Objectives To clarify the appropriate combination of water and fertilizer required for optimal maize yield, we studied the effect of water and fertilizer coupling on maize yield under shallow drip irrigation in semi-arid area of western Liaoning Province.
Methods The field experiment was carried out in the semi-arid area (sandy loam) in the west of Liaoning Province. Four factors irrigation (W), nitrogen (N), phosphorus (P) and zinc (Zn) were selected as independent variables, while yield (Y) was considered the dependent variable. Four factors and five levels quadratic regression orthogonal design (1/2 implementation) was used. Irrigation and N fertilizer application were divided into four times, P fertilizer was applied at sowing, and Zn was applied at elongation stage. According to the statistical method of quadratic regression orthogonal experiment design (1/2 implementation), the yield regression model was established. Frequency analysis method was used to analyze the effect of W, N, P, Zn and their interaction on yield (Y).
Results Within the tested five levels of W, N, P and Zn, maize yield increased first and then decreased, showing a parabolic trend. Yield response to single factor was in order of W > N > Zn > P; maize yield response to two-factor interaction was in order of N × P > W × P > P × Zn > W ×N > N× Zn > W × Zn; and a certain interaction of three factors existed to some extent.
Conclusions In the semi-arid area of western Liaoning, the contribution of water, N, P and Zn to spring maize yield was in order of W > N > Zn > P, and the contribution of two-factor interaction was in order of N × P > W × P > P × Zn > W × N > N × Zn > W × Zn. According to the results of frequency analysis, the confidence interval of maize yield reaching 10000–12017 kg/hm2 was 95% under irrigation amount of 46–49 mm, N application rate of 172–209 kg/hm2, P application rate of 84–114 kg/hm2, and Zn rate of 10–13 kg/hm2.
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