【作者】 胡宏祥；

【导师】 洪天求；

【作者基本信息】 合肥工业大学 ， 矿物学、岩石学、矿床学， 2008， 博士

【摘要】 巢湖位于安徽省中部,是中国五大淡水湖泊之一。20世纪80年代水体开始呈现富营养化状态,以后富营养化逐步加剧,现已演变成为全国富营养化最为严重的淡水湖泊之一。这严重影响了沿湖地区工农业生产发展和人民生活用水安全。虽然巢湖已经被列为国家重点治理湖泊之一,但到目前为止,巢湖水体富营养化状况依旧严重。造成这种现象的原因,是由于没有从根本上实行内源修复和外源防控的治理措施。而水土迁移作为非点源污染的主要途径和重要形式,可携带大量泥沙、氮、磷等物质进入巢湖水体,造成水体富营养化。本文通过对巢湖北岸典型地区水土迁移过程研究,揭示水土迁移和养分迁移的特征和规律,提出控制巢湖流域水土迁移的针对性措施,期望在治理巢湖水体富营养化过程中,能为外源防控决策提供理论依据和实际参考。本研究共分5个部分。第一部分,回顾分析水土迁移国内外研究进展和巢湖流域环境问题及研究状况。第二部分,通过野外调查和实验,对坡面土壤养分的时空变化和输出特征进行研究。第三部分,采用室内模拟实验,开展坡面径流、泥沙的产生过程和迁移规律研究,并对径流和泥沙中养分迁移过程和特征进行分析。第四部分,运用水土迁移模型和养分迁移模型,结合实测数据,进行水土迁移量和养分迁移量的估算和预测。第五部分,结合巢湖流域实际情况,对水土迁移的防控和治理技术进行了探讨。本研究取得如下成果:（1）野外调查和野外实验表明,由于水土迁移和养分迁移的影响,野外坡面土壤中氮磷元素含量总体上有随时间延长而降低,随空间高度增加而降低的趋势。在次降雨过程中,表层土壤中细小颗粒（粘粒和粉粒）与氮磷元素会移失,从而导致表层土壤中的养分含量都有不同程度的下降。其中,水解氮与速效磷的降低幅度较大（西瓜地、空闲地、油菜地水解氮和速效磷降雨前后降低幅度都在8.0%以上）,而全氮和全磷养分含量降幅很小（西瓜地、空闲地、油菜地全氮降幅分别为2.17%、1.86%和1.54%,全磷降幅分别为0.27%、0.22%和0.20%）。在不同利用方式下,降雨后田间表土细小颗粒（粘粒与粉粒）相对减少,粗大颗粒（砂粒）相对增多的幅度是不同的,表现出西瓜地最大,油菜地最小的特征。实验进一步证实,流失泥沙具有富集粘粒和养分的特征。表现在,油菜地、西瓜地和空闲地粘粒的富集率都达到1.20以上,全氮与速效磷的富集率都在1.28-1.39之间,全磷和水解氮富集率基本处在1.13-1.30之间。马鞍山坡面氮元素的富集率是1.26,磷素的富集率为1.15。通过对马鞍山坡面土壤和氮磷元素迁移量的监测和估算显示,土壤的平均迁移量为5412t/km²·a,土壤中氮元素和磷元素的平均迁移量分别为9.12t/km²·a和2.30t/km²·a。（2）首次利用巢湖北岸的主要土壤类型（黄棕壤、黄褐土、粗骨土）就坡面产流产泥沙过程和养分迁移过程进行了模拟实验。实验显示,坡面产流过程受降雨强度、坡面坡度、土壤类型、土壤前期含水量等因素的影响,坡面产流历时与降雨强度、坡面坡度、土壤前期含水量之间呈反相关,坡面产流量与降雨强度之间正相关,较大的稳定径流量出现时间与土壤前期含水量之间呈反相关;不同土壤类型,由于土壤质地和孔隙度等差异,坡面产流过程也不同。径流含沙量曲线变化特征是,在产流开始后逐渐上升,达到一个峰值后逐渐下降。其中,径流含沙量曲线的峰值出现时间与降雨强度、坡面坡度呈反相关;流失泥沙累积量与降雨强度、坡面坡度、径流累积总量之间呈正相关。坡面养分流失主要通过径流和泥沙两种形式来实现。其中,泥沙携带是养分迁移的主要形式。养分迁移总量与径流累积量、泥沙累积量之间都呈正相关。通过对黄褐土等的模拟实验还显示,流失泥沙中养分含量普遍高于原土壤对应的养分含量,即流失泥沙具有富集养分的特性。从三种土壤富集来看,粗骨土的富集率最高,黄褐土的富集率最低。从养分形态来看,三种土壤富集率大小规律总体是,速效磷＞水解氮＞全氮＞全磷。（3）用SCS径流曲线参数法对龟山地区水土迁移中的径流进行了研究和预测。预测结果是,研究区的年径流量为470.0mm。（4）采用侵蚀针法和USLE模型对龟山地区进行了土壤侵蚀量的估算或预测,结果分别是4107.57t/km²·a和3847.6t/km²·a,显示了两种预测结果基本一致性,但也显示了USLE模型法较侵蚀针法预测结果要稍微偏大的特点。（5）利用公式E=（Er₁^*S+Er₂^*Q）^*C,对研究区养分迁移量进行了计算。结果显示,利用SCS曲线法结合USLE模型预测研究区内氮素迁移量为8.027t/km²·a,磷素迁移量为2.903t/km²·a。其中氮和磷元素通过泥沙携带造成的损失占养分迁移总量的90.92%和90.36%,进一步证实泥沙携带是养分迁移的主要形式。（6）根据水土迁移和养分流失的研究,提出了针对巢湖周边的农耕技术、生物技术和工程措施相结合的水土迁移防控和治理措施。在低山丘陵区,应该采用植树种草为主的生物措施,重点进行土壤侵蚀的控制;在丘岗地区,通过农林复合生产、等高种植、等高梯田等措施,以达到截流保土的目的;而在冲积平原区,提倡保护性耕作和多层次缓冲带建设,达到重点控制污染物或养分流失的目的。最终从根本上控制外源污染物对巢湖的输入,实现逐步改善巢湖水质的目标。更多还原

【Abstract】 Lake Chaohu,located in middle of Anhui Province,is one of the five big fresh water lakes in China.In 1980s the water body of the lake started to present the eutrophication condition,later the eutrophication is intensified gradually,and it has already been evolved into one of most bad lakes,which has serious influence on industry,agriculture production and on the people’s living water security along lake area.Lake Chaohu is already listed as one of key lakes to control,but so far the eutrophication condition in Lake Chaohu remains severe.This phenomenon is due to no fundamental control measure to implement the endogene repair and the extraneous source prevention.Soil and water migration is the main way and the important forms to the nonpoint source pollution and it can also create the water eutrophication of Lake Chaohu through carrying large sediment,nitrogen,phosphorus and other substances into the water body.In this article water and soil transition process and rugularity in north shore of lake Chaohu are discussed.It is revealed that water and soil migration and the nutrient migration characteristic.And it is proposed the comprehensive measures to control water and soil migration in order to provide the theory basis and the actual reference for preventing and controlling the extraneous source pollution to Lake Chaohu.The study includes five parts.The first part is not only the review of research development about water and soil migration in the domestic and foreign but also the analysis of the question and the research condition about Lake Chaohu basin.The second part is involved in the field investigation and experimentation so as to study the temporal and spatial variation of soil nutrients and output characteristics of hillslope.In the third part the hillslope runoff,sediment and the nutrient transition process and the characteristic are researched by lab simulation experiment.In the fourth part it is discussed that the water and soil and nutrient migration prediction by applying water and soil transport model and nutrient transport model with experimental data.In the fifth part,according to the research foundation of the Lake Chaohu basin,the water and soil migration’s prevention technological measures are proposed.The research results are as follows: （1） The investigation and experimentation carried in the field show that nitrogen and phosphorus elements in the slope soil will be decreased in the overall with time and the altitude increasing,which is due to soil and water movement and migration of nutrients.In the process of rainfall,the clay,silt and the elements of nitrogen and phosphorus in the surface soil will migrate, so that the nutrient contents of the soil will decline.The declined ratio of hydrolysable nitrogen （＞7.5%） and rapidly available phosphorus（＞8.5%） is obvious,while that of total nitrogen （＜2.17%） is low and that of total phosphorus（＜0.27%） is lowest.The declined ratio of clay and silt and the increased ratio of sand are different with different land use after a rainfall,among which the change ratio in watermelon land is large,while in rape land is the small.The experiment further confirms that in sediment the clay and nutrient enrichment will occur.In watermelon land,rape land,and fallow land,the enrichment ratio of the clay is more than 1.20, and that of total nitrogen and rapidly available phosphorus is between 1.28-1.39,while that of the total phosphorus and hydrolysable nitrogen is basically between 1.13-1.30.The enrichment ratio of nitrogen is 1.26 and phosphorus 1.15 in Ma’anshan slope.Through monitoring and predicting, the transport estimation of soil is 5 412 t/km²·a,nitrogen is 9.12 t/km²·a,and phosphorus 2.30 t/km²·a in Ma’anshan slope.（2） The simulation test has been carried on by using yellow brown earth,yellow cinnamon soil,fragmental soil for the first time,which are the main soil types in the middle of the north shore of Lake Chaohu.Experiments show that the process of runoff on the slope is related to rainfall intensity,slope,soil type,reliminary moisture content of soil and so on.The emerging time of runoff is remarkably negatively interrelated with the rainfall intensity,the slope,the preliminary water content of soil.Slope runoff has positive correlation to the rainfall intensity. The emerging time of the maximum runoff is negatively interrelated with the preliminary water content of soil.Different types of soil have different process of runoff because they have different texture and porosity.The emerging time of the maximum content of sediments in runoff is negatively interrelated with rainfall intensity and the slope.The sum of sediment is remarkably positively interlated with rainfall intensity,slope,and runoff sum.The slope nutrient lost is taken by runoff and sediment.Among them,nutrient transfer taken by sediment is the main form.The sum of the nutrient migration is positively interlated with the sum of runoff and sediment.The simulation test by using three types of soil（yellow brown earth,yellow cinnamon soil, fragmental soil） also shows that:The content of nutrients in sediment is generally higher than that of the original soil,in another word,sediment has the characteristics of nutrient enrichment.The enrichment rate of fragmental soil is the large,while that of yellow brown earth is the small.On the forms of nutrient,the regularity of enrichment rate is:rapidly available phosphorus＞hydrolysable nitrogen＞total nitrogen＞total phosphorus.（3） In the studied area,the estimation of runoff is 470.0mm by utilizing SCS model.（4） The estimation of soil transportation is 4 107.57 t/km²·a by utilizing nailing,and 3 847.6 t/km²·a by utilizing USLE model,which demonstrates that the forecasting results have a basic consistency between nailing and USLE model.（5） Through using nutrient transportation formula E=（Er₁ ^*S+ Er₂ ^*Q）^*C,the forecast and estimation of nutrient transportation are conducted in the studied area.The results shows that the estimation of the nitrogen transportation is 8.027 t/km²·a and that of phosphorus is 2.903 t/km²·a. Nitrogen transportation in sediments accounts for 90.92%,and phosphorus transportation in sediments accounts for 90.36%,which further confirms that sediments carrying is the main form of nutrient loss.（6） On the basis of studying on soil and water transportation and nutrient transportation,the integration measures of the local farming technology,bio-technology and engineering is proposed to prevent and control the migration of water,soil,and nutrient in neighboring shore of Lake Chaohu.In hilly areas,by biological measures of planting trees and grass,in post areas,by agroforestry production,contour farming,contour terrace and other measures,in the alluvial plain areas,by conservation tillage and construction of multi-level buffer zone,the loss of pollutants or the nutrient could be controlled,which can fundamentally control the pollutants of the extraneous source to import to Lake Chaohu,so as to achieve a radical improvement of the water quality.更多还原