Sensitivity of Labile Carbon Pools and Soil Organic Carbon Stocks to Organic and Mineral Fertilization Across Foothill Himalayas

While soil organic carbon (SOC) is instrumental in soil fertility and soil productivity, thus offers an extremely imperative part in sandy soils of foothill Himalayas, scarce documentation has been surfaced regarding the short-term SOC changes and carbon stocks. The current study was conducted over two consecutive years (2016 and 2017) to assess the soil organic carbon changes under varied fertilization practices in black gram monoculture. A total of 13 treatments were replicated thrice in randomized block design in sandy loam soil. The results revealed that application of farmyard manure @ 2 t ha-1 (FYM) and inorganic fertilization under T13 recorded the highest labile carbon (LC), particulate organic carbon (POC), microbial biomass carbon (MBC), and soil organic carbon. Further, it has recorded lowest bulk density, while the treatment T2 marked the highest value for bulk density. A significant and positive relationship was observed among different carbon fractions. The sensitivity index (SI) of MBC, POC, KOC and SOC varied from 3.14 to 15.37%, 2.42 to 5.06%, 1.87 to 17.40% and -0.40 to 4.45%, respectively and differences were greatest in FYM treatments. The results inferred that application of FYM holds a prime prominence and should be preferred in the nutrient management to boost soil fertility and properties of soils, for maintenance of soil quality and crop production.