Effect of Irrigation and Water-Table Depth on Crop Yields
1974
Follett, R. F. | Doering, E. J. | Reichman, G. A. | Benz, L. C.
The objective in this field study was to determine the most desirable combination of amount of irrigation and degree of drainage for production of corn (Zea mays L.), sugarbeets (Beta vulgaris L.), and alfalfa (Medicago sativa L.) grown on sandy soil over a declining water table. Irrigation was applied at weekly intervals at rates of either O, 0.5, 1.0, or 1.5 tunes the water requirement of the crops as predicted by the modified Jensen-Haise equation. Irrigation amounts were applied in combination with shallow, medium, and deep drainage. In 1971 and 1972, early season depth to water table was 92 and 69 cm for the shallow drainage treatment, 166 and 145 cm for the medium, and 186 and 193 cm for the deep. Water-table declines were 94 and 96 cm during the 1971 and 1972 growing seasons, respectively, under all treatments. Corn was harvested at maturity, sugarbeets in mid-October, and alfalfa (three cuttings) at 1/10 bloom. Maximum yields of all crops occurred over the shallow water table; no yield response to irrigation was observed over the shallow water table. Both corn and sugarbeets grown over the medium and deep water tables responded to irrigation as did alfalfa grown over the deep water table. Regardless of irrigation amount, crop yields from deeper water tables never exceeded those from the shallowest water table. Results indicate a need for research on methods for developing practical systems of controlled shallow drainage on a field scale.
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