胡家山小流域农田土壤氮磷收支研究

发布时间：2018-04-14 13:30

本文选题：胡家山小流域 + 土壤表观平衡模型　；参考：《华中农业大学》2015年硕士论文

【摘要】：南水北调中线工程水源地--丹江口水库,作为全国最大的饮用水源保护区,对水质要求极高,同时确保一江清水向北流,也是南水北调中线工程成败的关键。然而,水源区跨湖北、河南和陕西三省,82.1%的居民生活在农村,贫困人口296.2万人,40个县中有26个为国家级贫困县,农村发展与水源地保护矛盾依然突出。长江流域水土保持监测中心监测数据显示:水源区水土流失面积39515.4km2,占土地总面积45%,年土壤侵蚀量1.69亿吨,侵蚀模数达3572吨/(km2?a)。伴随水土流失而携带的氮磷等污染物对水库水质产生严重影响。因此,面源控制在丹江口水库水质保护中至关重要。面源污染归根结底是养分在时空过程上的“收支”失衡造成的,降低面源污染形成的危险最可靠的方法是控制污染物来源。因此,控制面源污染的形成的重要途径之一是力求使土壤中的养分达到盈亏平衡,如果养分输入输出达到平衡,将不会产生富裕的养分物质,在降雨径流过程发生时不会有养分流失,因而不会形成面源污染。本文选取丹江口库区典型小流域一胡家山小流域作为研究区,基于土壤表观养分平衡模型,通过农田调查获取基础数据,对小流域内农田土壤氮磷收支进行研究,结合GIS对该流域种植结构、氮磷平衡强度及空间特征进行了分析,并对其流失风险及污染潜势进行了评价,得出如下结论:1、胡家山小流域各个集水区均表现为化肥氮磷为农田土壤表观氮磷输入的主要来源,其次为其他氮磷输入、有机肥氮磷输入。因此,要想实现流域内土壤表观氮磷平衡,重点是加强对农田化肥投入的管理。2、胡家山小流域各个集水区农田表观土壤氮磷均表现为盈余,2012年农田土壤磷流失风险性及2013年农田土壤氮、磷流失风险性均是集水区9最高,2012年农田土壤氮流失风险性及2013年农田土壤氮、磷流失风险性均是集水区12最低,综合评价得出,胡家山小流域农田土壤养分流失风险性集水区9最高,集水区12最低。3、胡家山小流域各个集水区农田土壤表观单位面积氮磷素平衡表现出明显的空间差异性,从整个区域看,近两年氮盈余趋势基本表现为胡家山小流域中偏西部水系沿线集水区及东南边界集水区总体上高于其他集水区。中偏东部水系沿线集水区氮素盈余量最低。磷素盈余趋势基本表现为胡家山小流域中西部水系沿线集水区总体上高于东部沿线水系集水区。氮、磷素盈余均为种植业驱动型养分盈余,农田施用化肥是造成土壤表观氮、磷素盈余的主要原因。4、2012年和2013年胡家山小流域农田土壤表观氮盈余总量分别为88.4 t/a和88.8 t/a,氮盈余负荷分别为167 kg/(hm2*a)和168 kg/(hm2*a),均低于流失风险值180 kg/(hm2*a),但高于全国均值154 kg/(hm2*a)。2012年和2013年农田土壤表观磷盈余总量分别为18 t/a和15 t/a,磷盈余负荷分别为34 kg/(hm2*a)和29kg/(hm2*a),均低于流失风险值35kg/(hm2*a),但高于全国均值26.1 kg/(hm2*a)。农田土壤氮磷素的污染潜势已经形成。
[Abstract]:Ntransfer -- Danjiangkou reservoir, as the country's largest protected area of drinking water sources, water quality is extremely demanding, at the same time to ensure a clean water to the north, is also the key success of Middle Route Project of South to North Water Diversion Project. However, the water source area across Hubei, Henan and Shaanxi provinces, 82.1% of the residents living in rural areas, poverty 2 million 962 thousand one of the 40 counties, 26 national poverty counties, the protection of water sources in rural development and contradictions are still outstanding. The monitoring center monitoring data show that soil and water conservation in the Yangtze River Basin area 39515.4km2: soil erosion source area, accounting for 45% of the total land area, annual soil erosion amount of 1.69 tons, the erosion modulus of 3572 tons / (km2? A). While the nitrogen and phosphorus pollutants carried a serious impact on the water quality of the reservoir with water and soil erosion. Therefore, non-point source pollution control is very important in the protection of the water quality of Danjiangkou reservoir. The non-point source pollution to the root node is in nutrient The "balance" of space imbalance, reduce the risk of non-point source pollution in the most reliable method is to control the formation of pollutant sources. Therefore, one of the important ways for the formation of the non-point pollution control is to make the soil to reach breakeven, if the balance of nutrient input and output, will produce a nutrient rich not in the rainfall runoff process, there will be no nutrient loss, and thus will not form non-point source pollution. This paper selects a typical small watershed of Danjiangkou reservoir area hujiasha small watershed as the study area, apparent soil nutrient balance model based on the basic data obtained through the investigation of farmland, small watershed, soil nitrogen and phosphorus balance, combined with GIS planting structure of the basin, nitrogen and phosphorus balance intensity and spatial characteristics are analyzed, and the risk of loss and pollution potential were evaluated, draws the following conclusion: 1, Hu Jia Mountain small watershed in each catchment were apparent as the main source of nitrogen and Phosphorus Input of farmland soil nitrogen and phosphorus fertilizer, followed by other nitrogen and phosphorus input, organic fertilizer nitrogen and phosphorus input. Therefore, in order to achieve the basin apparent soil nitrogen and phosphorus balance, the focus is to strengthen the management of chemical fertilizer input in.2, Hu Jiashan each small watershed catchment farmland apparent soil nitrogen and phosphorus were surplus, soil nitrogen and soil phosphorus loss risk of farmland in 2013 of 2012, P loss risk are the 9 watershed highest 2012 farmland soil nitrogen loss of soil nitrogen and phosphorus loss risk of farmland in 2013, the risk is 12 watershed comprehensive evaluation of the minimum. Hujiasha small watershed, soil nutrient loss risk of watershed 9 is the highest, the lowest.3 12 watershed, hujiasha small watershed in each catchment soil apparent nitrogen and phosphorus balance per unit area showed obvious spatial difference Specifically, from the regional perspective, the nitrogen surplus trend in recent years is basically hujiasha small watershed in the Middle West River watershed and watershed along the southeastern boundary is generally higher than the other in the east along the river watershed. The watershed nitrogen surplus. The lowest phosphorus surplus trend to the overall performance of hujiasha small watershed along the rivers catchment is higher than the Midwest along the eastern River watershed. Nitrogen, phosphorus surplus for planting industry driven nutrient surplus, farmland fertilizer is caused by apparent soil nitrogen, phosphorus surplus of the main reason of.42012 and 2013 Hu Jia mountain farmland soil apparent nitrogen total earnings were 88.4 t/a and 88.8 t/a respectively, the nitrogen surplus load 167 kg/ (hm2*a) and 168 kg/ (hm2*a), the risk of loss were lower than the value of 180 kg/ (hm2*a), but higher than the national average of 154 kg/ (hm2*a).2012 and 2013 soil apparent phosphorus surplus The total amount is 18 t/a and 15 t/a respectively, and the phosphorus surplus load is 34 kg/ (hm2*a) and 29kg/ (hm2*a), respectively, which are lower than the loss risk 35kg/ (hm2*a), but higher than the national mean 26.1 kg/ (hm2*a). The pollution potential of farmland soil nitrogen and phosphorus has been formed.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153.6

【参考文献】