Fencing for grazing exclusion and grazing are common land-use methods in the semi-arid areas of the Loess Plateau in China, which have been widely found to change grassland soil organic carbon (SOC); however empirical studies that evaluated driving factors of soil carbon (C) stocks under the different land use are still weak. In this study, we investigated soil physicochemical and soil respiration (Rs) in the fenced and grazed grassland, to study the soil C stock variations and the main driving mechanism of soil C accumulation. The results showed that bulk density (BD), soil moisture content (SMC), and soil porosity (SP) had no significant difference between fenced and grazed grassland. Fencing increased the SOC, total nitrogen (TN), and C/N ratio, and significantly increased the aboveground biomass (AGB), belowground biomass (BGB), and the amount of soil large macro-aggregates in the topsoil layer (0-10 cm), and the soil stability was improved. Meanwhile, grazing increased soil temperature (ST) and Rs. The soil C stock in the topsoil layer (0-10 cm) of fenced grassland was significantly higher than that of grazed grassland. The soil C/N ratio, BD, and MWD explained large proportions of the variations in soil C stocks. Our results indicate that fencing can improve the stability of soil structure, and reduce Rs, then increase soil C stocks, which is an effective way to improve soil C stocks of grassland ecological in semi-arid areas of northwest China.

The burning of crop residues (traditionally called ‘Parali’) has recently become a hot topic in India because it is presumed to be one of the reasons for abnormally high levels of air pollution in New Delhi, the capital city of India, after harvesting of Kharif crops during winter months. During the process of finding out a feasible solution for quick disposal of agricultural waste in a safer way, a novel method has been developed by the authors in which crop residue is converted into a useful product, biochar, which can be applied back to the fields for amendment of soil. It not only reduces the introduction of harmful gases into the environment but also improves the physical and chemical properties of the soil. This method is very simple and can be adopted by an individual farmer without much investment and technical skills. Many studies have been conducted on the factors involved in the production and use of biochar as a soil amendment; but in India, not much work has been carried out yet, as it is relatively a new concept in terms of using biomass for biochar production and application. Although biochar is not a new product, it has drawn the attention of researchers and other stakeholders in the near past because of its usefulness in improving the physical and chemical properties of the soil and at the same time reducing greenhouse gas emission, which is one of the biggest challenges for the modern world to protect the environment.