Comparative and Interactive Effects of Organic and Inorganic Amendments on Soybean Growth, Yield and Selected Soil Properties

The absolute use of inorganic fertilizers, growing of exhaustive crops, nutrient losses with runoff and leaching under mountainous sub humid conditions has declined the soil fertility and productivity. The field experiment was carried out to study the comparative and interactive effect of organic and inorganic amendments on soybean growth, yield and soil properties. The experimental design was randomized complete block design (RCBD) with three replications. The treatments combination were control (no amendments); 100 kg N ha-1from urea nitrogen (UN100); 100 kg N ha-1 from poultry manure (PMN100); 100 kg N ha-1from sawdust (SDN100); 100 kg N ha-1 from UN + PM (UN50 + PMN50); 100 kg N ha-1 from UN + SD (UN50 + SDN50); 100 kg N ha-1 from PM + SD (PMN50 + SDN50); 100 kg N ha-1 from UN + SD + PM (UN50 + SDN25 + PMN25). Results indicated higher crop growth in UN50 + SDN25 + PMN25. However, SDN100 showed lower growth but higher than control.UN100had statistically higher grain yield (1322.7 kg ha-1) and it was non-significant with UN50+PMN50and UN50+ PMN25+SDN25.Nitrogen uptake (156.55 kg ha-1) was higher in UN100,UN50+ PMN50and UN50+ PMN25+SDN25.Post-harvest soil properties showed the minimum pH in SDN100andhigher organic matter in organic and integrated applications. The higher phosphorus contents were in UN50+PMN50. This study showed that SD and PM combined with urea have potential in soybean growth enhancement, yield increase and in improvement of soil properties.