Evapotranspiration, Yield, and Water Use Efficiency of Corn Hybrids Differing in Maturity

摘要: Short-season corn (Zea mays L.) hybrids may reduce irrigation requirements and permit earlier harvest. We measured compared evapotranspiration (ET) of a short-season (SS, Pioneer 3737) full-season (FS, 3245) hybrid under full in 1994 at Bushland, TX, examined differences growth, yield, water use efficiency (WUE). Both were planted the same day contiguous 4-ha fields (each field with weighing lysimeter to measure ET directly), irrigated simultaneously until SS reached mid grain fill (R5 dent stage), managed for high productivity. Harvest was normal field-dried content 136 g kg -1 region. Rainfall 320 mm; 465 577 mm applied FS fields, respectively. Seasonal reduced 673 FS, 802 mm), primary reduction after anthesis. Peak daily rates (some >10 d ) not affected by type. Grain yields (dry basis) declined from 1322 1130 m -2 , but (WUEg = yield/ET) similar across hybrids: SS, 1.68 -3 ; 1.65 . Dry matter (DM) >390 hybrid, DM (WUEd DM/ET) identical two hybrids, 3.02 The physiological maturity 12 than harvested 11 sooner. Leaf area index >5.5 2 barely >4 hybrid. WUE peak appreciably different when fully irrigated, although seasonal less A shorter-maturity can requirement, it will needed capacity (flow per unit area) more 5 10%, as that is largely dictated near-maximum rate avoid soil deficits corresponding yield reduction. With prevailing regional pumping production costs, income would be six eight times saving cost, this could offset higher marketing prices an harvest opportunity grazing winter wheat (Triticum aestivum double-crop.