Response of wetland rice to fertilizer N in a soil amended with cattle, poultry and pig manures

Abstract

During the period 1984–1986, field experiments were conducted to study the response of wetland rice to N application in a loamy sandy soil amended with cattle (60 kg N ha −1), poultry (80 kg N ha −1) and pig (75 kg N ha −1) manures. In the absence of urea-N, cattle, pig and poultry manures increased the rice grain yield by 37, 43 and 98%, respectively. Rice yield increased linearly with the application of N, whether or not the soil was amended with organic manure. Urea-N equivalents of cattle, pig and poultry manures varied from 21 to 53, 17 to 65 and 50 to 123 kg ha −1, respectively. Apparent recovery in the crop of N from poultry manure varied from 38 to 82% as compared to 51 to 69% from urea and 10 to 25% from cattle and pig manures. Nitrogen in poultry manure mineralized at a faster rate than that of cattle and pig manures. After the harvest of rice, the three organic manures exhibited residual effects in terms of increased soil organic carbon, available P and yield of succeeding crop of wheat.