Dynamics of applied nitrogen in acidic soils of Kuttanad

Abstract

The present study on ‘dynamics of applied nitrogen in acidic soils of Kuttanad (Karappadadom soil)’ was conducted at the College of Horticulture, Vellanikkara, Trichur from January 1986 to December, 1986. A total of six materials viz., urea, ammonium sulphate, neem coated urea, neem coated ammonium sulphate, gypsum coated urea and rock phosphate coated urea were used as N sources. The experiment included limed and ulimed treatments of these sources at two moisture regimes. The results of the study proved that the rate of nitrification was very low in Karappadom soil and that there was no appreciable conversion of NH + 4 – N to NO -3 N. It also showed that the coated fertilisers performed better than the uncoated fertilisers in this soil. EC and PH of the soil increased on submergence. Eh and PH of the soil were negatively correlated. Data on various growth and yield characters of the rice variety Jyothi showed that, nitrogen recovery was higher with coated fertilizers than with uncoated fertilisers. Rock phosphate coated urea gave maximum grain yields, however in the presence of lime its efficiency was reduced drastically.