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| DOI：10.13522/j.cnki.ggps.20180197 |
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| Photosynthesis, Water and Nitrogen Use Efficiency of Maize as Impacted by Different Combinations of Water and Nitrogen Applications |
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LIU Ming, ZHANG Zhongxue, ZHENG Ennan, CHEN Peng, CHEN Shuaihong, SHANG Wenbin
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1.School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China; 2.Key Laboratory of High Efficiency Utilization of Agricultural Water Resources, Ministry of Agriculture, Harbin 150030, China
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| Abstract: |
| 【Objective】 This paper aimed to find an optimal combination of water and nitrogen application which can simultaneously improve their use efficiency by maize under sprinkler irrigation. 【Method】The experiment consisted of three irrigation levels : No irrigation (W0); irrigating 40mm (W1) and irrigating 80 mm (W2); and four nitrogen fertilizer applications: No fertilizer (N0), 180 kg/hm2 (N1), 230 kg/hm2 (N2) and 280 kg/hm2 (N3). In each treatment, we measured photosynthetic rate, leaf water use efficiency (WUEi) at jointing stage, above- and below- ground biomass at mature stage, yield, overall water use efficiency (WUE) and nitrogen accumulation and nitrogen fertilizer utilization. 【Result】 With increase in nitrogen fertilizer application, the photosynthetic rate at the jointing stage increased but at a decreasing rate. Nitrogen fertilizer application had a positive effect on WUEi, but was less effective when the irrigation amount was between 40 mm and 80mm. Compared with N0+W0, N2+W1 increased the above-ground biomass and yield by 54.27% and 78.36% respectively. The WUE varied between 2.31 to 3.61 kg/m3, and under the same nitrogen application, the WUE of different irrigations ranked in W0>W1>W2. Irrigation and nitrogen application increased nitrogen accumulation in plants and grains, especially nitrogen application whose impact at the maturity stage was significant (P<0.05). Nitrogen accumulation peaked in W1 differing significantly from that in W0, but was statistically the same as that in W2. The partial productivity of nitrogen decreased with the increase in nitrogen fertilizer application. Under the same nitrogen fertilizer application, the partial production of irrigation was ranked in W1>W2>W0. N2+W1 gave the highest NUW in terms of grain output. Except N3, the grain production efficiency of nitrogen increased with irrigation amount despite at a decreasing rate.【Conclusion】With nitrogen application increasing, both dry biomass and WUE increase but the NUW increases at a decreasing rate. Partial productivity of nitrogen is negatively related to nitrogen application. The experimental results suggest that irrigating 40 mm and applying 230 kg/hm2 of nitrogen is an optimal combination under sprinkler irrigation. |
| Key words: sprinkler irrigation; water and nitrogen coupling; photosynthetic characteristics; yield; dry mass; utilization of water and nitrogen; maize |
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