Soil moisture response to rainfall in forestland and vegetable plot in Taihu Lake Basin, China

Abstract

Soil moisture and its spatial pattern are important for understanding various hydrological, pedological, ecological and agricultural processes. In this study, data of rainfall and soil moisture contents at different depths (10 cm, 20 cm, 40 cm and 60 cm) in forestland and vegetable plot in the Taihu Lake Basin, China were monitored and analyzed for characteristics of soil moisture variation and its response to several typical rainfall events. The following results were observed. First, great temporal variation of soil moisture was observed in the surface layer than in deeper layer in vegetable plot. In contrast, in forestland, soil moisture had similar variation pattern at different depths. Second, initial soil moisture was an important factor influencing the vertical movement of soil water during rainfall events. In vegetable plot, simultaneous response of soil moisture to rainfall was observed at 10-and 20-cm depths due to fast infiltration when initial soil was relatively dry. However, traditional downward response order occurred when initial soil was relatively wet. Third, critical soil horizon interface was an active zone of soil water accumulation and lateral movement. A less permeable W-B soil horizon interface (40-cm depth) in vegetable plot can create perched water table above it and elevate the soil water content at the corresponding depth. Fourth, the land cover was an effective control factor of soil moisture during small and moderate rainfall events. In the forestland, moderate and small rainfall events had tiny influences on soil moisture due to canopy and surface O horizon interception. Fifth, preferential flow and lateral subsurface interflow were important paths of soil water movement. During large and long duration rainfall events, lateral subsurface flow and preferential flow through surface crack or soil pipe occurred, which recharged the deep soil. However, in more concentrated large storm, surface crack or soil pipe connected by soil macropores was the main contributor to the occurrence of preferential flow. Findings of this study provide a theoretical foundation for sustainable water and fertilizer management and land use planning in the Taihu Lake Basin.

Performance of GPM-IMERG precipitation products under diverse topographical features and multiple-intensity rainfall in an arid region

“…It evaluates the detectability of events that had fallen over the entire study area, and throughout the entire study period categorized only by precipitation intensity. The approach required imposing various thresholds to classify 255 precipitation intensities thresholds were adopted from Chinese Meteorological department (Zheng et al, 2014) (Table 2).…”

Stratification response of soil water content during rainfall events under different rainfall patterns

“…In previous studies (He et al, ; Liu et al, ; Y. Zhang et al, ), the SWC generally increased during rainfall due to rainfall recharge, and the depth at which the SWC decreased varied among different rainfall patterns. Generally, SWC at 10‐cm depth in all stands responded to rainfall events first; then, there was a lag effect in SWC responses following a rainfall event, especially in deep layers (Q. Li, Zhu, Zheng, Liao, & Yang, ). In this study, the vertical change in SWC during rainfall differed significantly among the different rainfall patterns (Figure ).…”

“…This change in SWC was due to matrix flow (Tao et al, ). However, under the delayed rainfall pattern, SWC increased earlier in the lower soil layers than in the upper soil layers, which was indicative of PF (Q. Li et al, ; Tao et al, ). Thus, the occurrence of matrix flow or PF depended on the rainfall pattern.…”

Effects of Long-Term Vegetation Restoration on Distribution of Deep Soil Moisture in Semi-arid Northwest of China

“…This means that for about half of sampling lands, the effect of soil texture on soil moisture was not significant. The distribution of soil moisture is a result of interactions among many variables, such as vegetation (e.g., vegetable type, coverage, and age), climate (e.g., precipitation, evaporation, and solar radiation), topography (e.g., elevation, slope, and aspect), and soil properties (e.g., soil texture, soil bulk density, and soil hydraulic conductivity) (Yu et al 2018;Li et al 2015;Wang et al 2012b). The variation of these variables makes the distribution of soil moisture highly variable in space and time (Zhang and Shao 2013).…”

“…In recent years, the studies of soil moisture mainly focused on shallow soils (less than 100 cm) (Zhou et al 2015;Gao et al 2011;Gaines et al 2016), and most of the studies considered the influence of vegetation type (Zheng et al 2015;Gómez et al 2000;Jia and Shao 2014), restoration period (Skubel et al 2015;Wafa et al 2018;Song et al 2018), root biomass (Pan et al 2015;Xiao and Huang 2016), precipitation (Li et al 2015;Yang et al 2018;Liu et al 2016), or other single factors on soil moisture, but limited reports were related to the factors affecting the moisture of deep soil layers. For more than 50 years, plants have been used to restore the semiarid northwest of China, and the land coverage, ecological environment, and soil quality are becoming better and better.…”