【作者】 罗春燕；

【导师】 张维理；

【作者基本信息】 中国农业科学院 ， 植物营养学， 2008， 博士

【摘要】 农业面源污染是造成水体富营养化的重要原因,进行源解析,阐明农田和畜禽养殖等不同来源的氮磷流失量并据此进行分类控制是有效控制水体富营养化的基础。嘉兴地区地势低平、水田交错,农田或畜禽养殖场水量与氮磷流失量受周边水文条件影响大,小尺度定位监测很难获得有意义的观测结果。为了解大田、集约化农田和畜禽养殖场三种土地利用方式下氮磷流失特征,本研究选取可分别代表大田作物农田、集约化栽培作物农田、畜禽养殖场3种土地利用类型的7个具有代表性的平方公里尺度研究区,于2006年7月~2007年6月份汛期与非汛期总共进行了14次监测(其中大田1个点:汛期2次,非汛期1次;集约化农田3个点:汛期1~2次,非汛期1次;养殖场3个点:汛期1次)。在各定位研究区上,监测了河道水、沟渠水、水田田面水、沟渠底泥(沟渠底泥含水量忽略不计)与农田耕层土壤水分量和总量,研究了5种不同类型水体中氮、磷存量特征。对河道水、沟渠水、田面水研究了其总氮、水溶性总氮、硝态氮、铵态氮;对沟渠底泥研究了其0~5 cm表层土壤水溶性磷、Olsen P、矿质氮(硝态氮、铵态氮);对农田土壤研究了0~5 cm表层土壤水溶性磷、Olsen P和0~20 cm耕层土壤硝态氮、铵态氮。主要结论如下:7个研究区总水量平均为200.3千m3/km2,变化范围为83.7~944.7千m3/km2,相差11.3倍。4个农田研究区总水量汛期平均为198.7千m3/km2,变化范围为99.4~324.4千m3/km2;非汛期平均为174.9千m3/km2,变化范围为83.7~276.0千m3/km2,汛期与非汛期差异不大,仅相差1.1倍。河道水、沟渠水、田面水、0~20 cm、0~5 cm土层土壤水4种水体组分分别平均占总水量的69.6%、0.9%、2.0%、27.5%、7.7%。河道水是总水量的主要水体类型,0~20 cm土壤水次之。因此不同研究点位的河道水量和土壤水存量是引起总水量差异的主要因素。总水量、河道水、0~20 cm土层土壤水存量汛期与非汛期差异均不大,而沟渠水汛期是非汛期的1.7倍。7个研究区磷素总存量平均为933 kg/km2,变化范围为117~6220 kg/km2,相差53倍。畜禽养殖场、集约化农田类型研究区磷素总存量分别为760、1111 kg/km2,均高于大田(172 kg/km2),分别是大田的4.4倍、6.5倍。河道水总磷、沟渠水总磷、田面水总磷、沟渠0~5 cm底泥和0~5 cm土层土壤水溶性磷5个分量分别平均占磷素总存量的10.5%、0.4%、0.3%、0.1%、88.7%,研究区内农田0~5 cm土层土壤水溶性磷是磷素总存量的主要存在形式。7个研究区中农田0~5 cm土层土壤水溶性磷存量平均为958 kg/km2,变化范围为0~6167 kg/km2。畜禽养殖场、集约化农田类型研究区中农田0~5 cm土层土壤水溶性磷存量分别为270、1038 kg/km2,均高于大田(26 kg/km2),分别是大田的10.4、39.9倍;浓度分别为40.51、29.87 mg/kg,均远高于大田(0.79 mg/kg),分别为大田的51.3、37.8倍。大田和畜禽养殖场农田0~20 cm土层土壤矿质氮相差不大,但由于受畜禽养殖研究区中农田面积的较小,畜禽养殖研究区的土壤氮素存量仍低于大田研究区。3种类型研究区河道水总磷浓度大小顺序为畜禽养殖场>集约化农田>大田,沟渠水总磷浓度和沟渠底泥水溶性磷浓度与河道水总磷浓度一致。4个农田研究区的磷素总存量及河道水总磷、沟渠水总磷、田面水总磷、沟渠0~5cm底泥和0~5 cm土层土壤水溶性磷5个分量均表现为汛期高于非汛期,汛期分别是非汛期的1.5、2.2、2.1、1.2、1.4、1.5倍。7个研究区氮素总存量平均为14477 kg/km2,变化范围为3480~51555 kg/km2,相差14.8倍。畜禽养殖场、集约化农田、大田3种类型研究区氮素总存量分别为:3913、17082、5596 kg/km2,集约化农田研究区最高,大田次之,畜禽养殖场最小。河道水总氮、沟渠水总氮、田面水总氮、沟渠0~5 cm底泥和0~20 cm土层土壤矿质氮5个分量分别平均占氮素总存量的5.7%、0.2%、0.2%、0.2%、93.8%,0~20 cm土层土壤矿质氮是氮总存量的主要存在形式。7个研究区中农田0~20 cm土层矿质氮存量平均为13576 kg/km2,变化范围为0~50900 kg/km2。畜禽养殖场、集约化农田、大田3种类型研究区0~20 cm土层土壤矿质氮存量分别平均为:1143、16309、4635 kg/km2,集约化农田研究区最高,大田次之,畜禽养殖场最小;浓度平均分别为43.0、117.3、33.9 mg/kg,集约化菜地最高,是大田和畜禽养殖场的3.5倍。由于畜禽养殖研究区中农田面积关系,虽然大田和畜禽养殖场农田0~20 cm土层矿质氮相差不大,但是畜禽养殖研究区的土壤氮素存量低于大田研究区。4个农田类型研究区汛期的氮素总存量、河道水总氮存量、沟渠0~5 cm底泥和0~20 cm土层土壤矿质氮存量与非汛期的差异均不大,而沟渠水总氮存量是非汛期的1.7倍。更多还原

【Abstract】 Agricultural nonpoint source pollution is an important reason for water eutrophication, clarifying nitrogen and phosphorous loss from different source such as cropland and poultry farm is the effective base of controlling eutrophication. Jiaxing city is in lowland plain areas with crisscross network of river courses, and so the loss of N and P from cropland and poultry farm is affected strongly by the surrounding hydrology, which makes it very difficult to get significative result through small-scale investigation. In order to make clear of the characteristics of N and P loss from the three land use types, i.e. paddy-upland rotation field, intensive cropping field and poultry farm, we selected 7 representative experimental sites and monitored 14 times on square kilometer scale from July 2006 to June 2007, including 1 site paddy-upland field (flood season 2 times, non-flood season 1 time), 3 sites intensive cropping fields (flood season 1~2 times, non-flood season 1 time), and 3 sites poultry farm (flood season 1 time). Altogether, we monitored and calculated water quality of 5 different type: river water, channel water, soil surface water, channel sediment water, and topsoil water. We have also monitored total nitrogen, water soluble nitrogen, nitrate, and ammonium of river water, channel water and soil surface water. For channel sediment, we monitored water extractable P (WEP), Olsen P, nitrate, and ammonium nitrogen. For cropland soil, we monitored WEP and Olsen P of 0~5 cm topsoil, and mineral nitrogen (nitrate and ammonium N) of 0~20 cm topsoil. The main conclusions are as follows:The total water storage ranged from 83.7 to 944.7×103m3/km2, with an average of 200.3×103m3/km2 .The maximum of water storage was 11.3 times of that of the minmum. The average of the total water storage in four farmland study areas in the flood season and the non-flood season was 198.7×103m3/km2 (83.7~276.0×103m3/km2), 174.9×103m3/km2 (83.7~276.0×103m3/km2) respectively. The total water storage in four farmland study areas in the flood season was 1.1 times of that in the non-flood season. It was obvious that the average of the total water storage had little difference between in flood season and non-flood season. The water in rivers, ditch, soil surface water of paddy field, 0~20 cm and 0~5 cm soil layer averagely were respectively 69.6%, 0.9%, 2.0%, 27.5%, 7.7% of the total water storage. The river water was the main part, and 0~20 cm soil layer took second place. So the water in rivers and 0~20 cm soil layer were the main factor on the differentiation of the total water storage among the different study areas.The total P storage ranged from 177 to 6220 kg/km2, with a mean of 933 kg/km2. The maximum of total P storage was 53 times of that of the minmum.The total P storage in poultry farm (760 kg/km2) and intensive field (1111 kg/km2) was respectively 4.4, 6.5 times of that in paddy-upland rotation field (172 kg/km2).Proportion of the total P of river water, ditch water, soil surface water, WEP of sediment of ditch (0~5 cm) and soil layer (0~5 cm) for the total P storage were respectively 10.5%, 0.4%, 0.3%, 0.1%, 88.7%. The WEP of soil layer (0~5 cm) was the main existence form of the total P storage. Among the seven study areas, the average storage of the WEP of soil layer (0~5 cm) of farmland was 958 kg/km2, varing in the range of 0~6167 kg/km2. The WEP of soil layer (0~5 cm) of the farmland in poultry farm and intensive field was 270, 1038 kg/km2 respectively and were both higher than paddy-upland rotation field(26 kg/km2). The concentration of them was 40.51, 29.87 mg/kg, higher than paddy-upland rotation field (0.79 mg/kg). The storage of the WEP of soil layer (0~5 cm) of farmland was affected by the concentration and the total area of farm. Therefore, the storage of the WEP of soil layer (0~5 cm) of the farmland in poultry farm was less than in the intensive field because of its smaller farmland area, although its concentration of the WEP of soil layer (0~5 cm) was the highest in the three kinds of study areas.The order of the concentration of the total P in river water was: poultry farm> intensive field > paddy-upland rotation field. The WEP concentration of sediment of ditch and the total P concentration of ditch water were of the same order.The total P storage of four farmland study areas and river water, ditch water, soil surface water, the WEP of sediment of ditch (0~5 cm) and soil layer (0~5 cm) in the flood season were 1.5, 2.2, 2.1, 1.2, 1.4, 1.5 times of that in the non-flood season respectively.The total storage of N in seven study areas was 14477 kg/km2, varing in the range of 3480~51555 kg/km2. The maximum of total storage of N was 14.8 times of that of the minmum. The total storage of N in poultry farm, intensive field and paddy-upland rotation field study areas was respectively 3913, 17082, 5596 kg/km2. Proportion of the the storage of total N of river water, ditch water, soil surface water, Nmin of sediment of ditch (0~5 cm) and soil layer (0~20 cm) was respectively 5.7%, 0.2%, 0.2%, 0.2%, 93.8% of the total storage of N. The Nmin storage of soil layer (0~20 cm) was the main existence form of the total storage of N. The average Nmin of farm soil layer (0~20 cm) in seven study areas was 13576 kg/km2, varing in the range of 0~50900 kg/km2.The average Nmin of soil layer (0~20 cm) in poultry farm, intensive farm and paddy-upland rotation field study areas was 1143, 16309, 4635 kg/km2 respectively.The concentration of them was respectively 43.0, 117.3, 33.9 mg/kg. Although the difference of the Nmin of soil (0~20 cm) between paddy-upland rotation field and poultry farm was not great, the storage of soil N in poultry farm was less than the paddy-upland rotation field because of the farmland area.The difference of the total storage of N, storage of TN in river water, storage of Nmin in sediment of ditch (0~5 cm) and soil layer (0~20 cm) between in flood season and non-flood season was not great, but storage of TN in ditch water in flood season was 1.7 times of that in the non-flood season.更多还原