Division of Soil Science and Agricultural Chemistry, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, 193201, India.
Division of Soil Science and Agricultural Chemistry, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, 193201, India; Division of Agronomy, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India.
J Environ Manage. 2022 Oct 15;320:115811. doi: 10.1016/j.jenvman.2022.115811. Epub 2022 Aug 11.
The Himalayan ecosystem is critical for ecological security and environmental sustainability. However, continuous deforestation is posing a serious threat to Himalayan sustainability. Changing land-use systems exert a tenacious impact on soil carbon (C) dynamics and regulate C emissions from Himalayan ecosystem. Therefore, this study was conducted to determine the changes in different C pools and associated soil properties under diverse land-use systems, viz. natural forest, natural grassland, maize field converted from the forest, plantation, and paddy field of temperate Himalaya in the surface (0-20 cm) and subsurface (20-40 cm) soils. The highest total organic carbon (24.24 g kg) and Walkley-black carbon contents (18.23 g kg), total organic carbon (45.88 Mg ha), and Walkley-black carbon stocks (34.50 Mg ha) were recorded in natural forest in surface soil (0-20 cm depth), while soil under paddy field had least total organic carbon (36.45 Mg ha) and Walkley-black carbon stocks (27.40 Mg ha) in surface soil (0-20 cm depth). The conversion of natural forest into paddy land results in 47.36% C losses. Among the cultivated land-use system, minimum C losses (29.0%) from different pools over natural forest system were reported under maize-filed converted from forest system. Land conversion causes more C losses (21.0%) in surface soil (0-20 cm depth) as compared to subsurface soil. Furthermore, conversion of forest land into paddy fields increased soil pH by 5.9% and reduced total nitrogen contents and microbial population by 28.0% and 7.0%, respectively. However, the intensity of total nitrogen and microbial population reduction was the lowest under maize fields converted from the forest system. The study suggested that the conversion of natural forest to agricultural land must be discouraged in the temperate Himalayan region. However, to feed the growing population, converted forest land can be brought under conservation effective maize-based systems to reduce C loss from the intensive land use and contribute to soil quality improvements and climate change mitigation.
喜马拉雅生态系统对生态安全和环境可持续性至关重要。然而，持续的森林砍伐正对喜马拉雅地区的可持续性构成严重威胁。土地利用方式的改变对土壤碳（C）动态具有顽强的影响，并调节喜马拉雅生态系统的 C 排放。因此，本研究旨在确定不同土地利用系统下不同 C 库的变化及其相关土壤特性，这些土地利用系统包括：自然森林、天然草地、由森林转换而来的玉米地、人工林和温带喜马拉雅地区的稻田。在表层（0-20 cm）和次表层（20-40 cm）土壤中，自然森林的总有机碳（24.24 g kg）和沃克-布莱克碳含量（18.23 g kg）最高，总有机碳（45.88 Mg ha）和沃克-布莱克碳储量（34.50 Mg ha）最高。而在表层土壤（0-20 cm 深度）中，稻田下的土壤总有机碳（36.45 Mg ha）和沃克-布莱克碳储量（27.40 Mg ha）最低。将自然森林转化为稻田会导致 47.36%的 C 损失。在人工耕种土地利用系统中，与自然森林系统相比，由森林转换而来的玉米地系统中不同库的 C 损失最小（29.0%）。土地利用方式的转换导致表层土壤（0-20 cm 深度）的 C 损失比次表层土壤更大（21.0%）。此外，林地转换为稻田会使土壤 pH 值增加 5.9%，总氮含量和微生物种群分别减少 28.0%和 7.0%。然而，由森林转换而来的玉米地系统中总氮和微生物种群减少的强度最低。研究表明，在温带喜马拉雅地区，必须阻止将自然森林转换为农业用地。然而，为了养活不断增长的人口，可以将转换后的林地纳入保护性的、以玉米为基础的系统中，以减少集约土地利用造成的 C 损失，并有助于改善土壤质量和减缓气候变化。
