Abstract:A 2-year experiment was conducted to investigate the effects of different lateral spacing and mulching methods on soil moisture, soil NO3- concentration, soil water spatial distribution uniformity (CUw), soil NO3- spatial distribution uniformity (CUN), shoot-root growth, grain yield, and harvest index (HI) of spring maize in Hetao Irrigation District. The experiment included two lateral spacing (A1: 1 m; A2: 0.5 m) and two mulching methods (M1: fully mulched; M2: partially mulched). Results showed that soil moisture was consistent with CUw in root zone, however, the increased soil NO3- concentration did not lead to an increased CUN under high-frequency mulched drip fertilization. The improvement of soil water (and CUw) and NO3- (and CUN) did not significantly influence crop root length (or weight) density, but it increased leaf area, and finally reduced root-shoot ratio. Compared with laterals layout, mulching methods imposed more effects on crop yield and HI. Under low-frequency irrigation condition, compared with partial mulching, full mulching increased soil moisture and NO3- concentration in root zone and resulted in higher crop yields and HI; however, grain yields and HI in full mulching were lower than that in partial mulching under high frequency irrigation condition. In this study, grain yields and HI were the highest when the ratio of root surface area and leaf area (RSA/LA) was equal to 4, the too high or too low RSA/LA reduced crop yield and HI. Based on high grain yield, HI, and low costs of drip taps, A1M2 was recommended under high fertigation frequency, while A1M1 was recommended under low fertigation frequency.