Assessment of Microbial and Enzymatic Activity of Plant-ratoon System in Sugarcane Rhizosphere in Indo-Gangetic Plains of India

A field experiment was carried out on sugarcane plant-ratoon system to develop nutrient management strategies for sustaining soil health, quality and sugarcane production at Research Farm, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar. Trials were conducted to test the efficiency of various fertilizers in sugarcane on solubility of applied inorganic fertilizer during spring season in calcareous soil. The pooled data revealed that number of millable cane (NMC), cane and sugar yield varied significantly due to integrated use of organic and inorganic fertilizer with bio-fertilizer in combination both in plant and ratoon crops. The significant increase in NMC, cane and sugar yield was recorded in the treatments receiving organic and inorganic fertilizer in combination with bio-fertilizer over control. The highest number of NMC (103.0 × 103 ha-1), cane yield (85.8 t ha-1) and sugar yield (11.21 t ha-1) was recorded in treatment T9 i.e 75% NPK of RDF + Acetobacter + PSB + along-with Bio-compost @ 7.5 t ha-1. Similar trend of result was recorded in ratoon crop also, the residual effect of treatment receiving organic and inorganic fertilizer in combination with bio-fertilizer was also maximum pronounced on NMC (92.4 × 103 ha-1), yield (79.6 t ha-1) and sugar yield (9.36 t ha-1). The bio-compost improved overall performance of sugarcane. The uptake of nutrients by plant and ratoon followed the similar trend as cane yield. The treatment receiving RDF along with various biofertilizer significantly improved productivity of sugarcane over control. However, the efficiency of Bio-fertilizer was more pronounced under inorganic treated plots. The reduction in pH and increase in EC, organic carbon and available nutrients (N, P and K) in post-harvest soil was recorded in treatment receiving organics through bio-compost. The enzymatic activities was recorded for glycosidase, urease, acid phosphatase and dehydrogenase activities.