of phosphate salts. Thus phosphoric acid is more suitable for fertigation as it is available in liquid form. Special fertilisers like mono ammonium phosphate (Nitrogen and Phosphorus), poly feed (Nitrogen, Phosphorus and Potassium), Multi K (Nitrogen and Potassium), Potassium sulphate (Potassium and Sulphur) are highly suitable for fertigation0 as they are highly soluble in water.   Fe, Mn, Zn, Cu, B, Mo are also supplied along with special fertilisers. Fertilizers commonly used in fertigation Name N – P2O5 – K2O content Solubility (g/l) at 20 C Ammonium nitrate Ammonium sulphate Urea Monoammonium phosphate Diammonium phosphate Potassium chloride Potassium nitrate Potassium sulphate Monopotassium phosphate Phosphoric acid 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 Specialty water soluble fertilizers Name N % P2O5 % K2O % Polyfeed 19 19 19 Polyfeed 20 20 20 Polyfeed 11 42 11 Polyfeed 16 8 24 Polyfeed 19 19 19 Polyfeed 15 15 30 MAP 12 61 0 Multi-K 13 0 46 MKP 0 52 34 SOP 0 0 50 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 are 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. Fertilizer Tank 3000 3. Injectors 12000 Economics of drip irrigation system The initial investment in drip irrigation system is mainly depends upon the spacing of crops.  The initial cost will be almost 20-25 thousand rupees per hectare for wider spacing crops such as coconut, mango, grapes and for orchard crops. The initial cost is approximately 50-70 thousand rupees per hectare for close spacing crops such as sugarcane, banana, papaya, mulberry, turmeric, tapioca, vegetables and flower crops.