Nitrogen Dynamics Under Long Term Lantana Camara (L.) Residue and Fertilizer Application in a Rice-Wheat Cropping System

Long term effects of lantana (Lantana camera L.) residue and fertilizer application were studied on nitrogen (N) fractions in a Typic Hapludalf under rice-wheat cropping at Palampur, India (32°6’N, 76°3’E). After 12 crop cycles, lantana and fertilizer application showed an additive effect on the buildup of different N fractions. Hydrolyzable-N constituted 86% of total organic-N and 84% of total-N. All fractions of N except unidentified-N, non-hydrolyzable-N, and total-N were strongly interdependent and had a positive influence on grain yield and N uptake in rice and wheat crops. Serine+threonine-N was the most important fraction contributing towards grain yield and N uptake in rice and wheat. Fertilizers at 66% of recommendation plus lantana at 10 t ha^?1 maintained higher available-N than that under 100% fertilizers alone; the N content was same as 12 years before. Inclusion of lantana indicated net saving of 33% fertilizers plus higher yields and sustained soil health.