| 引用本文: | 杨继伟,汤广民,李如忠,等.受淹农田土壤-上覆水氮磷迁移特征模拟研究[J].灌溉排水学报,2018,37(12):71-77. |
| YANG Jiwei,TANG Guangmin,LI Ruzhong,et al.受淹农田土壤-上覆水氮磷迁移特征模拟研究[J].灌溉排水学报,2018,37(12):71-77. |
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| 摘要: |
| 【目的】研究受涝农田土壤中氮磷流失规律及上覆排水中氮磷释放特征，探求合理的排水时间。【方法】基于原状土试验测坑开展大豆淹水试验，分析了淹水前后土壤中氮磷变化量、淹水过程中土壤pH值、Eh值以及上覆水中氮磷质量浓度的变化。【结果】随着淹水历时延长，土壤氮磷损失率增加，2次试验淹水结束较淹水前土壤全氮、全磷损失率均值约为7.63%和3.17%，碱解氮降低17.84%，有效磷增加8.65%；上覆水中TN、NH4+-N和NO3--N质量浓度在淹水第1天增速较快，分别达到0.405、0.192和0.209 mg/L，2～4 d时间内TN质量浓度缓慢增加，NH4+-N和NO3--N质量浓度之和减少为0.226 mg/L，第4天至淹水结束，TN和NH4+-N质量浓度增加，NO3--N质量浓度继续降低，整个淹水过程无机氮质量浓度占总氮比例由98.5%降至54.4%；淹水过程中上覆水含磷量不断增加，呈现二次多项式变化特征，淹水结束TP质量浓度为0.615 mg/L，其中可溶性磷酸盐占TP质量浓度的80.5%～91.6%；淹水后，受试土壤的pH值和Eh值降低，进一步增强了土壤中氮磷向上覆水迁移的能力。【结论】综合考虑受淹农田氮磷迁移特征和作物产量等因素，农作物在受淹后应采取控制排水措施，以减少氮磷随地面排水的流失。大豆花荚期受淹后第3天为最佳排水时机。 |
| 关键词: 受淹试验； 农田土壤； 氮磷流失； 控制排水 |
| DOI：10.13522/j.cnki.ggps.20180217 |
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| Loss of Nitrogen and Phosphorus From Soil and Surface Water in Flooded Cropland |
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YANG Jiwei, TANG Guangmin, LI Ruzhong, YUAN Xianjiang, YUAN Hongwei, JIANG Shangming
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1.Water Resources Research Institute of Anhui Province and Huaihe River Commission, Ministry of Water Resources, Bengbu 233000, China; 2. Key Laboratory of Water Conservancy and Water Resources of Anhui Province, Bengbu 233000, China; 3. Department of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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| Abstract: |
| 【Objective】 This paper studies the loss of nitrogen and phosphorus from soil and surface water in flooded cropland in attempts provide data to help design drainage strategies. 【Method】 The experiment was conducted in a lysimeter filled with undisturbed soil and grown with soybean. During the experiment, nitrogen, phosphorus, pH and Eh in the soil as well as nitrogen and phosphorus in the overlying surface water were measured. 【Result】 The loss of N and P from the soil increased with the duration of surface ponding; compared with their values prior to flooding, the average TN and TP loss from the soil was approximately 7.63% and 3.17% at ease of the flooding respectively, in which alkali-hydrolyzable nitrogen reduced by 17.84% while Olsen-P increased by 8.65%. Following the flooding, the concentration of TN, NH4+-N and NO3--N in the surface water increased fast, reaching 0.405, 0.192 and 0.209 mg/L respectively one day after the flooding. Two to four days after the flooding, TN concentration still increased with time but at a decreasing rate with the concentration of NH4+-N and NO3--N reduced to 0.226 mg/L. Four days after the flooding eased, both TN and NH4+-N increased while NO3--N decreased. The ratio of inorganic nitrogen to TN decreased from 98.5% to 54.4% during the flooding duration, while the phosphorus content increased monotonically. The TP content was 0.615 mg/L at the end of flooding with SRP accounting for 80.5%~91.6%. Both pH and Eh dropped following the flooding, thereby enhancing migration of nitrogen and phosphorus from the soil to the overlying surface water. 【Conclusion】 Considering N and P loss from soil and crop yield, timely drainage is essential to reduce nutrient loss without scarifying yield. For the case studied in this work, instigating drainage three days after the flooding appears to be the best compromise. |
| Key words: flooding test; farmland soil; nitrogen and phosphorus loss; controlled drainage |
