Direct and Residual Effect of Fly Ash,Organic Materials and Mineral Fertilisers on Performance of Rice-based Cropping System under Acid Lateritic Soil Conditions

Abstract

Direct effect of integrated fertilisation with fly ash, organic materials and mineral fertilisers to soil improved or sustained rice grain yield compared with the mineral fertilisers alone. Yields of potato, groundnut and mustard were increased under the residual effect of the integrated fertilisation sources vis-à-vis mineral fertilizers. The combined direct and residual effect of fertilisation sources on cropping sequences revealed that equivalent rice grain yield was higher under the integrated sources as compared to the mineral fertilisers alone. This difference was up to 10% for rice-groundnut sequence while 15% for rice-potato, 19% for rice-mustard, and 27% for rice-sweet potato sequence. Besides crop yield, beneficial residual soil properties in terms of pH, bulk density, organic carbon and available nutrients were noted. An increase in nutrient use efficiency and a save in mineral fertilisers were also feasible under the integrated sources. Residual fertility alone could not produce enough yields. Direct fertilisation in addition to residual fertility increased yields of groundnut pod and mustard seed. Accumulation of heavy metals and radioactive elements in soil and plant remained within safe limits even after application of fly ash at 10 t ha-1 for all the four seasons.