Stubble Decomposition (In Situ) of Two Rice Varieties Through Microbial Inoculation

Stubbles of rice varieties Mahsuri (Taichung 65/Mayang Ebos 6080/2) and Ranjit (Pankaj x Mahsuri) were treated after harvest of the crop by spraying microbial inoculums – laboratory culture of cellulose degrading microorganism (CDM) or yogurt (commercial) or mixture of CDM and yogurt with glyphosate (0.205% solution in water) either with sugar or without sugar for in situ decomposition. Microbial inoculums were also sprayed with glyphosate and urea, and the treatments were compared with control plots, viz., untreated, water spray, and glyphosate spray. At the end of the fourth month, Mahsuri showed faster decomposition than Ranjit with corresponding decreases in dry biomass and percent organic carbon of the stubbles following treatment with CDM culture or yogurt with glyphosate solution. Addition of sugar to the spray mixture was not significant. The reduction in dry biomass and organic carbon in stubble was up to 61.1 and 45.3% in Mahsuri and up to 47.1 and 46.4% in Ranjit, respectively, after 4 months of the treatments. Significant increase in diversity of weeds in terms of number of species was observed in plots with higher stubble decomposition.