Abstract
Farmed catchments have greater temporal and spatial heterogeneity of soil moisture than natural catchments. Increased knowledge about the variation of soil moisture in farmed catchments has important implications for the adoption of appropriate tillage measures for agriculture. The purpose of this study was to determine the spatial and temporal variability of soil moisture as controlled by the environment on a farmed catchment in a typical dry-hot valley (DHV) by integrating geostatistical and redundancy analysis (RDA). We monitored soil moisture in topsoil (0–20 cm) and subsoil (20–40 cm) layers at 51 points on eight occasions from July 2012 to March 2014, and determined the environmental factors of soil particle-size distribution, soil organic matter, slope aspect, slope gradient, elevation, and a topographic wetness index (WI) modified for semiarid conditions at each point. The results showed that, under the influence of high evaporation, soil moisture in the topsoil was significantly lower than that of subsoil in the DHV. In this study, we observed a strong temporal variation of soil moisture, which was influenced by the seasonal variation of crop cover and lagged behind that of rainfall. Relatively high soil moisture levels were found on the watershed divide and hillside sites of the catchment, and lower on the valleyside sites. Different from other studies, RDA analysis indicated that the WI was not correlated with soil moisture in the DHV; instead, clay and sand levels were the dominant control factor of soil moisture in the farmed DHV. We proposed that soil erosion in the DHV could lead to such increases of sand and decreases of clay content, thus influencing soil moisture content. Soil and water conservation measures will be especially important for valleyside sites with steep slopes.
Highlights
Soil moisture is an important component of the complex and interacting continuum soil–vegetation–atmosphere system
We focused on the dry hot valley (DHV) region in Southwest China, and selected a farmed catchment with uniform management practices as case-study areas
We temporal variation of soilofmoisture in the farmed study The catchment catchment was influenced by the seasonal variation of crop cover, and temporal variation of soil was influenced by the seasonal variation of crop cover, and temporal variation of soil moisture lagged moisture lagged behind thatanalysis of rainfall
Summary
Soil moisture is an important component of the complex and interacting continuum soil–vegetation–. The interactions between soil moisture, plants, and atmosphere affect vegetation growth and carbon cycling, especially in arid and semi-arid areas where evaporation is greater than the cumulative rainfall [5]. Soil moisture varies in space, and in time [6], and assessing the temporal and spatial distribution of soil moisture has become one of the major challenges for hydrology and bioclimatology in recent years [7]. The temporal and spatial variability of soil moisture and the relationship between environmental conditions and soil moisture have been widely studied in the past few years [1,4].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
