IMHE OpenIR  > 山地表生过程与生态调控重点实验室
干热河谷区坡面水蚀与耕作侵蚀的交互作用机制
Alternative TitleMechanism of interactions between tillage erosion and water erosion in the dry-hot valley region
张泽洪
Subtype博士
Thesis Advisor张建辉
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline土壤学
Keyword耕作侵蚀 水蚀 磁性示踪 水土流失 交互作用
Abstract干热河谷坡耕地土壤侵蚀是金沙江侵蚀产沙的主要策源地,耕作侵蚀与水蚀是坡耕地两大主要侵蚀类型。尽管其各自侵蚀过程与机理已有较多认识,但是二者耦合作用机制还缺乏,特别是耕种侵蚀加速或者减弱水蚀争议较大,水蚀对耕作侵蚀的作用研究也还未涉及。为了研究耕作侵蚀对水蚀的作用机制,探讨水蚀对耕作侵蚀是加强还是削弱作用的问题,本文以金沙江干热河谷典型坡耕地为研究对象,采用磁性示踪、冲刷试验、模拟耕作、3D激光扫描技术、地统计学分析及数理统计分析相结合的方法,系统研究了干热河谷坡耕地耕作侵蚀与水蚀的交互作用机制,本研究取得以下主要结论:1、坡耕地耕作侵蚀的空间分布特征不同土壤类型的模拟耕作试验结果显示,砾石土的平均耕作侵蚀速率(59.49 Mg ha-1 tillage pass-1)明显低于燥红土耕作侵蚀速率(91.99 Mg ha-1 tillage pass-1)(P < 0.05),黄棕壤平均耕作侵蚀速率大于砾石土耕作侵蚀速率而小于燥红土耕作侵蚀速率。在坡度3°-35°范围内,砾石土的耕作位移与坡度呈线性增加关系,而在坡度35°以上则呈指数增加趋势,说明35°是砾石土耕作位移突然增大的休止角。砾石土和燥红土25°以下坡耕地耕作侵蚀速率明显小于25°以上侵蚀速率。说明坡耕地耕作侵蚀不仅在不同土壤间表现出差异,也在同种土壤不同坡度间存在明显差异。2、侵蚀区耕作位移对水蚀的影响通过在径流小区侵蚀区(上坡)模拟不同耕作侵蚀强度,冲刷试验结果表明,坡面起始产流时间变化规律为:耕作11年(45'18'')>耕作22年(36'35'')>耕作32年(32'27'')>耕作38年(23'30'')>耕作43年(11'21''),不同耕作年限的累计产流量、平均产流率和输沙率变化呈现出随耕作年限的增加而增大的趋势;累计产沙量变化规律为:耕作43年(10385 g)>耕作38年(8960 g)>耕作32年(7118 g)>耕作22年(6375 g)>耕作11年(3598 g);与参考地相比,平均每增加一次耕作,土壤侵蚀速率增大106 kg ha-1,以上结果表明随着耕作强度的增强,坡面产流越快,产流产沙量也相应增大,揭示了耕作侵蚀加速了燥红土区坡耕地土壤水蚀作用。坡面累计产流量和累计产沙量随降雨强度的增大而增大,也随坡度的增加而增大,表明降雨强度和坡度的增大进一步促进了坡面耕作侵蚀对水蚀的作用。3、沉积区耕作位移对水蚀的影响通过沉积区(下坡)模拟不同填沟耕作位移量,试验结果显示,坡面起始产流时间随耕作位移量的增大而延长,不同耕作位移量的累计产流量和平均产流率变化规律为:21 kg m?1<12 kg m?1<0 kg m?1,但是平均输沙率和累计产沙量则呈现相出随耕作位移量的增大而增大的变化规律,与全沟相比,耕作填半沟土壤侵蚀产沙增大766 kg ha?1,耕作填全沟土壤侵蚀产沙增大951.5 kg ha?1,这表明沉积区耕作位移量的增加减小了坡面产流,但是加剧了坡面水蚀。这主要归因于耕作位移量增加尽管增大坡面径流入渗,减小了坡面产流,但为坡面流侵蚀提供松散的物源也越多,表明沉积区耕作位移量增大,促进坡面产沙。不同坡度的平均产流率和输沙率呈现出:5°< 10°<15°的变化规律,累计产流量和产沙量的坡度变化也表现出了相同变化趋势,表明坡度的增大进一步促进了坡面耕作侵蚀对水蚀的作用。不同耕作位移量的平均流速变化规律为:0 kg m?1(46.55 m min-1)>12 kg m?1(43.07 m min-1) > 21 kg m?1时(30.29 m min-1),全沟填土的平均径流剪切力大于半沟填土,不同坡度的径流剪切力变化趋势为:15°(41.71 Pa)>10°(24.01 Pa)>5°(14.62 Pa) 。这些变化趋势表明,耕作位移量的增大相应增大了径流剪切力,从而增强了坡面径流侵蚀力;坡度的增加也增大了坡面径流剪切力,进一步促进了坡面径流侵蚀力,揭示了耕作侵蚀通过增大坡面径流流速和径流剪切力,促进坡面产沙,加速坡面水蚀。4、水蚀对耕作侵蚀的作用在坡耕地上,采用磁性示踪法,完成不同水蚀强度的模拟耕作试验,结果显示,中度水蚀、强烈水蚀和极强烈水蚀的耕作侵蚀速率比没有水蚀作用时的耕作侵蚀速率分别大60.65%、74.74%、155.17%;耕作侵蚀速率变随水蚀强度的增大而增大,表明坡耕地坡面水蚀作用加剧了耕作侵蚀。中度水蚀作用下,在测定坡度范围,耕作侵蚀速率随着坡度增加而增大,坡度的增大进一步促进了水蚀对耕作侵蚀的加剧作用。中度水蚀时的顺坡耕作和等高耕作的耕作侵蚀速率均比无水蚀作用时大,而逆坡耕作时则在上坡位发生沉积并且与无水蚀作用时相近,说明顺坡耕作和等高耕作均会加大水蚀对耕作侵蚀的影响,采用逆坡耕作作则能有效避免水蚀对耕作侵蚀的作用,这为水蚀区坡耕地减小水蚀作用对耕作侵蚀的影响提出了很好的水土保持措施建议。5、耕作侵蚀与水蚀交互作用的空间格局坡耕地耕作侵蚀加剧了坡面水蚀,降雨强度和坡度的增大进一步促进耕作侵蚀对水蚀的加剧作用,而坡面水蚀又反过来增强耕作侵蚀,坡度的增大进一步加剧水蚀对耕作侵蚀的影响,因此,干热河谷区坡耕地耕作侵蚀与水蚀以相互促进机制影响坡面土壤侵蚀。干热河谷区坡耕地耕作侵蚀与水蚀交互作用的空间格局表现在垂直差异和水平差异,垂直差异表现在:东川干热河谷区坡脚砾石土坡耕地耕作侵蚀与水蚀相互促进作用效应小于坡顶黄棕壤;元谋干热河谷区坡脚燥红土坡耕地耕作侵蚀与水蚀相互促进作用效应大于坡顶紫色土,坡耕地耕作侵蚀与水蚀相互促进作用随坡度增大而增大。水平差异表现在:元谋干热河谷区燥红土坡耕地的耕作侵蚀与水蚀相互促进作用效应大于东川干热河谷区的砾石土,而东川干热河谷区黄棕壤坡耕地的耕作侵蚀与水蚀相互促进作用效应大于元谋干热河谷区的紫色土。 
Other AbstractSoil erosion of sloping farmland in the dry-hot valley is the main source of sediment yield in Chin-sha River, water and tillage erosion, two erosion processes, contributed to the total soil erosion in steeply sloping regions. Although their erosion process and mechanism were understood better, the coupling mechanism is lack, especially the acceleration or diminishment of tillage erosion on water erosion is controversial and relative study on interaction mechanism of water and tillage erosion has not been carried out until now. To research the effect of tillage erosion on water erosion and explore if water erosion accelerate or weaken tillage erosion, the magnetic tracer method, scouring experiment, simulated tillage by hoeing, 3D laser scanning technology, and combining geostatistics analysis and mathematical statistic were used to examine systematically interaction mechanism of water and tillage erosion on sloping farmland in the dry-hot valley. The main results and conclusion are as follows:1. Spatial distribution characteristics of tillage erosion Simulation tillage experiments in different soil types indicate that there was an increasing linear relationship between slope and tillage displacement in the range of grade 3 ° to 35 °, but an exponential increase more than 35°, which indicated that 35° was the critical angle of repose for sudden increase of tillage displacement in gravel soils. In the range of grade 3 ° to 25 °, tillage erosion rates of gravel soil and Torrid red soil were significantly less than that of 25 ° above (p < 0.05). In all slope range, average tillage erosion rates of gravel soil (59.49 Mg ha-1 tillage pass-1) was significantly (p < 0.05) less than that of Torrid red soil (97.14 Mg ha-1 tillage pass-1), but no significant difference was found between both soils and yellow brown soil. These results indicate that tillage erosion rates of gravel soils at the foot of valley slopes significantly were less than that of Torrid red soil, and two soil types have low tillage erosion rates under the range of 25°. The above results show that there not only exists significant difference in different soils but among different slope of the same soil2. Effect of tillage displacement in erosion positions on water erosion With simulation of different tillage intensities at the upper slope positions in runoff plots, the results of the scouring experiments at the same flow discharge show that runoff started time from the experimental plot after the initiation of the scouring: 11 year tillage(45'18'')> 22 year tillage(36'35'')> 32 year tillage(32'27'')> 38 year tillage(23'30'')> 43 year tillage(11'21''). Cumulative runoff amount presented an increasing trend with increasing tillage periods, which indicated that the greater the tillage intensity is the faster and greater runoff. Mean runoff rates and sediment rates increased with increasing tillage periods. Cumulative sediment amounts for different tillage periods were as follow: 43 year tillage > 38 year tillage > 32 year tillage > 22 year tillage > 11 year tillage. Soil erosion rate increased by 106 kg ha-1on average each additional tillage, compared with the conference site. The runoff and sediment amounts significantly increased with increasing tillage intensity, showing that soil redistribution by tillage erosion in upslope positions accelerated water erosion. At 32 year tillage, cumulative runoff and sediment amounts increased with increasing flow discharge and slopes, suggesting that the increase of flow discharge and slopes further promoted the effect of tillage erosion on water erosion.3. Effect of soil flukes in depositional positions on water erosion Different soil fluxes were simulated in 10° runoff plots, the results about the scouring experiment of same flow discharge show that runoff started time from the experimental plot after the initiation of the scouring: 21 kg m?1 ( 35'15'') >12 kg m?1 (28'31'') >0 kg m?1 ( 21'28''). Mean sediment rates and cumulative runoff amounts also increased with increasing soil fluxes, However, cumulative runoff amounts and mean runoff rates decreased with increasing soil fluxes: 21 kg m?1<12 kg m?1<0 kg m?1, suggesting that increase of soil fluxes decreased slope runoff, but increased sediment amount. This is attributed to the fact that increase of soil fluxes increased soil infiltration and decreased surface runoff. However, more soil fluxes supply more loose soils for water erosion, implying that infilling of rills by tillage erosion in downslope positions increased slope sediment. In other words, infilling rills by tillage provided a great deal of material resources for water erosion. For the soil flux of 12 kg m?1, detachment and runoff amounts were as follow: 5° < 10°< 15°, showing that the increase of slopes further promoted the effect of soil fluxes on water erosion.The changing trend of mean flow velocity for different soil fluxes was as follow: 0 kg m?1>12 kg m?1>21 kg m?1. Mean runoff shear stress increased with increasing slope gradient: 15° (41.71 Pa)>10° (24.01 Pa)>5° (14.62 Pa). Soil erosion rate for 12 kg m?1 and 21 kg m?1 increased by 766 kg ha?1 and 951.5 kg ha?1 respectively, compared with the soil fluxes for 0 kg m?1. These results showed that increase of soil fluxes increased soil infiltration and runoff shear stress, thus increasing runoff eroding force. The scouring experiment showed that increase of slope gradient also increased the hydrodynamic parameter (including mean flow velocity, runoff depth, and effective shear stress), and further promoted runoff eroding force and enhanced water erosion.4. Effect of water erosion on tillage erosion A series of simulated tillage experiments for different water erosion intensities were carried out with magnetic tracer method on sloping farmland. This result shows that tillage erosion for slight, medium and strong water erosion were greater by 60.65%, 74.74% and 155.17% than those under no water erosion, respectively. The changing trend of tillage erosion rates in different water erosion intensities were as follow: extemely intensive water erosion > intensive water erosion > medium water erosion, suggesting that water erosion on sloping farmland accelerated tillage erosion. In measured slope range, tillage erosion rates under medium water erosion increased with increasing slope gradient, showing that increase of slope gradient further enhanced effect of water erosion on tillage erosion. Tillage erosion rates for downward tillage and contour tillage under water erosion were greater than that under no water erosion, but tillage erosion for upward tillage was close to that under no water erosion. This indicates that downslop tillage and contour tillage can accelerate effect of water erosion on tillage erosion, but upslope tillage can effectively restrained it, which proposing a fine measures and suggestions about water and soil conservation for reducing the effect of water erosion on tillage erosion in sloping farmland.5. Spatial patterns of interaction mechanism of water and tillage erosion According to the research results of interaction mechanism of water and tillage erosion, tillage erosion accelerated water erosion, which can be further strengthened by the increase of rainfall intensity and slope. In turn, water erosion can contribute to tillage erosion, which can be further enhanced by the increase of slope. Therefore, water and tillage erosion affected slope soil erosion with mechanism of mutual promotion on sloping farmland in the dry-hot valley.Spatial patterns of interaction mechanism of water and tillage erosion showed the vertical and horizontal difference. The Vertical difference shows that interaction effect of tillage erosion and water erosion on sloping farmland is different in region. The horizontal difference presented that interaction effect of tillage erosion and water erosion on Torrid red soil sloping farmland in Yuanmou dry-hot valley is greater than that of gravel soil sloping farmland in Dongchuan dry-hot valley, but greater that on yellow brown soil sloping farmland in Dongchuan dry-hot valley than that on purple soil sloping farmland in Yuanmou dry-hot valley. 
Pages149
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24602
Collection山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
张泽洪. 干热河谷区坡面水蚀与耕作侵蚀的交互作用机制[D]. 北京. 中国科学院大学,2017.
Files in This Item:
File Name/Size DocType Version Access License
干热河谷区坡面水蚀与耕作侵蚀的交互作用机(4536KB)学位论文 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[张泽洪]'s Articles
Baidu academic
Similar articles in Baidu academic
[张泽洪]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[张泽洪]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 干热河谷区坡面水蚀与耕作侵蚀的交互作用机制.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.