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| DOI：10.13522/j.cnki.ggps.2017.0002 |
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| Regulating Fertilizer Application to Control Nitrogen Migration under Subsurface Drip Irrigation |
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ZHENG Wensheng, MENG Yan, LI Fanghua , WANG Bai, LIU Xiao
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1. Heilongjiang Provincial Hydraulic Research Institute, Harbin 150080, China; 2. Heilongjiang Provincial Key Laboratory of Agricultural Water-saving Engineering in Cold Region, Harbin 150080, China
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| Abstract: |
| 【Objective】 The movement and transformation of nitrogen in soil impacts nitrogen bioavailability, and the purpose of this paper is to investigate the feasibility of regulating fertilizer application to control nitrogen migration in soil. 【Method】 Field experiments were conducted with three levels of nitrogen application: 60, 120 and 180 kg/hm2, with each applied either just once or in three times to a corn field via subsurface irrigation. During the experiments, spatial distribution of NH+4 and NO-3 in soil, as well as N accumulation in the plants were measured. Overall, we examined six N fertilizer treatments: applying 60 kg/hm2 once (T1N60), applying 120 kg/hm2 once (T1N120), applying 180 kg/hm2 once (T1N180), applying 60 kg/hm2 in three times (T3N60), applying 120 kg/hm2 in three times (T3N120), and applying 180 kg/hm2 in three times (T3N180). 【Result】 ①Applying the fertilizer at the jointing stage just once increased nitrate and ammonium content in 0~60 cm compared with applying it in three times. In particular, the ammonium and nitrate under T1N60 increased by 16.46% and 14.75% compared T3N60, increased by 23.23% and 7.48% under T1N120 compared to T1N120, and increased 10.62% and 10.05% under T1N180 compared to T3N180. In contrast, applying the fertilizer in three times at the filling stage increased both ammonium and nitrate in 0~60 cm soil compared to applying the same amount of fertilizer just once. ②In the late growth stage, the amount of residual nitrate in 20~40 cm in all treatments was higher when applying the fertilizer in three times than applying it just once, maximizing in T3N180. ③Nitrogen uptake by plant roots increased by 3.7% on average when the fertilizer was applied in three times compared to applying it just once, especially in T3N180 and T3N120. 【Conclusion】 For a given amount of fertilizer, applying it via several top-addressing can enhance root uptake and reduce leaching and emission in comparison with applying it just once. We suggest applying 120 kg/hm2 of fertilizer via three top-addresses. |
| Key words: Subsurface irrigation; nitrogen management; ammonium nitrogen; nitrate nitrogen; nitrogen migration |
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