Effects of Organic Manure and Other Nitrogen Substitutes on Spring Maize Growth, Yield, and Water and Fertilizer Utilization Efficiency

Abstract

[Objective] This study was aimed to investigate the effects of organic manure replacing chemical fertilizer with equal nitrogen under different nitrogen application rates on the growth, yield and water-fertilizer use efficiency of spring maize in the dry zone of northern Shaanxi. [Methods] Multiple regression analysis and three-dimensional fitting models were used to establishing an optimal nitrogen management model for spring maize cultivation in northern Shaanxi. In this experiment, three nitrogen application levels (240, 180, 120 kg/hm2 for N1, N2, N3, respectively) and five organic manure replacing chemical fertilizer with equal nitrogen ratios (R0, R12.5, R25, R37.5, R50 for 100% chemical fertilizer nitrogen, 12.5% organic fertilizer nitrogen+87.5% chemical fertilizer nitrogen, 25% organic fertilizer nitrogen+75% chemical fertilizer nitrogen, 37.5% organic fertilizer nitrogen+62.5% chemical fertilizer nitrogen, 50% organic fertilizer nitrogen+50% chemical fertilizer nitrogen, respectively), a total of 15 treatments. During the main reproductive period of spring maize, spring maize growth and yield and yield components were measured, and water consumption (ET), water use efficiency (WUE), nitrogen fertilizer partial productivity (NPFP) and economic benefits were calculated. [Results] The Logistic function had a high fit for dry matter accumulation in spring maize, the R12.5 treatment delayed the start, the end and the appearance of the maximum value of the period of rapid dry matter accumulation, and the N2 treatment enhanced the maximum daily growth rate of dry matter accumulation. Nitrogen application and replacement ratio significantly affected dry matter accumulation, yield and components, ET, NPFP and economic efficiency of spring maize (p<0.05), and the interaction significantly affected ear length, ear coarse, and ET (p<0.05). The average dry matter accumulation, yield, ET, and net income of N2 treatment were higher than those of the N1 and N3 treatment 5.58% and 15.80%, 4.25% and 16.76%, 4.96% and 3.41%, 8.76% and 29.42%, respectively. R12.5%~R37.5% treatment significantly enhanced dry matter accumulation, yield and components, ET, WUE, NPFP, net income and input/output. WUE continued to increase with increasing N application, while NPFP continued to decrease. Treatment N2R25 had the highest dry matter accumulation and ET, and treatment N2R37.5 had the highest yield, net income, and input/output. Spring maize yield was significantly and positively correlated with dry matter accumulation, ET, WUE, net income and input/output. [Conclusion] The comprehensive analysis obtained showed that dry matter accumulation, yield, WUE, NPFP, and net income of spring maize could be optimized simultaneously at the N application and replacement ratio intervals of 190~210 kg/hm2 and 17%~29%, respectively.

Keywords

• spring maize
• yield
• organic fertilizer
• water use efficiency
• multiple regression analysis