Effect of long term fertiliser and manure application on Soil Nitrogen Fractions in an Inceptisol under Fingermillet: Maize cropping sequence

Abstract

A field experiment was conducted to study the effect of continuous manuring and fertiliser application on soil nitrogen fractions in sandy clay loam soil (Inceptisol) during 2019 -20 in the ongoing Long-Term Fertilizer Experiment with Finger millet - maize cropping sequence. The results revealed that the nutrient availability in soil and nutrient uptake were significantly influenced by FYM along with 100% NPK application. The soil received graded levels of fertiliser from 50% to 150% increased the soil inorganic and organic nitrogen fractions. Comparing the treatments, the treatment which received 100% NPK +FYM recorded the highest values for different fractions of inorganic N (Exchangeable NH4-N, Exchangeable NO3-N & Fixed - N) and organic N fractions (Total hydrolysable N, Total hydrolysable NH4 - N, Hexosamine N, Amino acid N, Unidentified hydrolysable N and Unidentified non hydrolysable N) followed by 150% NPK. Other graded level fertiliser treatments such as 100% NPK, 100% NP and 100% NPK + Hand Weeding, 100% NPK (S free) were on par with each other and the lowest value was observed in control treatment. Significant positive correlations were obtained between N fractions and yield, total N uptake, available N and organic carbon.