Effects of different land use types on grassland soil and vegetation in the agropastoral transition zone of northern China
摘要
As terrestrial ecosystems of the world, grassland ecosystems play a vital role in maintaining climate stability. However, the effects of different land use types on grassland health are currently unclear. To investigate the effects of various land use types on grassland health, the Xilamuren grassland (with an area of approximately 1000 km2) in the Inner Mongolia Autonomous Region, China, which features multiple land use types, was chosen as the research subject. Response of soil physicochemical properties and vegetation characteristics under four land use types, including enclosure, grazing, reclamation, and tourism, has been examined. Moreover, grassland health and individual soil fertility components were evaluated. The main results are as follows: In terms of vegetation properties, the enclosure land use type exhibited the highest above- and belowground biomass values of 248.50 g⋅m− 2 and 143.56 g⋅m− 2, respectively. In contrast, the above- and belowground biomass values were lowest for the tourism land use type, at 20.78 g⋅m− 2 and 23.33 g⋅m− 2, respectively. In terms of soil properties, the soil organic matter content (12.90 g·kg− 1), total soil nitrogen content (0.73 g·kg− 1), and saturated soil moisture content (30.93%) were relatively high under the enclosure land use type, while the bulk density was lowest (1.25 g·cm− 3). The reclamation land use type demonstrated relatively high total phosphorus (0.53 g·kg− 1) and total potassium (15.48 g·kg− 1) contents. Among vegetation traits, both the enclosure and reclamation land use types revealed an aboveground biomass that was higher than the belowground biomass, whereas the tourism and grazing land use types exhibited the opposite pattern. In terms of soil properties, the values of chemical characteristics (organic matter, total nitrogen, total phosphorus, and total potassium contents) decreased with increasing soil depth. However, the variations in soil physical properties differed across land use types. With increasing depth, the soil saturated water content decreased, whereas the soil bulk density increased under the enclosure and reclamation land use types. Conversely, under the grazing and tourism land use types, these parameters indicated opposite trends. Grassland health decreased in the order of enclosure, reclamation, grazing, and tourism land use types. Under the tourism land use type, the organic matter and total nitrogen contents in the 0–10 cm soil profile had already reached Category V deficiency levels, indicating severe degradation. The findings of this study provide valuable reference data for grassland development and utilization.