Thakur, S.K.Priyadarshi, Rashmi2023-10-192023-10-192021D/SS/115/2017-18https://krishikosh.egranth.ac.in/handle/1/5810199396Sugarcane is a long duration and nutrient-exhaustive crop. The excessive and imbalanced use of chemical fertilizer has raised problems like deterioration of soil health. The soil organic carbon content is continuously declining due to the nonaddition of organic matter which is a matter of great concern. Restoration of organic matter is thus, needed for maintaining soil health and improving productivity through the addition of organic amendments. A field experiment was therefore, conducted during 2018-20 at Dr. Rajendra Prasad Central Agricultural University Pusa (Bihar) to assess the “Effect of organic amendments on soil carbon pool parameters, cane productivity and juice quality of sugarcane in calcareous soil”. The experiment was laid out in randomized block design with eight treatments and thrice replications. The organic treatments comprised of FYM @ 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. The results revealed that the application of organic amendments significantly increased the soil organic carbon content & stock and different organic carbon pool parameters in post-harvest soil. The percent increase in soil organic carbon content and stock due to the addition of the organic amendments over control ranged from 22.75 - 47. 25 and 6.49 - 23. 50 % after harvest of sugarcane ratoon, respectively. The significantly higher value of watersoluble carbon (49. 89 - 56. 22), water-soluble carbohydrate (193.07 - 203.63) soil microbial biomass carbon ( 238.80 - 243.15 mg kg-1) and CO2 evolution ( 52.56 - 65.04 mg 100 gm-1 soil day-1) was recorded in organic treated plots over control after harvest of the ratoon crop under sugarcane plant - ratoon system. In organic treatments, a significant decrease in bulk density (4.1 - 6.8 %) and increase in porosity (5.1 - 8.4%) were registered over control in post- harvest soil after the ratoon crop. The available N, P2O5 & K2O content in soil significantly increased due to the addition of the organic amendments over control which ranged from 236.25 - 266.28, 24.41 - 34.40 & 117.24 - 124.41 and 249.48 - 272.58, 30.15 - 40.18 & 119.26 - 127.05 kg ha-1, in sugarcane plant and ratoon crops, respectively. A positive and significant correlation was obtained between carbon pool parameters and soil quality parameters. The application of different organic amendments significantly increased the number of tillers & millable cane and cane yield in sugarcane plant and ratoon crops. However, a non-significant effect on cane germination, height, girth and single cane weight were observed. The addition of organic amendments showed higher cane and sugar yield which was at par with RDF. The plant and ratoon cane yield in organic treatments varied from 43.69 - 85.86 and 35.87 - 77.27 t ha-1 and sugar yield from 4.92 -10.70 & 4.06 - 10.56 t ha-1, respectively. The N, P & K uptake by sugarcane plant and ratoon crops varied from 200.01 - 292.7, 17.9 - 19.8 & 200.5 - 278. 9 and 152.0 - 255.6, 10.6 - 15.9 & 170.0 - 249.9 kg ha-1, respectively. The maximum B: C ratio in sugarcane plant and the ratoon crops was registered in the treatment receiving green manuring with moong (2.29 & 2.98) which was at par with treatments receiving sugarcane trash @ 10 t ha-1 (2.13 & 2.71), vermicompost @ 5.0 t ha-1 (1.93 & 2.37) and farmyard manure @ 20 t ha-1 (2.18 & 2.92), respectively. Thus, the application of FYM @ 20 t ha-1 or vermicompost @ 5.0 t ha-1 or sugarcane trash @ 10 t ha-1 or green manure with moong was beneficial for restoration of soil carbon stocks, maintaining soil health, enhancing cane & sugar yield and getting economic returns under sugarcane plant-ratoon system in calcareous soil of Bihar.EnglishThesis