| 引用本文: | 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,2022,41(4):1-12. |
| 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,2022,41(4):1-12. |
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| 摘要: |
| 【目的】探明不同水氮耦合模式下氮素吸收利用与迁移转化规律。【方法】在2 a冬小麦和夏玉米大田水氮耦合试验的基础上，分别设置P模式：施肥5 kg下的不同灌水量（P1=10 m3、P2=20 m3、P3=40 m3），N模式：灌水30 m3下的不同施肥（N1=5 kg、N2=10 kg、N3=15 kg），以及各模式下的干（AM1）、中（AM2）和湿（AM3）土壤初始含水率状态，应用Hydrus-1D模拟分析其对氮素吸收利用与迁移转化过程的影响。【结果】①灌后1~4 d，土壤含水率剧烈增加，表层淋失通量大于转化通量，氮循环以淋失的外循环为主。灌水4 d后，上部含水率逐渐稳定，氮循环由外循环淋失为主变为以内循环转化为主。而深层（70~500 cm）因为转化速率小，含水率高，一直以氮淋失的外循环为主。②在P模式下，灌水量和初始含水率增加都会引起作物氮素吸收量的下降；浅层（100 cm）累积NH4+-N和NO3--N淋失、矿化、硝化和反硝化通量均随灌水量增加逐渐增大，转化通量变化范围分别为1~2.5、1~4、0~0.6 mg/cm2；深层转化通量较小且稳定。③在N模式下，作物吸收通量随施肥量的增加而增大；100 cm以上土层的累积水分渗漏量变化小，但无机氮累积渗漏量随施肥量增加而显著增大，100 cm以下的累积水分和无机氮渗漏量变化小；矿化、硝化和反硝化通量在表层随施肥量增加而逐渐增大，变化范围分别为1~2.5、1.5~16、0.3~1.2 mg/cm2，而100 cm以下各通量变化小且稳定。【结论】适宜的水氮耦合模式可提高作物对氮素吸收利用，综合考虑氮素内外循环过程，在AM1-2时525~900 m3/hm2灌水量和225 kg/hm2施肥量为最佳水氮模式。 |
| 关键词: 水氮耦合；氮素吸收利用；氮矿化、硝化和反硝化；Hydrus-1D |
| DOI：10.13522/j.cnki.ggps.2021595 |
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| The Effects of Water-nitrogen Coupling on Uptake and Transformation of Nitrogen in Soil |
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LIU Xiuhua, LU Jie, QI Yan, et al.
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1.School of Water and Environment, Chang’an University, Xi’an 710054, China;
2.Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Xi’an 710054, China
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| Abstract: |
| 【Objective】Nitrogen (N) is the most important plant nutrient but its leaching to surface and subsurface water bodies is a great environmental concern. The dynamics of N in soil is mediated by a multitude of biotic and abiotic processes, and the aim of this project is to investigate the effect of water-nitrogen coupling on it.【Method】A two-year experiment involving winter wheat-summer maize rotation was conducted. It consisted of two sets of treatments. The first one kept N fertilization at 5kg with the irrigation amount varying from 10 m3 to 40 m3; the second one kept the irrigation amount at 30 m3 with N fertilization varying from 5 kg to 15 kg. Added to these are three initial soil water treatments: dry, moderate and wet. Water and nitrogen movement in each treatment was simulated using the Hydrus-1D model.【Result】Soil water content in the proximity of the soil surface increased drastically in the first four days after the irrigation, and spatiotemporal change in N was dominated by its movement more than by its transformation. After that, soil water in the topsoil stabilized asymptotically and the N change was dominated by transformation. N transformation in the subsoil (70~500 cm) was weak. Increasing irrigation amount or reducing initial soil water content led to a decrease in root uptake of N. The accumulated leaching of NH4+-N and NO3--N from the top 100 cm of soil increased with the irrigation amount. Increasing irrigation amount boosted mineralization, nitrification and denitrification, with their associated rates varying in the range of 1~2.5 mg/cm2, 1~4 mg/cm2 and 0~0.6 mg/cm2, respectively. Root N uptake from the top 100 cm of soil increased with N fertilization. The cumulative leaching of NH4+-N and NO3--N remained almost the same under different irrigation amounts, though increasing greatly with N fertilization. Mineralization, nitrification and denitrification in the topsoil increased with fertilization, with their rates varying in the range of 1~2.5 mg/cm2, 1.5~16 mg/cm2 and 0.3~1.2 mg/cm2, respectively. In contrast, their reactions in soil deeper than 100 cm were comparatively slow.【Conclusion】A rational water- nitrogen coupling can improve root N uptake and utilization. When initial soil water content was dry, coupling 525~900 m3/hm2 of irrigation with 225 kg/hm2 of N fertilization was optimal for winter wheat-summer maize rotation in the areas we studied. |
| Key words: water-nitrogen coupling; nitrogen uptake and utilization; nitrogen mineralization, nitrification and denitrification; Hydrus-1D |
