Gosal, S. K.Jaspreet Kaur2016-12-252016-12-252014http://krishikosh.egranth.ac.in/handle/1/92735A field experiment was carried out to study the impact of non sustainable factors (green manure and plant density) on soil microbial biomass, soil enzyme activities and NPK of soil in order to achieve environment-friendly agriculture and promote the sustainable development of rice (Oryzae sativa L.) crop. Maximum bacterial population (159 × 108cfu/g of soil), methanotrophic population (176 × 104 cfu/g of soil), actinomycetes population (52.5 × 104cfu/g of soil) and alkaline phosphatase activity (21.9 mg/g of soil/hr) was observed in the treatment having green manure (15t/ha) + 44 plants/m2+ recommended NPK whereas diazotrophic population (57.61 × 105cfu/g of soil), fungal population (25 × 103cfu/g of soil), dehydrogenase activity (50.0 µg TPF/g of soil/hr) and urease activity (855 µg/ g of soil/hr) was observed maximum in treatment with green manure (15t/ha)+33plants/m2+ recommended NPK. Biochemical characterization of 18 different methanotrophic bacteria isolated from rice crop revealed that all isolates were positive for citrate production; negative for indole and VP test whereas most of them were positive for methyl red and negative for H2S production. Maximum soil nitrogen (206.9 Kg/ha) was observed in treatment having green manure (15t/ha) + 33plants/m2+ recommended NPK whereas soil potassium (212.0 Kg/ha) and phosphorus (35.8 Kg/ha) were observed maximum in treatment having green manure (15t/ha) + 44 plants/m2+ recommended NPK. Increased plant height (103.8cm) and yield attributes like effective tiller (386/m2), number of spikelet (18), filled grain panicle-1 (136), thousand grain weight (22.4g), straw yield (86.65 Q/ha) and grain yield (73.25 Q/ha) were observed in same treatment. Significantly positive effects of green manure were observed on microbial biomass, enzyme activity, NPK content and on yield of rice. The results indicated that increase in plant density did not show negative effect on soil fertility and crop yield. So, application of green manure and increasing plant density effectively increase yield and sustainability of rice cropping system.Thesis