Abstract

Field experiments were carried out during 1986-'88 with five rice based cropping systems, two irrigation regimes and two fertilizer levels at the Agricultural College and Research Institute, Madurai, Tamil Nadu. Appreciable amount of crop residue was added by sorghum + vegetable cowpea -rice-soybean system. Addition of N and K through crop residue was greatest in rice rice-green gram while cropping of sorghum + vegetable cowpea- rice- soybean added highest amount of P. Inigating the rice crop at 5 cm depth on the day of disappearance of ponded water and irrigating the khurif and summer crops at 11,75 and 0.60 IW/CPE ratios, respectively, added higher amount of crop residue in the second year. Similarly more N through crop residue in the first year, while addition of P was more in the second year was also observed. Application of N, P and K as per soil test recommendations resulted in higher crop residue addition in first year and fertilizer level with more N and K through crop residue in first year.

Keywords: Crop residues, Component crops, Nutrients added