Direct and Residual Effect of Pressmud Cakes in Rice-Wheat Cropping System

A greenhouse experiment was conducted to study the effect of sulphitation pressmud cake (SPMC) and carbonation pressmud cake (CPMC) to determine the fertilizer equivalence of pressmud cakes (PMC) for rice and the residual effect on succeeding wheat crop. Application of either type of cake was beneficial for the both rice and wheat crops. The SPMC was better than the CPMC. The fertilizer equivalence of 10 t ha⁻¹ of SPMC was 50 per cent while that of CPMC was 28% of fertilizer recommendation for rice. The residual effect of CPMC on wheat showed improvement in its efficiency but was lower than the SPMC. Increase in organic C, available P, K and Zn in soil were more pronounced from the SPMC than from the CPMC. However, the use of CPMC showed slight increasing trend in pH and CaCO₃ contents.