天然降雨条件下径流和磷素流失通量关系  

Relationship between runoff and phosphorus loss flux under natural rainfall conditions

作　　者：刘晓君 李占斌[2] 李鹏[2] 杨志 张铁钢[4] 任正龑 LIU Xiaojun;LI Zhanbin;LI Peng;YANG Zhi;ZHANG Tiegang;REN Zhengyan(College of Forestry, Jiangxi Agricultural University/Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, 330045, Nanchang, China;State Key Laboratory of Eco-hydraulic Engineering in Arid Area, Xi′an University of Technology, 710048, Xi′an, China;Soil and Water Conservation Monitoring Station of Ningxia Hui Autonomous Region, 750002, Yinchuan, China;Institute of Water Resources for Pastoral Area, MWR,010020, Hohhot,China)

机构地区：[1]江西农业大学林学院,鄱阳湖流域森林生态系统保护与修复国家林业和草原局重点实验室,南昌330045 [2]西安理工大学,西北旱区生态水利工程国家重点实验室培育基地,西安710048 [3]宁夏回族自治区水土保持监测总站,银川750002 [4]水利部牧区水利科学研究所,呼和浩特010020

出　　处：《中国水土保持科学》2022年第3期10-16,共7页Science of Soil and Water Conservation

基　　金：国家自然科学基金“红壤水稳性团聚体颗粒周转对淋溶过程养分迁移作用研究”(42107365);国家林业和草原局自主研发项目计划“黄河流域生态用水与林草植被格局优化配置”(LC606)。

摘　　要：磷素作为淡水生态系统中重要的限制性营养物质,其高度的空间异质性和复杂的流失特征,导致磷流失带来的非点源污染问题难以防治。为此以丹江小流域为研究对象,通过定位监测对比不同年份小流域各断面径流及磷素流失规律,探索天然降雨条件下径流磷素流失通量关系。结果表明:监测到的5场天然降雨,径流峰滞后时间分别在1~4 h之间;小流域总磷流失质量浓度范围为0.01~0.43 mg/L;随着小流域治理的年限增长,磷素流失质量浓度降低,水质整体向好;同一场次监测降雨内,随降雨的进行,小流域各断面总磷流失质量浓度先增大后减小,由上至下各断面总磷质量浓度呈现累积效应;与径流侵蚀功率(<0.60)相比,径流通量与磷素流失回归关系的决定系数(>0.90)更大;M(V)曲线表明监测到的不同场次天然降雨中,优先控制的磷素形态有所不同。径流通量是影响磷素流失的关键因子,尤其是不同降雨强度条件下径流通量对磷素流失的影响作用差异显著。[Background]Phosphorus(P)has high spatial heterogeneity and complex loss characteristics,which makes it difficult to prevent and control the non-point source pollution caused by soil erosion.As a major limiting element in the middle route of South-to-North Water Diversion Project,it is crucial to explore the law of P loss in the process of water and soil loss.[Methods]The characteristics of runoff flux,runoff erosion power,total P loss and available P loss in Danjiang watershed were analyzed by located monitoring of natural rainfall.The runoff samples of 6 sections were selected in 2 rainfall events in 2016 and 3 rainfall events in 2019 to analyze the runoff and P loss processes from upstream to downstream.The relationship between runoff flux,runoff erosion power and P flux was explored and compared under the condition of natural rainfall.[Results]The retardation time of runoff peak was 1-4 h;the P loss ranged from 0.01 to 0.43 mg/L.The average P concentration in runoff of 2016 and 2019 was 0.08 and 0.33 mg/L,respectively.The water quality improved with the increasing age of the small watershed management.If the rainfall intensity was lower,the total P loss in runoff was less,even though the precipitation was higher and during time was longer.This indicated that the P loss in runoff was more affected by rainfall intensity,rather than during time of rainfall and precipitation.In the same monitored rainfall,with the increase of rainfall duration,the concentration of total P loss at each cross section of the small watershed increased first and then decreased.The concentration of total P at each cross section showed a cumulative effect from top to bottom.When the rainfall intensity and I_(30)(maximum 30-min rainfall intensity)was high,the runoff erosion power could better reflect the P loss in runoff,while the determination coefficient was 0.59 with higher rainfall intensity and 0.26 for lower rainfall intensity.But under the condition of rainstorm,the regression coefficient of runoff flux and phosphorus loss(>0.90)w

关 键 词：天然降雨 径流 磷 通量 流失 

分 类 号：X522[环境科学与工程—环境工程]