Limited Irrigation of Corn–Based No–Till Crop Rotations in West Central Great Plains.

Identifying the most profitable crop rotation for an area is a continuous research challenge. The objective of this study was to evaluate 2-, 3-, and 4-yr limited irrigation corn (Zea mays L.)-based crop rotations for grain yield, available soil water, crop water productivity, and profitability in comparison with 1 yr continuous corn (CC). A field study was conducted from 2001 through 2010 on a deep silt loam soil near Tribune, KS. The study consisted of four crop rotations, that is, CC, corn–winter wheat (Triticum aestivum L.) (C–W), corn–winter wheat–grain sorghum (Sorghum bicolor L.) (C–W–Gs), and corn–winter wheat–grain–sorghum–soybean [Glycine max (L.) Merr.] (C–W–Gs–Sb) with irrigation limited to 254 mm annually. Grain yield of corn from the CC rotation was significantly lower, on average by 2.5 Mg ha^-1, than corn yield from the other three rotations mainly due to difference in irrigation level. However, the mean yield of CC over one cycle of rotation [∼10.2 Mg (ha rotation-cycle)^-1] was significantly greater than mean corn equivalent grain yield of the other three rotations over one cycle of each rotation. Seasonal soil water usage from upper depths of the soil profile was significantly greater for CC. In this study, average crop water productivity [16.6 kg (mm ha)^-1] and profitability of the CC rotation were also greater than in the other rotations. In selecting profitable rotations, producers should consider crop yield potential and value in addition to resilience. [ABSTRACT FROM AUTHOR]