Water Loss from an Irrigated Sorghum Field: I. Water Flux within and below the Root Zone
1973
Stone, L. R. | Horton, M. L. | Olson, T. C.
Knowledge of actual water movement within field soil profiles under cropped conditions is important in aiding our understanding of water supply to plants and movement of water soluble fertilizers and pesticides. This work was done to evaluate water movement within and below the root zone of a sorghum (Sorghum bicolor (L.) Moench) crop during a 31-day field study following water application. Hydraulic potential data from tensiometers placed at eight depths in the soil profile were used to determine the hydraulic gradients. Soil water flux in various depth layers was calculated using the hydraulic potential gradients and the determined hydraulic conductivity vs soil water content relationships. Upward water movement commenced in the 15 to 30 cm layer 3 days foflowing water application and 130 to 150 cm layer after 19 days. The upward water flux into the root zone reached a maximum of approximately 0.2 cm/day near the end of the study period. During the 31-day study period, 6.0 cm of water were lost from the 150 cm soil profile by flux below the root zone. This illustrates the importance of considering water loss due to flux below the root zone in crop situations.
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