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| DOI：10.13522/j.cnki.ggps.20190127 |
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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 |
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