| 引用本文: | 颜 晓,王德建,张 刚,薄录吉,彭小兰. 长期施磷稻田土壤磷素累积及其潜在环境风险[J]. 中国生态农业学报(中英文), 2013, 21(4): 393-400 |
| YAN Xiao,WANG De-Jian,ZHANG Gang,BO Lu-Ji,PENG Xiao-Lan. Soil phosphorous accumulation in long-term P fertilization paddy field and its environmental effects[J]. Chinese Journal of Eco-Agriculture, 2013, 21(4): 393-400 |
| DOI： | 10.3724/SP.J.1011.2013.00393 |
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| 摘要: 应用常规化学分析法和数学统计方法, 基于太湖地区13年的长期定位试验, 研究长期不同施磷水平下[0(不施磷)、30 kg·hm-2·a-1(低磷)、60 kg·hm-2·a-1(适磷)、90 kg·hm -2·a-1(高磷)]稻麦轮作系统稻田土壤磷素累积规律及磷素流失引发的环境风险。在本试验区土壤环境条件下, 可能发生稻田磷素淋溶及径流的土壤耕层(0~15 cm)Olsen-P临界值分别为26.0 mg·kg-1和24.8 mg·kg-1。连续13年适磷、高磷施肥, 土壤耕层Olsen-P含量分别达到26.9 mg·kg-1和33.2 mg·kg-1, 均高于临界值浓度, 且已导致稻田田面水与30 cm渗漏水中总磷浓度显著升高, 大大提高了稻田磷素淋溶及径流的风险。低磷施肥土壤Olsen-P长期稳定在(10.1±2.0) mg·kg-1水平, 并且每年的稻麦产量与高磷、适磷处理相比并无显著差异, 而长期低磷施肥土壤磷的流失风险也较小。因此, 在太湖地区稻麦轮作体系下, 磷肥不宜以常规适磷水平长期施用, 建议以低磷水平(30 kg·hm-2·a-1)长期施用或以适磷水平(60 kg·hm-2·a-1)间歇式施用。 |
| 关键词: 稻麦轮作系统 施磷 磷素累积 Olsen-P 环境风险 耕层土壤 田面水 渗漏水 |
| 中图分类号: |
| 基金项目:国家自然科学基金项目(40871145)和中国科学院知识创新工程重要方向性项目(KZCX2-YW-440)资助 |
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| Soil phosphorous accumulation in long-term P fertilization paddy field and its environmental effects |
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YAN Xiao1, WANG De-Jian2, ZHANG Gang2, BO Lu-Ji1, PENG Xiao-Lan1
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1.Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
2. University of Chinese Academy of Sciences, Beijing 100049, China;2.Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
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| Abstract: The continuous and excessive application of phosphorus (P) fertilizers and manure in intensive agricultural systems have led to soil P accumulation and progressive saturation of soil sorption capacity. This has significantly influenced soil P loss and P accumulation in aquatic ecosystems. The Taihu Lake Region of the Yangtse River Delta has for decades been a highly intensive agricultural production zone in China. Here, applications of chemical fertilizers and farmyard manure have been an effective method of improving soil fertility and productivity. Long-term applications of fertilizers and/or manure, often in excess of immediate plant uptake, have resulted in significant P accumulation and loss in this region. This has considerably increased the potential for eutrophication in the Taihu Lake. The change-point theory (with a soil Olsen-P content threshold above which the potential for significant P loss from soils to water systems occurred) has been considered to be scientific and useful in P management in agricultural soils. Up to date, however, there has been less report with respect to the Olsen-P change-point theory for paddy soils in the Taihu Lake Region. In this study, a long-term (13 years) P fertilization experiment in four P application doses (0 kg·hm-2·a-1, 30 kg·hm-2·a-1, 60 kg·hm-2·a-1 and 90 kg·hm -2·a-1) was conducted in the Taihu Lake Region to evaluate the accumulation of Olsen-P under rice-wheat rotation cropping system. The experiment evaluated the environmental risks caused by P loss from soils to water systems. Topsoil (0~15 cm), surface water and leachates (30 cm and 60 cm) Olsen-P and total P (TP) contents were determined. Furthermore, a split-line regression model was used to estimate the risks of P loss from soils to water bodies and the change-point of soil Olsen-P in the Taihu Lake Region determined. Although, TP concentrations in surface water bodies and in 30 cm leachate significantly increased with increasing application rate of fertilizer-P, no significant increase was observed in the 60 cm leachate. As the risk of P runoff was mainly in the first 9 days after fertilizer-P application, it was advisable to control paddy field drainage during this period. Split-line regression analysis suggested that the change-points of Olsen-P content in surface soil triggering P leaching and runoff were respectively 26.0 mg·kg-1, 24.8 mg·kg-1. Fertilizer-P application at 60 kg·hm-2·a-1 and 90 kg·hm-2·a-1for 13 years resulted in respective soil Olsen-P accumulation of 26.9 mg·kg-1 and 33.2 mg·kg-1, which were all higher than the change-points. TP concentration of 30 cm leachate was also increased significantly. With continuous application of fertilizer-P at 30 kg·hm-2·a-1 for 13 years, soil Olsen-P content remained at (10.1±2.0) mg·kg-1. This was sufficient for optimum rice/wheat growth without any risk of P loss. It was therefore not suitable to continuously apply 60 kg·hm-2·a-1 of fertilizer-P for a long time in paddy fields. The results demonstrated that intermittent fertilizer-P applications at 30 kg·hm-2·a-1 and 60 kg·hm-2·a-1 were suitable for rice-wheat rotation cropping system in the Taihu Lake Region. |
| Keyword: Rice-wheat rotation system, P fertilization, P accumulation, Olsen-P, Environmental risk, Topsoil, Surface water, Leachate |
