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-preca gram while cropping of sorghum + vegetable cowpen-rice-soybean added highest amount of P. Irrigating the rice crop at 5 cm depth on the day of disappearance of ponded water and irrigating the khorif and summer crops at 0.75 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.

Key words : Crop residues, Component crops, Nutrients added