Not Available

Not AvailableImproved understanding of the process of carbon (C) stabilization is critical to managing emissions fromagricultural soils and optimizing crop yield. We assessed soil organic C (SOC) stability and nitrogen (N)dynamics in a long-term fertilization experiment (started in 1972) conducted at three different locationsin India (Jabalpur-Vertisol, Palampur-Alfisol and Ranchi-Alfisol). We measured soil organic C (SOC), Cpools and stocks in the treatments of no fertilization as control, inorganic fertilization as NPK and inte-grated fertilization as NPK + farm yard manure (FYM). Quantification of different SOC pools was done bya procedure of acid hydrolysis followed by a long-term (247 days) incubation study. Based on crop yieldand C storage, NPK + FYM was the best treatment for improving crop productivity and SOC sequestration.Integrated fertilization for 38 years increased SOC across sites. In the NPK treatment, additional C input(3–9 times higher) in the form of root biomass did not significantly change C pools. Application of FYMin addition to NPK enhanced the acid non-hydrolysable fraction of SOC across sites. Stability of SOC sig-nificantly influenced N dynamics in soil and the availability of N in soil is correlated with the amount ofC in the acid-hydrolysable pool (R2= 0.64, p = 0.01) but not with SOC (R2= 0.12, p = 0.01). Long-term useof chemical fertilizers did not significantly affect soil total N content.Not Availabl

Not Available

Not AvailableGlobal climate change is anticipated to have a tremendous influence on crop productivity and nutrient cycling in legume-based cropping systems. The effect of long-term application of manure and fertilizers on the dynamics of soil organic carbon (SOC) pools and soil physical properties was studied in a soybean (Glycine max Merr. L)–wheat (Triticum aestivum L.) system. The temperature sensitivity of C pools and the alterations in microbial composition were determined at 25, 35, and 45 ◦C. Higher levels of microbial biomass C (MBC) and nitrogen (MBN), water soluble carbon (WSC), acid hydrolysable carbohydrates (AHC), particulate organic matter carbon (POMC) and nitrogen (POMN) were observed in the NPK + FYM at a depth of 0–15 cm. Irrespective of the treatment, micro aggregates (53–250 m) were a major aggregate size class, comprising 45–57% of the total soil aggregates, followed by macro aggregates (250–2000 m at 37.8–45%). Microbial respiration rate increased by 13.9% in most recalcitrant pools (<53 m) at 45 ◦C than at 25 ◦C. Furthermore, data on labile C (A0) revealed a 4.9–55.4% increase in the substrate pools and a 10.5–32.5% increase in mineralization rate (k) with these treatments at 25–45 ◦C in 250–2000 m aggregates. AHC and POMC content decreased by 23–37% and 12–23% of SOC, respectively, when the temperature was raised from 25 to 45 ◦C. It is concluded the gradual depletion of nutrients, structural degradation and changes in microbial composition might have collectively contributed to the decline in crop yields. It was suggested that temperature has a strong effect on C mineralization, depending on the types and extents of substrate utilization. Seasonal rainfall, maximum and minimum temperature and SOC had jointly explained 12–41% of variation in soybean production in NP, NPK and NPK + FYM treatments. However, balanced use of NPK plus FYM is an important management option to arrest the decline of crop yield.Not Availabl