川中丘陵区(短)坡耕地耕作侵蚀及其对土壤生产力的影响

CORC > 成都山地灾害与环境研究所 > 中国科学院水利部成都山地灾害与环境研究所 > 成都山地所知识仓储（2009年以前）

题名	川中丘陵区(短)坡耕地耕作侵蚀及其对土壤生产力的影响
作者	苏正安
学位类别	硕士
答辩日期	2007
授予单位	中国科学院水利部成都山地灾害与环境研究所
授予地点	成都
导师	张建辉
关键词	川中丘陵区紫色土坡耕地 137Cs示踪技术梯级法耕作侵蚀土壤理化性质作物产量
学位专业	土壤学
中文摘要	在坡耕地景观内，由于农耕工具和重力作用而引起的耕作位移使土壤发生向下坡运动或向上坡运动（依赖于耕作方向），导致净余土壤量向下坡传输、堆积，重新分配，从而形成耕作侵蚀。紫色土区是我国水土流失最为严重的地区之一，仅次于黄土地区。通过梯级法、环境137Cs示踪技术和模型法研究表明耕作侵蚀是川中丘陵紫色土区线形（短）坡耕地的主要侵蚀形式之一，在中等坡度（8.97%～25.1%），耕作侵蚀速率为10.89～63.07 t/(hm2·a)，占总侵蚀速率的27.62%～48.64%；在陡坡（35.6%），耕作侵蚀速率为54.01 t/(hm2·a)，占总土壤侵蚀速率的87.49%，在显著较缓的坡面上占有更大的比例，甚至只有耕作侵蚀发生。耕作侵蚀主要发生在坡耕地的上部，从中部到下部耕作侵蚀主要表现为传输过程，在坡脚表现为堆积；在耕作侵蚀作用下，坡耕地的土壤剖面在坡顶最薄，坡脚最厚，从上坡向下坡逐渐增厚。耕作侵蚀在侵蚀、搬运和堆积这一系列过程中对土壤的机械组成、容重、有机质和土壤养分均产生影响：坡顶的熟土被侵蚀掉，土壤粘粒含量显著降低，土壤粗骨化，容重变大，土壤有机质和养分减少；从坡中至下坡耕作侵蚀使耕层土壤向下坡方向传输，体现为混匀作用，对土壤容重、机械组成、有机质和土壤养分的影响不大；在线形坡的坡脚部位，耕作侵蚀使土壤堆积，但是根据坡度和坡长以及是否有田埂的阻拦，水蚀既可能表现为堆积，也可能表现为侵蚀，即不同坡度的坡脚土壤在耕作侵蚀和水蚀的综合作用下可能处于堆积状态，也可能处于侵蚀状态，从而影响土壤机械组成、容重、有机质和土壤养分在坡脚分布。同时短坡耕地上的土壤理化性质在坡面上的分布和长坡的土壤理化性质在坡面的分布表现出明显不一致，短坡耕地上出现了变异的趋势，但是不具有统计学上的显著性，而在长坡耕地上，土壤理化性质的变异非常显著，这是由于短坡耕地上耕作侵蚀对土壤产生强烈的混匀作用，而长坡耕地上水蚀对土壤的分选性搬运的结果。在川中丘陵区紫色土（短）坡耕地上，耕作侵蚀对作物产量的影响也是非常显著的，造成坡顶作物产量和整个坡面的总产量降低。研究结果表明，耕作侵蚀在一定的景观范围内是十分严重的，其侵蚀速率和影响甚至超过了水蚀。因此，在国家实施的退耕还林还草，全面治理水土流失，加快生态环境修复重建的重大举措的今天，非农耕地的土壤流失已经初步得到了控制，农耕地的耕作侵蚀过程和机制的探索更显其重要的现实意义，在制定相应的土壤保持措施时，必须充分考虑耕作侵蚀的作用，才能有效地控制土壤侵蚀。
英文摘要	Tillage erosion, the net movement of soil downslope through the action of mechanical implements and gravity, results in net soil redistribution in the sloping field. Soil erosion, which was very serious on purple soil in the Sichuan Basin, China, was just less than that on the Loess Plateau. In this paper, the triangle step profile method, 137Cs technique and tillage erosion model were used to research the contribution of tillage erosion to total soil erosion, meanwhile, the effects of tillage erosion on soil and crop production properties were also studied on short slope in the Sichuan Basin, China. The results showed that tillage erosion usually occurs on the crest and upper slope positions and the soil accumulates at down slope positions. The tillage erosion rate ranges from 10.89 to 63.07 t/(hm2.a) and accounts for 27.62%～48.64% of total erosion rate on the slopes with the gradients of 8.97%～25.1%. Meanwhile, on the steep slope (35.6%), the tillage erosion rate is 54.01 t/ (hm2.a) and accounts for 87.49% of total erosion rate and the tillage erosion rate accounts for almost 100% of total erosion rate on the slow slope. Tillage erosion is the dominant erosion process on the crest and upper slope. The tillage layer under tillage erosion became thinner on the crest slope positions, while it became thicker from the midst to foot of slopes.Tillage erosion, which caused the clay contents, soil organic matter and soil nutrients decreasing at the top of slope while increasing at the down slope positions, made the soil quality become worse at the top of the slope, the soil mix from midst of slope to down slope and become better at the foot of slope. However, the distribution in soil clay contents, soil organic matter and soil nutrients on short slope was not significant different among different slope segments, while the differences was significant between different slope segments on long slope, indicating there were difference erosion between short slope and long slope. The crop yields on the crest of slopes were much less than that on the midst and foot of slopes, indicating that tillage erosion had important effects on crop yields in the sloping fields. The loss of crop yields at the top of slope was much more than the increase of crop yields at the foot of the slope under tillage erosion, suggesting the less crop yields were got on the whole slope. The results showed that tillage erosion was one of the important erosion processes in the Sichuan Basin and would be more severe than water erosion in some landscape positions. Therefore, the prevention and cure the soil loss from sloping field has very important effect on soil and water conservation. Because the adverse effect of tillage erosion was neglected in the slope field in the west region, China, therefore it is important to correctly assess the process and mechanism of tillage erosion and make the proper planning to combat soil and water conservation
语种	中文
学科主题	土壤学
公开日期	2010-10-21
分类号	S15;S34
内容类型	学位论文
源URL	[http://ir.imde.ac.cn/handle/131551/2280]
专题	成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前）成都山地灾害与环境研究所_山地灾害与地表过程重点实验室
推荐引用方式 GB/T 7714	苏正安. 川中丘陵区(短)坡耕地耕作侵蚀及其对土壤生产力的影响[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2007.