Integrated nutrient management in rice (Olyza sativa)- - rice cowpea (Vigna unguiculata) sequence under humid tropical Andaman Islands

Abstract

A field experiment was conducted during 1993-94,1994-95 and 1995-96 to study the effects of integrated nutrient management in a rice (Oma sativa) - - rice cowpea [Vigna unguiculata (L.) Walp.] sequence on crop productivity, soil fertility and economics. Combined use of 50% NPK + 50% poultry manure significantly increased the grain yield of first rice crop (74%) and second rice crop (79.8%) over the control. The effect of 50% NPK + 50% FYM and NPK dose alone was also comparable. Application of FYM and poultry manure alone or combined with 50% NPK had signifi- cant residual effect on the pod yield of cowpea. The pH and EC values did not change significantly. The highest increase in soil organic carbon (0.68%) was obtained from FYM application over initial value of 0.45%. The available N increased to 276 kgtha under 50% NPK + 50% poultry manure treatment over initial value of.220 kglha. The application of poultry manure alone increased the available P (15 kg) and K (121 kg) over initial status, 11 and 112 kglha respectively. Highest net returns (Rs 23,083lha)and benefit cost ratio (1.67) were obtainedfrom application of 50% NPK+ : 50% poultry manure.