Integrated management of green manure, farmyard manure, and nitrogen fertilizer in a rice‐wheat rotation in northwestern India

Sesbania (Sesbania aculeata) is an important green manure crop for wetland rice, and it can fix large amounts of N2. Farmyard manure (FYM) is traditionally a valuable source of nutrients, but it can meet only a part of the N requirement of the rice crop. Limited information is available on the nitrogen fertilizer value of green manure and complimentary and synergistic effects of green manure, FYM, and nitrogen fertilizer. A field experiment was conducted during 1989–1993 to evaluate the effectiveness of sesbania green manure and FYM (77–105 kg N ha‐1) applied either alone or in combination with green manure for wetland rice. Sesbania accumulated 90 to 135 kg N ha‐1 in 52 days. During each year, the total N addition to green manure and FYM amended plots was adjusted to 150 kg N ha‐1 by applying additional N through urea. The grain yield of rice increased significantly up to 150 kg N ha‐1. Green manure‐N proved as efficient as urea‐N in increasing rice yield. The availability of N from FYM was much lower th...