| Cite this article: | 刘秀花,卢杰,齐燕,等.水氮耦合对作物氮素吸收利用与迁移转化的影响[J].灌溉排水学报,0,():-. |
| Liu Xiuhua,Lu Jie,Qi Yan,et al.水氮耦合对作物氮素吸收利用与迁移转化的影响[J].灌溉排水学报,0,():-. |
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| Effects of Water-nitrogen Coupling Patterns on Crops Uptake and Nitrogen Transformation and Leaching |
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Liu Xiuhua, Lu Jie, Qi Yan, He Yi, Gao Wande, Chen Yunfei, Hu Anyan, He Junqi
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School of Water and Environment, Chang’an University, Xi’an. Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Chang’an University
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| Abstract: |
| 【Objective】In order to explore the nitrogen utilization, migration and transformation under different water-nitrogen coupling levels. 【Method】Basis on 2-year coupling experiment of water-nitrogen in wheat and maize growing, irrigation water levels P (P1=10 m3, P2=20 m3, P3=40 m3) under 5kg fertilization and fertilization levels N (N1=5 kg, N2=10 kg, N3=15 kg) under 30 m3 irrigation water were used, and consider three initial soil water content states dry (AM1), medium (AM2) and wet (AM3) were set. Hydrus-1d system was used to simulate and analyze the levels effects on nitrogen uptake, transformation and leaching. 【Result】The results showed that (1) in the surface layer, the soil moisture content increased sharply from 1 to 4 days after irrigation, and the leaching flux was greater than the transformation flux. The nitrogen cycle was dominated by the external leaching cycle. After 4 days, the water content in the upper layer gradually stabilized, and the nitrogen cycle changed from the external leaching loss to the internal transformation. In the deep layer (70~500 cm), due to the low conversion rate and high-water content, the nitrogen was always leaching. (2) At P levels, the increasing irrigation amount and dry to wet initial soil water content would lead to the decrease of crop uptakes; in top layer (100 cm), the accumulated leaching fluxes of NH4+-N and NO3--N gradually increased with irrigation amount. The fluxes of mineralization, nitrification and denitrification also increased gradually with the increase of irrigation amount, which ranged of 1-2.5 mg/cm2, 1-4 mg/cm2 and 0-0.6 mg/cm2, respectively. In deep lay, the transformation fluxes were small and stable. (3) At N levels, above 100 cm, crop uptake fluxes increased with the higher fertilizer application. The cumulative leaching flux of NH4+-N and NO3--N had little changed, but they increased greatly with the increasing fertilizer amount, and remained unchanged below 100 cm. However, the fluxes of mineralization, nitrification and denitrification increased gradually with the fertilization amount in the top layer, which range of 1-2.5 mg/cm2, 1.5-16 mg/cm2 and 0.3-1.2 mg/cm2, respectively. While the fluxes had small and stable changed below 100 cm. 【Conclusion】Appropriate water- nitrogen coupling mode can improve crops nitrogen uptake and utilization. At AM1-2 condition, comprehensive consideration of 525~900m3/hm2 irrigation amount and 225kg/hm2 fertilizer application treatment is the best water-nitrogen mode. |
| Key words: irrigation district; water-nitrogen coupling; nitrogen uptake and utilization; nitrogen mineralization, nitrification and denitrification; Hydrus-1D |
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