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Deep soil carbon (C) plays an important role in the global carbon cycle because it is more recalcitrant and remains in the soil for a longer period. Yet, very few studies have reported the impact of long‐term fertilization on soil organic carbon (SOC) dynamics in deep soil in a rice‐wheat system (RWS). Hence, the objectives of this study were to evaluate the long‐term fertilization impact on carbon sequestration and C pools in RWS in the Indo‐Gangetic Plain (IGP) of India. Application of 90 kg N, 20 kg P and 25 kg K ha−1 through mineral fertilizers (NPK) + green gram incorporation (GR) + 30 kg N ha−1 through farmyard manure (FYM) sequestered more C (25.86 Mg ha−1) in the 0–105 cm soil depth compared with mineral fertilizer alone (1.25 Mg ha−1). The C‐sequestration rate ranged between 0.61 to 1.23 Mg C ha−1 yr−1 under treatments having organic fertilizer and mineral fertilizer, whereas it varied from 0.06 to 0.39 Mg C ha−1 yr−1 in the treatments receiving mineral fertilizer only. Total C and critical C input were 197 Mg kg−1 and 1.94 Mg C ha−1 yr−1, respectively under NPK + GR + FYM treatment. Integrated application of mineral fertilizers and organics in treatments NPK + FYM, NPK + SPM (sulphitation press mud), NPK + GR, NPK + GR + FYM and NPK + CR (crop residue) resulted in higher sustainable yield index of RWS compared to mineral fertilizer alone. We conclude that application of organic material along with mineral fertilizers is essential to mitigate the atmospheric C load through C‐sequestration in deep soils and to attain sustainable RWS productivity in the IGP. [ABSTRACT FROM AUTHOR]

As per international policy agendas on mitigation of greenhouse gas emission, the impact change in land use on soil organic carbon (SOC) stocks is of major concern. There has been no systematic study carried out to estimate SOC pool in the catchment of hydroelectric reservoirs. An assessment of SOC stock along altitudinal gradient was carried out in the catchment of proposed Kotli Bhel 1A hydroelectric reservoir located in Uttarakhand, India. The SOC stocks were found to be decreasing with altitude, ( i.e. soil under high altitude forests having more SOC and vice versa). The SOC map developed from the normalized difference vegetation index also verified the results and allowed for spatially explicit targeting of potential climate change mitigation efforts through soil carbon sequestration. The results also revealed that the alpine forest soil has a greater potential of C sequestration compared to devdar, oak, and chir species found in the catchment. This information will help policymakers or environmentalists to take preventive measures for afforestation of forest species that can sequester more C. [ABSTRACT FROM AUTHOR]

• The soil stoichiometric ratios (C:N:P) were invariant in lower Himalaya. • The studied region has low C:N ratio indicating prospect for N 2 O emission. • Abies species have a higher C sequestration potential and carbon credit. • The findings are helpful to understand nutrient dynamics in forest. Understating of forest functioning is crucial for ensuring the sustainable flow of forest ecosystem services. Climate regulation service of a forest ecosystem can be ensured through emission reduction by increasing carbon sequestration in forests. However, understanding about the functioning of forests for carbon sequestration is constrained due to lack of information on nutrient stocks and stoichiometry of soils of forests of India. Present study focuses to examine the stoichiometry of major nutrients; nitrogen (N), phosphorus (P), carbon (C) of forest soil to understand the dynamics of the forests of Uttarakhand, India. The study also attempted to supplement the information about the soil carbon sequestration potential of important tree species of the forest. Soil samples were collected randomly for the evaluation of physico-chemical characteristics and stoichiometry of forest soil at four altitudinal ranges i.e., <1000, 1000–1500, 1500–2000, and >2000 m a.s.l in the Himalayan region of Uttarakhand, India. The analysis shows that total nitrogen, total phosphorous, and soil organic carbon contents in forest soil were 0.35 ± 0.11%, 0.10 ± 0.04% and 3.36 ± 0.84%, respectively, which increases with altitude. The stoichiometric ratios viz., C:N:P, N:P, C:N, and C:P, and N:P were reported of 51.6:5.4:1, 4.30 ± 2.39, 9.60 ± 1.48, and 41.94 ± 23.35, respectively which were invariant with altitude. The low C:N ratio may be attributed to either increase in the nitrous oxide (N 2 O) emissions with an increase in nitrogen, or low in carbon stock leading to decrease in carbon dioxide (CO 2) and methane (CH 4) emissions. Moreover, the soil C sequestration potential in the forest tree species follow the order of Abies pindrow > Cedrus deodara > Quercus leucotrichophora > Pinus roxburghii. The information of the study would facilitate for broadening the understanding about the soil properties and stoichiometry of forest ecosystem and would provide an aid to forest management besides contributing to the mitigations strategies of the forests. [ABSTRACT FROM AUTHOR]

The carbon stored as soil organic carbon (SOC) and tree biomass is typically the highest carbon pool of the forest and is impacted by degradation and deforestation. The impact of "C" stocks on climate change at different altitudes can have vital implications for the conservation and management of "C" sinks. This study was undertaken in subtropical belt of Tehri Garhwal, Uttarakhand, India, to understand the carbon-storing potential of Anogeissus latifolia tree and its soil properties in three altitudes, i.e., lower (LA: 790–824 m), middle (MA: 825–960 m), and upper (UA: 1168–1212 m), which provide fuel, fodder, and small timber for life support purposes. Results of the study suggested that soil moisture and pH increase with increasing depth and altitude, whereas SOC and soil nitrogen show reverse patterns. Moreover, bulk density (BD) does not follow any trend (i.e., BD increases with soil depth and altitude until 960 m and further decreases with an increase in altitude). Tree density, biomass, and carbon stock reported highest in MA compared with UA and LA because of dense forest and greater tree diameter. Looking into the soil carbon stock, nitrogen, C/N ratio (C/N: < 10), and climatic drivers supportive to microbial degradation, it is concluded that A. latifolia forest has played an important role in carbon reduction and mitigating climate change at regional and global levels. The study will help environmentalists, foresters, and policy-makers to stimulate the combined effect of degradation of forest species on climate change and socioeconomic development at regional and global scale. [ABSTRACT FROM AUTHOR]