Productivity of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system as affected by its residue management and fertility levels

A field study on crop-residue management conducted from 1993 to 1997 on rice (Oryza sativa L.) -wheat (Triticum aestivum L. amend. Fiori & Paol.) system at CCS HAU Rice Research Station, Kaul revealed that rice /grain yield was significantly superior with the incorporation of residues of both rice and wheat crops to their burning and removal. But in wheat the trend was reverse during the early years. During winter season (rabi) 1993-94, grain yield of wheat was found to be the lowest (35.8 q/ha) on incorporation of residues of both the crops. Burning of residues gave highest grain yield (43.7 q/ha), closely followed by their removal (42.8 q/ha). However, this deleterious effect on grain yield was recuperated in the subsequent years, thereby registering the highest grain yield of 49.2 q/ha, with the incorporation of residues in fourth wheat crop (1996-97). The influence of burning (44.7 q/ha) and removal (43.0 q/ha) of residues on grain yield of wheat remained at the lowest level amongst the 7 treatments on residue management in rabi 1996-97. The average productivity of the system was the highest (114.6 q/ha/year) where the residues of both the crops were incorporated, which was 6.0 and 6.2 q/ha/year higher than from their burning and removal respectively. Higher fertility (150 + 60 + 25 kg N, P2O5 and ZnSO4/ ha) registered significantly higher grain yield than lower (100 + 40+25 kg N, P2O5 and ZnSo(4)/ha). Organic carbon and total nitrogen in the soil increased with the incorporation of crop residues but decreased with their burning.