摘要
【目的】研究农业面源氮磷污染时空分布特征及植被覆盖度与农业面源输出负荷的驱动关系,探明植被覆盖度与农业面源输出负荷的影响。【方法】以粤西地区的鉴江流域为研究对象,基于SWAT软件构建2000—2020年面源污染模型,分析泥沙、氮磷时空分布特征与潜在空间来源。采用RDA方法分析流域总氮和总磷输出的驱动因素,包括自然因子(降水和植被覆盖)、社会经济因子(人口、三大产业、农林牧渔产值)及农业因子(种/林/牧/渔业、化肥及农药使用量),并结合植被覆盖度定量分析植被覆盖度与农业面源输出负荷的相关性。【结果】①模型能较好模拟鉴江流域径流、泥沙及氮磷过程(R2/NSE>0.5);②2000—2020年流域年均产水量653 mm,产沙量12321.4 t,总氮和总磷通量分别为19629.4 t和5099.3万t;③不同土地利用对氮磷面源污染源贡献:负荷量林地(占70%,其中果园占75%+强降水影响)>耕地>城镇>草地>水域,输出强度城镇>耕地>林地>草地>水域;④RDA分析表明,年降水量(解释61.8%)和氮肥施用量(解释24.0%)是流域氮磷输出的主要驱动因子;⑤植被覆盖度与氮磷负荷呈弱负相关(r=-0.12),空间上正相关区位于东北/西北林地(高植被低干扰),负相关区集中于中西南耕地城镇(低植被高干扰)。【结论】林地是流域泥沙和氮磷污染负荷的主要来源,但耕地造成的氮磷污染应予以相当重视;在流域西南部及中部农业面源污染负荷较强的区域,若通过科学管理提高植被覆盖率,植被覆盖度每增加10%,总氮排放量可降低12.5%,但对总磷的影响较小。这一方法能够有助于缓解农业面源污染问题。本研究成果可直观展示出鉴江流域氮磷污染的空间分布,指导管理部门针对重点区域制定相关防治措施。
【Objective】Non-point source pollution in agriculture is a major threat to ecological and environmental systems in Guangdong Province,with prominent nitrogen and phosphorus loads found in the western part of the province.However,our understanding of the effects of vegetation on such pollution remains elusive.This paper aims to bridge this gap.【Method】The study area is the Jianjiang River Basin in western Guangdong.Using the SWAT model,we simulated the non-point source pollution from 2000–2020,from which we analyzed the spatiotemporal distribution and potential spatial sources of sediment,nitrogen and phosphorus in the region.Redundancy analysis was used to elucidate the effects of vegetation coverage,population,primary-secondary-tertiary industries,agriculture,forestry,livestock,fishery,as well as fertilizer and pesticide usage on total nitrogen and phosphorus loads.We specifically analyzed the correlation between vegetation coverage and non-point source pollution.【Result】①The SWAT model was satisfactory in simulating runoff,sediment and nitrogen-phosphorus processes in the basin,with R2/NSE>0.5.②From 2000 to 2020,the average annual water yield in the basin was 653 mm,the average annual sediment yield was 12321.4 tons,the average annual total nitrogen flux was 19629.4 tons,and the average annual total phosphorus flux was 5099.3 tons.③Land use affected nitrogen and phosphorus pollution,with their influence ranked in the order of forestland(70%total,with orchards contributing 75%+heavy rainfall impact)>cropland>build-up areas>grassland>water bodies;the contribution of different land uses to non-point source pollution was ranked in the order of build-up areas>cropland>forestland>grassland>water bodies.④The RDA analysis revealed that annual precipitation explained 61.8%and nitrogen fertilizer application explained 24.0%of the variation in the non-point source pollution of nitrogen and phosphorus in the basin.⑤On average,vegetation coverage and nitrogen and phosphorus loads were weakly correlated,with r=-0.12;spatially,they were positively correlated in forestlands in the northeast and northwest of the basin,and negatively correlated in croplands and urban areas in the central-southwestern parts of the basin.【Conclusion】Forestland was the primary source of sediment,nitrogen and phosphorus pollution,closely followed by cropland.Increasing vegetation coverage in high-pollution areas such as the southwestern and central parts of the basin can mitigate such pollutions.A 10%increase in vegetation coverage could reduce total nitrogen emissions by 12.5%,though its impact on total phosphorus pollution is limited.These findings provide a basis for targeted prevention and control of agricultural non-point source pollution in the basin.
作者
何丽
张秋英
李发东
刘洪光
额热艾汗
李兆
冷佩芳
李曹乐
HE Li;ZHANG Qiuying;LI Fadong;LIU Hongguang;E Reaihan;LI Zhao;LENG Peifang;LI Caole(College of Water Conservancy and Architectural Engineering,Shihezi University,Shihezi 832000,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China;Institution of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《灌溉排水学报》
2026年第1期114-127,共14页
Journal of Irrigation and Drainage
基金
高州市农业面源污染治理与监督指导试点项目(二次)(E22M2000AL)
高州市水生态环境保护治理总体技术服务项目(E22M2300AL)
乌兹别克斯坦节水减贫模式研究与示范项目(E4M40990AL)。
关键词
鉴江
SWAT
面源污染
时空分布
植被覆盖度
Jianjiang
SWAT
non-point source pollution
spatiotemporal distribution
vegetation coverage
