Effect of Organic Amendments on Soil Carbon Stock, Yield and Quality of Sugarcane Ratoon

A field experiment was conducted during 2018-20 to evaluate the effect of different organic amendments on yield and quality of sugarcane ratoon in calcareous soil at Crop Research Centre, farm at Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar. The experiment was conducted in randomized block design with 8 treatments viz. control, FYM (farmyard manure) @ 20 t ha-1, biocompost (BC) @ 20 t ha-1, vermicompost (VC) @ 5.0 t ha-1, green manure with moong, sugarcane trash @ 10 t ha-1, FYM + BC+ VC (1: 1: 0.5) @ 20 t ha-1 and recommended dose of fertilizer (RDF) as NPK (170: 50: 60 kg ha-1) and replicated thrice in sugarcane plant-ratoon system. The sugarcane plant crop was taken and after harvest of plant, the ratoon crop was initiated. Addition of organic amendments significantly increased the number of tillers, millable cane and ratoon cane yield which was at par with recommended dose of fertilizer. The cane juice quality was not affected due to different treatments. The mean cane yield (61.7 - 77.1 t ha-1) and sugar yield (4.06-10.56 t ha-1) varied significantly in organic added plots t ha-1 which was found at par with RDF. The sugar yield followed the similar trends of cane yield. The SMBC (soil microbial biomass carbon), CO2 evolution and carbon stocks were significantly higher in organic amendment added plots indicating improvement in soil carbon status. The highest value of CO2 evolution, SMBC and carbon stocks were observed in the treatment receiving FYM+BC+VC in combination (1: 1: 0.5). Organic amendments had beneficial impact on restoration of soil carbon status, cane and sugar yield of ratoon crop of sugarcane in calcareous soil.