ALTERNATE-FURROW IRRIGATION FOR SOYBEAN PRODUCTION

Alternate-furrow irrigation reduces water application without affecting yield and thereby leads to more efficient water use. A 2 year (1988-1989) field study was conducted to compare alternate-furrow irrigation to conventional every-furrow irrigation with soybeans [Glycine max (L. ) Merr.] at the South Central Research and Extension Center near Clay Center, Nebraska on a Hastings silt loam soil (fine, montmorillonitic, mesic Udic Argiustol). Conventional 0.76-m irrigation (every furrow) and wide 1.52-m irrigation (alternate furrow) were compared in relation to soybean yield, water use efficiency, soil water change, and water advance down the furrow. The soybean cultivar Resnik (indeterminate, group III) in a twinrow planting system was used. The two furrow irrigation treatments were evaluated in a randomized complete block with six blocks in each year. Yields were similar in the two furrow irrigation treatments although less water (46% less gross and 29% less net) was applied to the alternate than to the every-furrow irrigation treatment. Total water use efficiency (TWUE) was 6.12 and 5.52 kg.ha-1.mm-1 for the alternate and every-furrow irrigation, respectively. Net irrigation water use efficiency (NIWUE) for the alternate and every-furrow treatments were 57 and 36 kg.ha-1.mm-1, respectively, across the 2 years. Runoff was less in the alternate-furrow irrigation treatment. There was no effect of furrow irrigation spacing on soil water change in the 1.52 m soil profile during the irrigation season. Alternate-furrow irrigation produced the same yield as every-furrow irrigation with less water input leading to water conservation.