Spatial and Temporal Distribution of Soil Water Content in Fields under Different Vegetation Conditions Based on TDR Measurements

Abstract

TDR (Time-domain reflectometry) is an advanced method for monitoring the water content in fields. TDR measurements can provide accurate information about vegetation effects on both spatial and temporal soil water distribution. The objective of this study was to examine the effects of vegetation conditions on the distribution of the soil water content. Soil water content was measured to express the spatial distribution in the surface layer (0-0.2 m) in grass, corn, and non-planted fields. Additionally, using the TDR method with multiple probes with different lengths, the measurements were conducted on a temporal basis at 4 depths (0-0.1, 0.1-0.2, 0.2-0.3 and 0.3-0.5 m) to determine the soil-water content profiles in the 3 fields. A significantly higher water content in both the grass and cornfields was found, compared to the non-planted field. Moreover, in the cornfield, we observed that microtopographic features significantly affected the spatial water distribution. The lower the soil water content, the higher the coefficient of variation of the soil moisture content. These results indicated that the effects of the vegetation conditions on the soil water distribution in the fields were significant. From the observation of the temporal soil water profiles in the 3 fields, it was found that soil management, i.e. tillage or no-tillage, was a major factor affecting the profiles.Discipline: Agricultural engineering Additional key words: electromagnetic wave, Andisol, multiple probes with different lengths JARQ 37 (4), 243 -248 (2003)

Spatial explicit soil moisture analysis: pattern and its stability at small catchment scale in the loess hilly region of China

“…Soil moisture varies greatly across space and time (Heathman et al ., ) based on different soil properties (Timm et al ., ), topographic features (Yeh and Eltahir, ; Western et al ., ; Ali et al ., ), vegetation characteristics (Gomez‐Plaza et al ., ; McLaren et al ., ; Miyamoto et al ., ) and atmospheric dynamics (Ramos and Mulligan, ; Teuling et al ., ). Although at a regional scale, soil moisture spatial pattern is dominated by precipitation and radiative forcing (Li et al ., ; Das et al ., ), at field or small catchment scale, the interaction among soil, vegetation and topography (Grayson et al ., ) always has assignable effects on soil moisture variability.…”

The multi-scale spatial variance of soil moisture in the semi-arid Loess Plateau of China

“…features (Western et al 1999;Yeh and Eltahir 1998;Ali et al 2010), vegetation characteristics (Gomez-Plaza et al 2001;McLaren et al 2001;Miyamoto et al 2003) and atmospheric dynamics (Ramos and Mulligan 2005;Teuling et al 2007). From the past research, soil moisture measurements are available only at a very fine scale (at in situ monitoring facilities, e.g., gravimetric sampling or time domain reflectrometry) or at a very coarse scale (by remote sensing retrieval) on a regular basis (Das et al 2010).…”