Tillage effects on the spatial and temporal variations of soil water
Zhai, R. | Kachanoski, R.G. | Voroney, R.P.
The objective of this study was to examine the effect of tillage on the spatial and temporal variability of soil water content of the surface layer (0-0.2 m) under a corn (Zea mays L.) crop. Soil water content was measured nondestructively every 1 to 2 d in fall moldboard (CT). 1-yr no-tillage (SNT), and longer term (>15 yr) no-tillage (LNT) plots using permanently placed time domain reflectometry (TDR) transmission line probes. The plots are located near Guelph, ON, Canada on a Typic Hapludalf (loam) soil. Sampling sites were in the corn row, directly between corn rows (interrow), and halfway between the row and interrow (quarter row). Systematic spatial differences in soil water content, within and between tillage treatments, were observed throughout the entire growing season. Large differences between CT and both LNT and SNT early in the season were attributed to increased evaporation in CT caused by spring secondary tillage. The drying rate in the LNT interrow position was much lower than the CT and SNT interrow drying rates. Soil water recharge from rainfall was distributed systematically in space because of canopy interception and subsequent stemflow. Crop residue on the soil surface of the no-till treatments intercepted a significant amount of rainfall and reduced soil water recharge by 14 and 35% in the SNT and LNT treatments, respectively. The tillage treatments affected the temporal dependence of the spatial variability of soil water and the spatial dependence of the temporal variability.
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