(a) Nitrogen
Application of nitrogen in split doses has become a well established practice as urea is a highly leaching fertilizer. Two third or half of the quantity should be applied at the time of sowing and remaining one third or half quantity should be top dressed at first irrigation in medium or heavy soils. On sandy soils, top dressing should be made in two or three instalments if heavy dose of nitrogen is to be applied. Under rainfed conditions full dose of N should be placed into the soil before sowing.
All nitrogenous fertilizers presently available in the market are equally effective for wheat under normal soil conditions. In calcareous soils (containing free lime) and in strongly alkaline soils, 10-30 % of applied nitrogen may be lost through ammonia volatilization, if urea or other ammonical fertilizers are used for top dressing. In such cases CAN (Calcium ammonium nitrate or Kisan Khad) should be preferred to urea.
