know your fertilizers before you use them; Attributes and determination of Fertilizers

June 15, 2020 Agrovista

know your fertilizers before you use ; Attributes and determination of Fertilizers

Know your fertilizers before you use them. Attributes and determination of Fertilizers

Fertilizers differ in nutrient content, a form of the nutrient, water solubility, mobility, etc. Nitrogen and potassic fertilizers have much higher salt indices than phosphatic fertilizers and are detrimental to germination when placed in contact with the seeds. Phosphatic fertilizers are more efficient than those containing more water-soluble phosphorus than citrate-soluble fertilizers.

How to Increase the efficiency of fertilizer ;

The time of application also plays an important role in using fertilizer efficiently. Nitrogenous fertilizers being mobile have greater chances to escape, whereas phosphorus and potassium fertilizers are less movable. The crops are grown in the rainy season and are given in split doses so that loss is minimized. The foliar application has been found very beneficial. Slow-release fertilizers are becoming popular and suitable in Indian conditions.

How to make fertilizer Selection;

The fertilizers are selected based on the following recommendations:

A) How to Select Nitrogenous Fertilizers for Crop Application

Table of Contents

1) In paddy ammonium fertilizers, viz. ammonium sulphate, ammonium chloride, and Urea should be used; Calcium ammonium nitrate and diammonium phosphate may also be applied
2) In acid soils or calcium-deficient soils, continuous application of ammonium sulphate, urea, ammonium chloride and ammonium sulphate nitrate should be avoided or lime is given before fertilizer application.
3) In winter or rabi season, all nitrogenous fertilizers are equally effective; therefore, the fertilizers should be selected based on cost, availability, and ease of application.
4) For top dressing, sodium nitrate and urea are the best suitable fertilizers.
5) In sandy soil or well-aerated soils, split doses of nitrate fertilizers are given. The application of sodium nitrate in the rainy season is avoided.

B) How to Select Phosphate Fertilizers for Crop Application

1) Acidic soils are most suitable for the application of rock phosphate and basic slag.

2) Superphosphates contain water-soluble phosphates; thus the nutrient in these fertilizers is available to plants even in the young stage, when it is required most. Superphosphates should be applied just before sowing, as phosphorus requirements in the early stage of plant growth are high.
Recommended dose of superphosphate shall be applied before sowing of paddy, wheat, jowar, cabbage, cauliflower, potatoes, etc. In long-duration crops like sugarcane, the second split dose may be given with the first earthing up.
3) Superphosphates should be used in neutral to alkaline soils but not in acidic soils. In acidic soil, the water-soluble phosphorus changes to insoluble iron and aluminum phosphates; hence, it is unsuitable in acidic soils.
4) Basic slag, dicalcium phosphate, and bone meal are particularly suitable for acidic soils as low pH converts citrate-soluble phosphoric acid to water-soluble monocalcium phosphate.
5) Phosphatic fertilizers like ammonium phosphate, nitro phosphate, monocalcium phosphate, dicalcium phosphate, Rhenamia phosphate, and Kota phosphate have available phosphorus and can be applied in any crop to be grown in neutral soil.
5) Phosphatic fertilizers should be placed near the root zone or in the soil layer, where the roots are most active as phosphates are least mobile. (vii) In fruit trees like citrus, guava, apple, etc. it should be placed deep with a deep cultivator.

B) How to Select Potassic Fertilizers for Crop Application

Muriate of potash is suitable for all crops. It can be applied at any time, but the early stages of the crop require this nutrient the most. Hence, it is applied before sowing. It is soluble and mobile.

On application to soil, it dissociates to ions and gets attached to or adsorbed on the soil complex. As such, this fertilizer, though soluble in water, is not easily lost by leaching.