Contribution of organic matter and chemical nitrogen on soil microbial biomass and sugarcane early-growth dry matter

A pot experiment was conducted to ascertain the contribution of OM and chemical N on soil microbial biomass formation and sugarcane early growth dry matter yield. During tiller initiation phase, soils amended with OM and chemical N significantly increased mineral N over control, except sugarcane trash that encouraged N immobilization in soil. But, sugarcane trash amended soil with the increasing levels of chemical N up to 160 kg N ha1 showed significantly higher microbial biomass C and N. With the exception of sugarcane trash amended soils, addition of OM with the increasing levels of chemical N significantly increased number of tillers/plant, plant height, yield of shoot and root, N content in shoot and N uptake by plant over control. However, press mud with 107 kg N ha1 produced significantly higher number of tillers/plant (12.7), dry matter yield of shoot (193 g/plant) and root (245 g/plant), and N uptake (1.7 g/plant) by sugarcane among all other treatments.