Data collected from various scales of measurements of soil, hydraulic, vegetative, and meteorological variables in the Xilin River Basin, Inner Mongolia.
Description
The dataset comprises long-term observations of soil temperature and moisture at various scales within the Xilin River Basin, along with soil data from sampling points. The data is collected at five sites within the Inner Mongolia grassland: with long-term grazing exclusion since 1979 (UG79), short-term grazing exclusion since 1999 (UG99), continuous grazing (CG), heavy year-round grazing (HG), and moderate winter grazing (WG).Data collection includes: i) At the Pedon scale, the field in situ monitoring of soil temperature and moisture was conducted from 2004 to 2008 (UG79, UG99, CG, HG, and WG sites) and from 2016 to 2020 (UG99, UG79, and CG plots). ii) At the field scale, during the growing seasons from 2004 to 2008, a regular sampling grid (105 meters × 135 meters, sampling interval 15 meters, secondary grid interval 5 meters, totaling 100 points) was established using differential GPS and UTM systems (horizontal resolution 2 meters, vertical resolution 0.1 meters). Soil water content (SWC), hydraulic conductivity (K), water drop penetration time (WDPT), shear strength (SS), soil organic carbon (SOC) concentration, bulk density (BD), and soil texture data were collected in areas with five different grazing intensities.iii) At the watershed scale, a stratified two-stage sampling scheme was designed, using land use and topography as stratification variables, and selecting 30 sampling points. A 12-day soil survey was conducted starting from July 1, 2007. This comprehensive dataset provides valuable insights into soil, vegetation, and meteorological aspects, revealing the impact of grazing on the Mongolian grasslands.
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Starting from June 2004, at the UG79, UG99, CG, HG, and WG sites, Theta probes were horizontally inserted at three depths (5, 20, and 40 centimeters) to measure soil moisture content, and platinum resistance temperature probes (Pt-100) were used to measure soil temperature at five depths (2, 8, 20, 40, and 100 centimeters). Data were recorded by an automatic data logger at 30-minute intervals in summer and 1-hour intervals in winter. Some monitoring continued until the end of 2008.Since May 2014, continuous real-time monitoring has been conducted in Inner Mongolia grazing grasslands under different grazing intensities (UG79, UG99, CG) for soil thermal and moisture conditions (depths: 10, 30, 50, 70, and 100 cm) using an automated monitoring instrument (EM50 data recorder connected with ECH2O 5TE sensor from DECAGON, USA) recording at 30-minute intervals. At each site, three replicate profiles were installed 15 meters apart from each other. At the initial installation, undisturbed soil samples (cylinder 100 cm³, n=7) were taken from three corresponding layers of 4-8, 18-22, and 40-44 cm for laboratory measurements of physical properties including water retention curves, hydraulic conductivity, bulk density, and soil mechanical stability. Van Genuchten parameters were fitted using the RETC software based on water retention curves. Our measurements were conducted in five field plots of different grazing intensities UG79, UG99, WG, CG, HG. In each area, a regular sampling grid(area of 105 m × 135 m, a sampling spacing of 15 m and sub-grid spacing of 5m, 100 points) was set up using a differential GPS with the UTM system (a lateral resolution of 2 meters and vertical resolution of 0.1 meters) for geostatistical analysis. In each plot, the volumetric soil water content (HH2 moisture meter) (0-6 cm) was measured weekly during the growing season starting in 2004 and continued for 3 years when rainfall events exceeded 3 mm. Additionally, the following field measurements were conducted: shear strength (hand-held anemometer), water drop penetration time (time taken for a 0.5mm³ water droplet to enter the soil), and hydraulic conductivity (Mini-disk infiltrometer, at a suction value of 0.5cm). From June to August 2004, undisturbed soil samples were collected three times at each grid point using stainless steel cylinders (100cm³) for laboratory analysis. A total of 50 different time points were measured. A design-based, stratified two-stage sampling scheme was employed for field sampling, using land use and soil type as stratifying variables. Six land use categories were combined with eight soil types to create 10 different environments, from which 30 locations were randomly selected. Field surveys and sampling began on July 1, 2007 (early in the growing season) and lasted for 12 days. At each sampling point, a profile was excavated, and undisturbed soil samples were collected from each soil layer using a 100cm³ steel cylinder.