Abstract:Judgement of crop water requirement just by soil water content is not competent, which is closely related with crop yields and water use efficiency. Corn water consumption and yield in response to mulching method (M1: fully mulched and M2: partially mulched), and irrigation amounts (I1 and I2) under variable drip irrigation lateral spacings (A1: 1m and A2: 0.5m) were investigated over two growing seasons in the Hetao Irrigation District under arid growing conditions. Results showed that evapotranspiration (ET) in partially mulched treatments were higher than that in treatments with full mulch cover under low irrigation frequency. However, the yields and water use efficiency (WUE) were lower under partial mulched treatments compared with full mulch. Closer lateral spacing had no effect on ET under low irrigation frequency, but yield was increased with high irrigation amount under low irrigation frequency. The yield response factor (ky) of the crop water production function(CWPF) was sensitive to mulching method and it was lower in partially mulched treatments than in fully mulched treatments under low irrigation frequency. Under high irrigation frequency, ky was sensitive to irrigation amounts, mulching methods and lateral spacing. The CWPF along with WUE and crop yield can aid in the selection of optimal irrigation and mulching management. Considering ky, yield, WUE and costs, partial mulch with 1m lateral spacing under high irrigation amount and full mulch with 0.5m lateral spacing with low irrigation amount was optimal under high irrigation frequency while either 1m or 0.5m lateral spacing under partial mulch with low irrigation amount was optimal under low irrigation frequency, respectively. This study can guide irrigation application for maize in the Hetao Irrigation District.
