Irrigation management of peanut with a moving sprinkler system: Runoff, yield, and water use efficiency

Irrigation of peanut (Arachis hypogaea L.) with a moving sprinkler irrigation system (MSIS) could affect runoff, evaporation, and crop yield. The objective was to determine the effects of irrigation management on soil water withdrawal, runoff, peanut yield and quality, and irrigation water use efficiency (WUE). Peanut was grown in a commercial field on a loess soil that is sensitive to seal formation and runoff. Irrigations were applied once every 3 or 7 d during the vegetative stage, and each of these treatments was subdivided into three irrigation-frequency treatments of 3, 7, and 10 d during the flowering and pod-filling stages. The total water applied in the various irrigation treatments, based on the soil moisture deficit up to field capacity, ranged from 575 to 648 mm. The lower the irrigation frequency, the smaller was the amount of water applied. During the vegetative stage, irrigation every 3 d led to faster coverage of the soil surface by the peanut canopy and reduced the amount of runoff by 60 mm compared with irrigation every 7 d. Pod yields in the various treatments ranged from 602 to 651 g m^-2, but the differences were statistically insignificant. Decreasing the irrigation frequencies during the vegetative and pod-filling stages increased the WUE. Since peanut yield was insignificantly affected by the irrigation frequency, the enhanced WUE must have been due to reduced water losses during the irrigation season. The water saving through reduced runoff at the high irrigation frequencies may be canceled by higher losses through evaporation from the soil, interception by the canopy, and water removal by wind. One also has to consider the additional labor requirement and nonirrigating movements of the MSIS under high-frequency irrigation management; these are factors that detract from the advantages of the MSIS.