1. Controlling the alkalinity of irrigation water is possible. 

2. Efficient application of Rock Phosphate and all other phosphatic fertilizers is possible.

3. Increased availability of nutrients to plants is possible.

4. Reduction in the leaching of chemical nutrients is possible. 

Select the correct answer using the code given below: 

(a) 1,2 and 3 only 

(b) 1, 2 and 4 only 

(c) 1, 3 and 4 only 

(d) 2, 3 and 4 only

9. Ans: c

Explanation:

Fertigation: 

It 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.

Advantages of fertigation:

• Nutrients and water are supplied near the active root zone through fertigation which results in greater absorption by the crops and reduction in leaching of chemical nutrients.
• 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, alkalinity due to irrigation can also be controlled.

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, but use of all other phosphatic fertilizers is not possible.
• 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.

Hence statement 2 is incorrect and 1,3 and 4 are correct.

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