Supported by the National Natural Science Foundation of China (No. 41671304), and the National Key Research and Development Program of China (No. 2017YFD0200206)
水体磷污染及其产生的富营养化等生态效应已成为流域性突出问题，其主要来源之一为农田磷流失。磷流失主要受土壤磷形态及有效性等因素影响，而土壤磷库又具有很强的空间分异特征。因此，聚焦水体富营养化较为突出的太湖流域，选取典型水旱轮作农田土壤为研究对象，基于系统随机布点法采集农田土壤样本319份，植株样本83株，分析土壤磷库演变规律并预测其环境风险。研究结果表明：与全国第二次土壤普查及2009年前期调查结果相比，该区域土壤全磷与有效磷（Olsen-P）含量均显著提高。根据水稻土Olsen-P的临界意义，该区域93.1%的农田土壤有效磷含量超过10 mg·kg–1，土壤基本不缺磷；有效磷高于20 mg·kg–1占总土壤样本的65.2%，说明大部分农田土壤磷库处于盈余状态。进一步基于磷素生物有效性的分级方法（biologically based P，BBP）对土壤磷的生物有效性进行分析，发现氯化钙磷（CaCl2-P）、柠檬酸磷（Citrate-P）、酶提取磷（Enzyme-P）以及盐酸磷（HCl-P）与Olsen-P均呈极显著正相关（P < 0.001），说明四种形态磷素均为土壤有效磷源。土壤全磷和有效磷含量呈极显著正相关关系（P < 0.001），土壤有效磷与植株地上部分（籽粒+秸秆）以及地下部分（根）全磷含量呈显著正相关关系（P < 0.01）。同时基于CaCl2-P与Olsen-P的相关性分析，认为该区域能造成环境风险的土壤有效磷阈值为30 mg·kg–1，超过环境阈值，环境污染风险会大大增加。因此，针对该区域土壤磷库较强的空间差异性，建议在区域养分管理以及环境保护过程中重点关注土壤磷的高效利用。
Objective Agricultural sustainable development and aquatic ecological environment security are faced with numerous challenges. As a non-renewable resource, phosphorus (P) is an essential element for crop growth, but has the potential to cause water eutrophication. Disparities in P management such as fertilizer or manure and the harvested crop P removal result in a massive variation of P imbalances in agricultural systems. Phosphorus loss is mainly affected by the form and availability of soil P.Method Therefore, in this paper, considering strong spatial differentiation characteristics of soil P pools and availability, the soils of typical flood and drought rotation farmlands were selected. The farmlands were located in the Taihu Lake Region in the lower reaches of the Yangtze River. In detail, 319 farmland soil samples and 83 wheat samples were collected based on the systematic random point distribution method. The spatial differences of soil phosphorus fractionations and crop P uptake were analyzed.Result Compared with the results of the second national soil survey and the survey in 2009, soil total P (TP) and available P(Olsen-P)increased significantly in the Taihu Lake Region. Soil Olsen-P concentration in Changshu and Yixing city ranged between 2.19-112.5 mg·kg–1 and 5.21-109.7 mg·kg–1, respectively. The average concentration was 37.6 mg·kg–1 and 29.8 mg·kg–1, which increased by 24.6 mg·kg–1 and 7.9 mg·kg–1 --in contrast to 2009. The concentration of available P exceeded 10 mg·kg–1 of 93.1% of soil samples, and 65.2% of the total soil samples had more than 20 mg·kg–1, which indicated that most of the paddy soil P pool was in surplus. Furthermore, we analyzed soil P availability using the biologically-based P (BBP) method, and found that CaCl2-P, Citrate-P, Enzyme -P and HCl-P had a significant positive correlation with Olsen-P (P < 0.001). This indicates that those four P forms were all available sources of soil P. We also found a notable relationship between soil TP and Olsen-P (P < 0.001) or crop TP (P < 0.01) concentration. Meanwhile, the correlation analysis of CaCl2-P and Olsen-P indicated the breakpoint of environmental risk, which was 30 mg·kg–1.Conclusion In view of the strong spatial differences of soil phosphorus pools in this region, it is suggested to focus on the efficient utilization of soil phosphorus in the regional nutrient management and environmental protection. The results are expected to provide basic data support for increasing P use efficiency as well as agricultural non-point source pollution control in the Taihu Lake Region.
汪玉,袁佳慧,陈浩,陈光蕾,赵洪猛,徐灵颖,赵旭,王慎强.太湖流域典型农田土壤磷库演变特征及环境风险预测[J].土壤学报,2022,59(6):1640-1649. DOI:10.11766/trxb202012160696 WANG Yu, YUAN Jiahui, CHEN Hao, CHEN Guanglei, ZHAO Hongmeng, XU Lingying, ZHAO Xu, WANG Shenqiang. Soil Phosphorus Pool Evolution and Environmental Risk Prediction of Paddy Soil in the Taihu Lake Region[J]. Acta Pedologica Sinica,2022,59(6):1640-1649.复制