Long term effects of fertilization on carbon and nitrogen sequestration and aggregate associated carbon and nitrogen in the Indian sub-Himalayas

Abstract

An understanding of the dynamics of soil organic carbon (SOC) as affected by farming practices is imperative for maintaining soil productivity and also for restraining global warming by CO 2 evolution. Results of a long-term (30 year) experiment in the Indian Himalayas under rainfed soybean (Glycine max L.)-wheat (Triticum aestivum L.) rotation was analyzed to determine the influence of mineral fertilizer and farmyard manure (FYM) application at 10 Mg ha -1 on SOC and total soil nitrogen (TSN) stocks and distribution within different aggregate size fractions. Fertilizers (NP, NK and NPK) and FYM in combination with N or NPK were applied before the soybean crop every year and no nutrient was applied before the wheat crop. Results showed that addition of FYM with N or NPK fertilizers increased SOC and TSN contents. The overall gain in SOC in the 0-to 45-cm soil depth interval in the plots under NPK ? FYM treatment over NPK was 17.18 Mg C ha -1 in 30 year. The rate of conversion of input C to SOC was about 19% of each additional Mg C input per hectare. SOC content in large size aggregates was greater than in smaller size aggregates, and declined with decreased aggregate size. Thus, long-term soybean-wheat rotation in a sandy loam soil of the Indian Himalayas sequestered carbon and nitrogen. Soil organic C and TSN sequestration in the 0.25-to 0.1-mm size fraction is an ideal indicator of long-term C and N sequestration, since this fraction retained maximum SOC/TSN stock.

Carbon sequestration and Jerusalem artichoke biomass under nitrogen applications in coastal saline zone in the northern region of Jiangsu, China

“…1), which was consistent with earlier studies (Fontes et al, 2010;Zhou et al, 2006). However, an excess nitrogen application increased the risk of degradation of soil, air and water resources (Bhattacharyya et al, 2010). In addition, the present study showed that dry matter accumulation in Jerusalem artichoke showed a decreasing tendency when an excess of nitrogen fertilizer was applied.…”

Long-term application of fertilizers on chemical and biological properties of an Alfisol

“…The organic carbon content varied form 4.82 to 6.26 g kg -1 in the treatments which was slightly higher as compared to the original value due to its addition through roots or farm yard manure in T 8 and T 10 treatments. Higher soil organic carbon content was noted on combined application of FYM and mineral fertilizers (Bhattacharyya et al, 2010). Soil organic C content was improved from the start of the experiment in the unfertilized plots due to C addition through the roots and crop residues, higher humification rate constant, and lower decay rate (Kundu et al, 2002 andEnke Liu et al, 2010).…”

Soil Enzyme Activities, Microbial Diversity and Available Nutrients Status of an Alfisol under Long Term Fertilization

“…Significantly higher organic carbon content was recorded in 100 % NPK+FYM+lime (0.70) followed by 100 % NPK+lime (0.60 %). Higher soil organic carbon content was noted on combined application of FYM and mineral fertilizers (Bhattacharyya et al, 2010). Lower OC contents were observed in control (0.48 %) and in 100 % N alone (0.50 %).…”