【作者】 袁东海；

【导师】 王兆骞；

【作者基本信息】 浙江大学 ， 生态学， 2002， 博士

【摘要】 我国是一个水土流失严重的国家，水土流失引起江河淤塞、洪水泛滥、养分流失、水体污染、土壤退化、土地生产力下降等一系列的环境问题，严重地影响了我国农业可持续发展，已引起人们普遍的关注。目前国内外学者有关水土流失的报道很多，但大多数以单一因素和模拟试验研究较多，而从生态系统角度出发，采用综合方法，在小流域尺度上研究水土流失规律较少；对小流域坡耕地综合农业措施水土保持效应和小流域综合开发利用过程中水土流失规律研究以及侵蚀土壤肥力评价的研究则更少。本研究选择浙江省中部金衢盆地边缘兰溪市水土保持监督站蒋家塘小流域为研究试验点，以协作单位兰溪市水土保持监督站小流域开发试验区为基础，采用坡面径流小区法、单源汇水试验区出口实测法、稳定性核素-Eu土芯示踪法研究了2000年坡耕地不同农作措施水土流失规律及养分流失规律和小流域综合开发过程中水土流失规律及养分流失规律，并对小流域侵蚀土壤的肥力现状进行评价。研究的主要结论如下： 1、运用坡面径流小区法系统地研究了当地农业生产活动中不同农作措施下红壤坡耕地水土流失特征、土壤养分流失规律及形态特征，结果表明： (1)同顺坡农作措施相比：其它农作措施均具有明显减轻水土流失的作用，等高土埂，等高农作、休闲处理控制水土流失的效果优于水平草带和水平沟处理。泥砂流失除等高土埂和等高农作以外，其它处理均是推移质流失量大于悬移质流失量。径流流失和泥砂流失主要集中在5～8月份，约占全年流失总量的80％以上，这与当地降雨季节性分配有关。 (2)不同农作措施径流小区有机碳、氮、磷、钾流失差异明显，有机碳、氮、磷、钾流失总量的顺序为：顺坡农作＞水平草带＞水平沟＞休闲＞等高土埂，同顺坡农作相比，其他农作措施均有减少有机碳、氮、磷、钾流失的作用，以等高土埂、等高农作、休闲处理减少土壤有机碳、氮、磷、钾流失的效果较好。 (3)侵蚀程度较轻，泥沙流失量较小，特别是推移质流失量较小的农作措施处理的径流小区，如休闲处理、等高土埂和等高处理的小区中有机碳流失以径流流失为主，相反，如水平草带处理、水平沟处理和顺坡农作处理的径流小区中，有机碳流 浙江大学博土学位论文 失以推移质流失为主。氮素的流失途径主要为径流流失，约占上壤氮素流失量 sl．9％～93．4％，在径流流失的氮素中又以水溶态氮素为主，约占径流流失氮素的 78％～87．6％，其中铰态氮含量略大于硝态氮，平均为 55．47％，而在推移质流失 的速效氮主要为铰态氮。推移质中有机碳和全氮均有富集现象。土壤有机碳、氮素 流失的时间主要集中在 5～8月份，约占全年流失总量的 83％以上。 （4）顺坡农作处理的径流小区通过椎移质流失的磷素和迈过径流流失的磷素基本 相当，其它处理的土壤磷素主要以径流方式流失，其流失量占土壤全磷流失量 67．59％～88．11％。在泥砂流失量较小的等高农作处理、等高土埂处理的坡耕地径 流小区中，土壤钾素主要以径流形式流失，其流失量占土壤钾素流失量分别为 刀．34％和65．79％；休闲处理处理的坡耕地径流小区通过径流流失的钾素和推移质 流失的钾素基本相当，而在泥砂流失量较大的顺坡农作处理、水平草带处理和水平 沟处理坡耕地径流小区土壤钾素主要以椎移质形式流失，其流失量占土壤钾素流失 量的比例分别为 62．27％、55．52％和 70．41％。土壤磷、钾素的流失主要为泥砂结 合态，推移质中不同形态的磷、钾素均有富集现象，特别是有效态磷、钾的富集程 度高于全磷、全钾的富集程度。与传统的顺坡耕作的坡耕地利用方式相比，其它种 不同农作措的均有减少和防治土壤磷、钾素流失的作用，以等高士埂、等高农作措 脑、休闲措施效果优于水平草带、水平沟农作措施。土壤磷钾素流失时间主要集中 在5月－巴月，占全年土壤磷、钾素流失量85以上％。 （5）影响径流和泥砂流失的主要因素为降雨量、降雨侵蚀力、植被覆盖度等因 素，影响土壤有机碳、氮、磷、钾流失的主要因素为降雨量、降雨侵蚀力、径流 量、泥砂流失量、植被状况和施肥状况． 2、从生态系统的角度出发，系统地研究了红壤小流域不同利用方式水土流失、养 分流失规律及其影响因素，并比较了红壤小流域不同利用方式保持水土和养分的效 应，结果表明： 们）红壤小流域不同利用方式的试验区（单源汇水试验区）水土流失、有机碳流 失主要集中在 5月、6月及 8月份，其间径流流失量占全年流失量的 68．78 ％～73．08 ％，泥砂流失量和有机碳流失量占全年流失量的90％以上。径流量和泥沙流失量 的大小顺序均为无保?更多还原

【Abstract】 Soil erosion in China is serious and causes ecological problems such as river jams, floods, nutrient loss, water pollution, soil degradation, and decrease in land productivity. It has negatively impacted on sustainable agricultural development, and this made many people pay attention. At present there are more reports on soil erosion by experts from home and abroad, but most of these reports were about simulation and research based on a single factor. There are little reports on soil erosion on entire watershed, adopted comprehensive research measures according to the principle of ecological system, especially on soil erosion from the intensive farming system on slope lands, watersheds exploited for agroforestry industry, as well as appraisal reports on soil fertility index. Soil erosion and nutrient losses in Jiangjiatang watershed in Lanxi city in Zhejiang province during exploitation was studied from 1993-2000 using adoptive research methods such as runoff plot, catchment area, and rare earth element tracer (Eu) , and the soil fertility index appraisal. The major conclusions are as follow:1. The principle of water and soil losses together with nutrients and the forms in which they were lost were studied under different fanning systems in runoff plot. The results show that(1) The system of contour dams, contours and fallow had positive impact on water and soil losses than grass stripes and contour ditch. At the same time it was showed that contour dams, contours, fallow significantly reduced soil erosion and water loss, grass stripe and contour ditch had recorded reduction in water and soil losses although to a much less extent than above 3 farming systems. Most of sediment was bed load in all the systems except in contour dams and contour fanning. The runoff and sediment deposition during the period May to August accounted for more than 80% of annual runoff and sediment deposit, this was due to the fact that during this period the area receives higher precipitation and rainfall. Additionally our findings were mat precipitation, rainfall index, plant coverage had impacted differently on runoff and deposit of sediment in different fanning systems.(2) The losses of organic carbon, nitrogen, phosphorus and potassium were different in different farming systems. This losses of these elements according to respective farming systems was the following order: tradition>grass stripe>contour ditch>fallow>contour dam. Compared with traditional fanning practices, others farmingsystems reduced losses of organic carbon, nitrogen, phosphorus and potassium and losses in contour dam, contour and fallow were much less than grass stripe and contour ditch.(3) The farming systems which had a less degree of soil erosion and sedimentation, organic carbon was lost mainly through runoff but in farming systems in which soil erosion was serious such as in grass stripe, contour ditch, traditional farming system, the loss was through bed load. Nitrogen loss through runoff was 81.9%-93.4% of the total. This loss through runoff comprised 78%-87.6% dissolved NHVN and NO"3-N although the former was slightly higher than latter as it made up 55.14% of the lost nitrogen. The quantities of organic carbon and nitrogen in the bed load were high than in the runoff plots and this had a nutrient enrichment phenomenon. The losses of organic carbon, nitrogen were concentrated in May to August accounting for more than 83%.(4) The percentage phosphorus loss by bed load was equivalent to mat lost as a result of runoff in traditional fanning practices, whereas in the rest of farming system the loss by runoff phosphorus was 67.59%-88.11%. Potassium lost by runoff in systems, which had less sedimentation such as contour, and contour dams, was 71.34% and 65.79% respectively of total. Potassium lost by runoff was equal to that lost by bed load in fallow farming system, but in the systems with more sediment such as traditional farming system, grass stripe, and contour ditch potassium loss was mainly through bed load whic更多还原