Effect of Integrated use of Bio-Compost and Nitrogen on Productivity and Soil Properties of Sugarcane Plant–Ratoon System in Calcareous Soil

Abstract

A field experiment was conducted for three consecutive seasons on sugarcane plant–ratoon system during years 2008–2014 at crop research farm, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar to evaluate the integrated effect of bio-compost and nitrogen on productivity and soil properties in calcareous soil. The distribution of different fractions of soil nitrogen viz. exchangeable NH4 +–N, hydrolysable NH4 +–N, hexoseamine-N, amino acid-N, unidentified-N and status of total-N were determined. The significant increase in number of millable cane (NMC) and cane yield was recorded in the treatments receiving bio-compost in combination with fertilizer-N over control both in plant and ratoon crops. The highest number of NMC (90.7 × 103/ha), cane yield (74.14 t/ha) and sugar yield (7.72 t/ha) of plant was recorded in treatments receiving 50% N through bio-compost +50% N through inorganic fertilizer. The residual effect of treatment receiving 50% N through bio-compost and 50% N through inorganic fertilizer was also pronounced on NMC (83.90 × 103/ha), yield (69.70 t/ha) and sugar yield (7.42 t/ha). Further, application of 100, 125 and 150% N through bio-compost resulted in gradual decrease in yield of plant, but on the contrary, it increased by 6–7% in ratoon crop as compared to plant cane. The uptake of nutrients varied significantly. The highest sugar yield (plant and ratoon) was recorded in treatment receiving 50% N through bio-compost +50% N through inorganic fertilizer. Addition of bio-compost either alone or in combination with inorganic fertilizer-N significantly improved organic carbon and availability of nutrients (N, P, K and S) with reduction in bulk density of post-harvest soil over control. The highest organic carbon (6.2 g/kg) and N (281.6 kg/ha), P2O5 (26.3 kg/ha), K2O (129.5 kg/ha) and S (33.6 kg/ha) was recorded in treatment receiving 150% N through bio-compost. The bulk density varied from 1.33 to 1.42 g/cm3. The EC increased while pH decreased with increasing levels of bio-compost. The significant improvement in microbial population was also recorded in bio-compost treated plots. After third crop cycle of sugarcane cropping system, application of bio-compost either alone or in combination with fertilizer significantly increased all the forms of N-fraction over control. Among the various N-fractions, non-hydrolysable-N was the dominant N-fraction.