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| DOI：10.13522/j.cnki.ggps.2019123 |
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| Combined Effects of Water and Nitrogen Application on Growth and Water Use of Summer Maize under Drip Irrigation |
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CAI Xiao, WU Xiangyun, WANG Dong, LIN Xiang, ZHANG Junpeng
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1. College of Water Conservancy and Civil Engineering, Shandong Agricultural University, Taian 271018, China; 2. College of Agriculture, Shandong Agricultural University, Taian 271018, China
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| Abstract: |
| 【Background】Water scarcity and low fertilizer use efficiency are two problems facing agricultural production in China. Reducing water use and improving nitrogen use efficiency have been mandated by Chinese government in its effort to develop sustainable agriculture.【Objective】The purpose of this paper is to study experimentally the combined effects of water and nitrogen application on root water uptake and growth of summer maize under drip irrigation.【Method】A two-year field experiment was conducted in 2018—2019 under different combinations of irrigation amounts and nitrogen applications. Three were four N treatments: 120 kg/hm2 (N120, in 2019 only), 180 kg/hm2 (N180), 240 kg/hm2 (N240) and 300 kg/hm2 (N300). The difference in irrigation treatments was the criterion used to determine the irrigation amount. Plots in all treatments were irrigated at planting, jointing and tasseling stage, with the amount to water in each irrigation calculated as the water required to top up the soil water in 0~10 cm (W10, in 2019 only), 0~20 cm (W20), 0~30 cm (W30) and 0~40 cm (W40) soil layer to the field capacity, respectively. In each treatment, we measured the leaf area index (LAI), aboveground biomass, yield components, evapotranspiration and water use efficiency (WUE). 【Result】The aboveground biomass and LAI both increased with water and N application, but there was no significant difference between N240 and N300. The effect of N application on seed yield was more significant than the combined impact of water and N. In 2018, only was the yield of W20N180 lower than that of W40N300, while in 2019 the yield of all treatments, except W10 coupled with all N treatments and N120 coupled with all irrigation treatments, was comparable to the yield of W40N300. The evapotranspiration increased with water and nitrogen application, and WUE varied with irrigation. Compared to W40, the average WUE in W20 and W30 increased by 11.05% and 1.74% respectively in 2018, and by 9.11% and 7.21% respectively in 2019. 【Conclusion】To best balance irrigation amount, N application, grain yield and WUE, the optimal irrigation and fertilization for the summer maize under drip irrigation in this area is: Irrigating and fertilizing at sowing, jointing and tasseling stage by topping up the water content in 0~20 cm soil layer to the field capacity, with 180 to 240 kg/hm2 of N applied with the irrigations at 1∶1∶1 ratio at the three stages. N in the sowing sage was broadcasted as basal fertilizer. |
| Key words: summer maize; supplementary irrigation with drip irrigation; water-nitrogen interaction; maize yield; water use efficiency |
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