Evaluation of Organic Manure Amendments on Soil Carbon Saturation Deficit in a Rainfed Agriculture System of Himalaya, India.

Organic manure amendments into the rainfed agricultural soil could change the carbon saturation deficit. This study was conducted in the central Himalayan region of India to assess the impact of varying quantities of farmyard manure (FYM) and vermicompost (VC) on changes of soil carbon saturation deficit in the rainfed agricultural system. The experimental plots with three replications and three different amendment rates, such as 15, 30, and 60 Mg ha−1 of FYM and VC were used on the traditional paddy-wheat-finger millet-fallow cropping system. The soil amended with FYM and VC showed significant (p <.05) variations in the soil carbon content, nitrogen content, total microbial activity, β-glucosidase activity, and acid phosphatase activity with an increasing rate of both the manures in each cropping season. The mean soil carbon saturation deficit values varied from 25 to 36% and 19 to 28% in the first year cropping and second year cropping seasons, respectively. Our results demonstrate that the VC amendment was better than FYM for the accumulation of more carbon content in the rainfed agricultural soils of Himalaya, whereas the organic manure amendment rates must be considered for climate change impact mitigation action policy in the future. [ABSTRACT FROM AUTHOR]