Effect of sulphur on soil biological properties, residual fertility and yield of aerobic rice grown under aerobic rice-wheat cropping system in Inceptisols

Abstract

Abstract Aim: Rice productivity is stagnant or declining due to imbalanced nutrition, including deficiency of Sulphur. In India about 44% soils (out of total cultivated land) is sulphur deficiency. Various sources of Sulphur fertilizers are available, but gypsum and phosphogypsum can be better options for the farmers. The main aim of this study was to improve the soil fertility, soil microbial properties and rice yield with application of Sulphur. Methodology: The combination of two Sulphur sources (gypsum and phosphogypsum) at two levels i.e.30 and 60 kg ha-1 and control (no.S) were applied to rice crop and three levels of sulphur ( elemental sulphur) i.e. 0, 15 and 30 kg ha-1 were applied to succeeding wheat grown under rice-wheat cropping system. Microbial biomass carbon and microbial activities in terms of Fluorescein Diacetate (FDA) hydrolysis, Dehydrogenase and Arysulphatase activity were estimated in different treatment by standard procedure. Organic carbon N, P, K and S were estimated for residual fertility after harvest of rice crop. Rice grain yield was recorded at 14% moisture content. Result: Direct and residual effect of Sulphur application increased the wheat grain and straw yield. Sulphur application increased 8.2 to 12.8% (microbial biomass carbon), 16.9 to 32.3% (Arysulphatase Sulphur) than the other sulphur treatments. However status after two years of cropping system was improved by 6.4, 12.7, 5.2 and 9.7% with Sulphur application through gypsum @ 30 and 60kg S ha-1 phosphogypsum @30 and 60kg S ha-1 , respectively. Interpretation: Sulphur also essential as microbial-S for the micro-orgainism. Hence, Sulphur application increased the microbial biomass carbon and arysulphatase activity. Application of Sulphur through gypsum or phosphogypsumin soil improved the soil microbial properties and Sulphur @ 30kg ha-1 through gypsum can increased the rice yield by 10% over control (no Sulphur).