| 摘要: |
| 【目的】明确再生水灌溉土壤氮素矿化过程及其特征。【方法】采集再生水和清水灌溉年限为5 a的常规施氮设施土壤，风干过2 mm筛备用。采用室内常温培养的方法，分别添加不同质量浓度外源氮肥，分析不同外源施氮量对设施土壤氮素矿化特征的影响；并利用Matlab构建矿化时间、外源施氮量与氮素矿化量的耦合模型。【结果】与清水灌溉土壤相比，再生水灌溉土壤矿质氮量提高了1.85~2.64倍；与再生水对照土壤相比，外源施氮200、160、140、100 mg/kg处理土壤矿质氮量分别提高了3.43、3.34、2.85、2.38倍；土壤氮素矿化速率大致可划分为2个阶段，第1阶段，0~14 d为矿化激发阶段，第2阶段，14 d以后为稳定矿化阶段；构建了土壤氮素矿化量与外源施氮量、矿化时间的二元二次函数模型，该模型决定系数达到0.9以上，运用该模型预测最佳外源施氮量为212.83 mg/kg，土壤氮素矿化量的最大值为233.23 mg/kg，而对应的矿化时间为26.75 d。【结论】外源施氮对再生水灌溉设施土壤氮素矿化具有正激发效应，外源施氮量为160 mg/kg时，土壤氮素净矿化量最大，达到85.89 mg/kg，土壤氮素矿化量与外源施氮量、矿化时间的关系可表达为二元二次函数。 |
| 关键词: 外源施氮； 再生水灌溉； 净矿化量； 矿化速率； 耦合模拟 |
| DOI：10.13522/j.cnki.ggps.20190127 |
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| 基金项目: |
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| Effects of Nitrogen Rates on Nitrogen Mineralization of Greenhouse Soil with Reclaimed Water Irrigation |
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LI Ping, GUO Wei, HAN Yang, LIU Duo, DU Zhenjie, ZHANG Yan, QI Xuebin
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1. Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China; 2. Key Laboratory of High-efficient and Safe Utilization of Agriculture Water Resources of Chinese Academy of Agricultural Sciences, Xinxiang 453002, China; 3. Agriculture Water and Soil Environmental Field Science Research Station of Chinese Academy of Agricultural Sciences, Xinxiang 453002, China
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| Abstract: |
| 【Objective】The research on nitrogen turnover in greenhouse soil is of great significance for reducing chemical nitrogen fertilizer input and maintaining soil quality. However, the process of organic nitrogen mineralization and its characteristics with reclaimed water treatment under nitrogen rates are still unclear. 【Method】This paper collected the soil of conventional nitrogen application with reclaimed water and clean water for 5 years, and air-dried through 2 mm sieve for use. The indoor normal temperature culture method was used to add nitrogen rates, and the effects of nitrogen rates on nitrogen mineralization characteristics of the facility soil were analyzed. The coupling relationship between the days of incubation, nitrogen rates and nitrogen mineralization was constructed by using Matlab. 【Result】The soil mineral nitrogen content treated with reclaimed water increased by 1.85~2.64 times compared with freshwater treated soil. Compared with reclaimed water control soil, nitrogen application was 200, 160, 140, 100 mg/kg, the mineral nitrogen content increased by 3.43, 3.34, 2.85, and 2.38 times, respectively. The soil nitrogen mineralization rate could be roughly divided into two stages, the first stage was priming stage in 0 to 14 day, the second stage was a stable mineralization stage after 14 d. A binary quadratic function model of soil nitrogen mineralization, nitrogen rates and incubation days was constructed. The determination coefficient of the model was above 0.9. The model was used to predict the optimal nitrogen application rate of 212.83 mg/kg, and the maximum value of soil nitrogen mineralization was 233.23 mg/kg, and the corresponding mineralization time was 26.75 d. 【Conclusion】 Therefore, nitrogen application has positive stimulating effect on nitrogen mineralization of the soil irrigation with reclaimed water. When nitrogen application rate was 160 mg/kg, the net mineralization of soil nitrogen was the largest, reaching 85.89 mg/kg. The relationship between mineralization amount, nitrogen application rate and incubation days could be expressed as a binary quadratic function. |
| Key words: nitrogen additions; reclaimed water irrigation; net mineralization; mineralized rate; coupled modeling |
