Water Use Characteristics of Wide-Spaced Furrow Irrigation

Abstract

Water extraction, depletion, and sufficiency of wide-spaced furrow irrigation (WSFI) are not well understood. In addition, there is little work showing the response of WSFI where the same seasonal amount of water was applied to both WSFI and every-furrow irrigation (EFI). Treatments in this study included two seasonal amounts of water applied to both the WSFI and EFI plots. We determined the yield of grain sorghum [Sorghum bicolor (L.) Moench], water uptake (surface evaporation, extraction, and seasonal depletion), water penetration depth, and water use efficiency (WUE) during a 2-yr study in the Oklahoma Panhandle. A given amount of water produced about a 10% higher yield of grain sorghum when applied as WSFI than as EFI. The WUE of plants was found to be 24% higher for WSFI than for EFI. Evaporation from the soil surface was 30 mm greater for EFI than WSFI. The EFI resulted in 30 mm more water extraction from the soil, evidently to meet the demand of surface evaporation. Seasonal depletion was related to wetness of the treatment; depletion was 20 mm higher for the drier of the two treatments. Following any periods where water was not available, WSFI showed less water penetration depth than EFI. The WSFI appears to have benefit for irrigation of this crop.