發(fā)布時(shí)間：2018-04-03 00:23

  本文選題：黃土高原　切入點(diǎn)：耕作措施　出處：《西北農(nóng)林科技大學(xué)》2016年碩士論文

【摘要】：地表糙度是認(rèn)為土地管理和土壤侵蝕共同作用的結(jié)果,它常常造成地表高低起伏和凹凸不平,嚴(yán)重影響地表徑流和侵蝕過程。細(xì)溝侵蝕是坡面土壤侵蝕的主要方式之一,細(xì)溝侵蝕是指坡面流匯集成股流后對(duì)地表沖刷作用下在坡面形成細(xì)小侵蝕溝的現(xiàn)象,主要包括水流對(duì)土壤的分離、沖刷和搬運(yùn)過程。地表糙度的形成可以直接或間接的影響細(xì)溝的形成、發(fā)展以及細(xì)溝侵蝕量的大小。本文以黃土高原普遍采用的等高條播、等高點(diǎn)種、人工鋤耕和等高等高犁耕管理措施的坡耕地為研究對(duì)象,平整坡為對(duì)照組。使用楊凌地區(qū)的X土,選取不同坡度(3°、5°、10°、15°和20°)、不同雨強(qiáng)(60mm/h、90mm/h和120mm/h)和四種不同耕作措施(等高犁耕、人工鋤耕、等高條播和等高點(diǎn)種),通過室內(nèi)外的人工降雨實(shí)驗(yàn)分析不同地表糙度的侵蝕產(chǎn)沙特征;不同地表糙度對(duì)細(xì)溝的形成、發(fā)育過程的影響,以及對(duì)細(xì)溝侵蝕量的影響關(guān)系研究。主要結(jié)論如下:(1)四種不同的耕作措施產(chǎn)生不同的地表糙度,大小依次為等高條播等高點(diǎn)種人工鋤耕等高犁耕CK。相同耕作措施、相同雨強(qiáng)下,侵蝕產(chǎn)沙量隨著坡度的增大而增大;相同坡度和雨強(qiáng)下,隨著地表糙度的增大侵蝕產(chǎn)沙量減小(等高點(diǎn)種除外)。但是在降雨過程中存在一個(gè)臨界的坡度,使得地表糙度由增加侵蝕作用轉(zhuǎn)變?yōu)闇p小侵蝕作用,這個(gè)臨界坡度隨著地表糙度的增大而減小。通過單因素方差分析得出坡度(S)、雨強(qiáng)(P)、地表糙度(RR)對(duì)侵蝕產(chǎn)沙量(Es)的影響均是顯著的,且四者的關(guān)系為Es=0.2654P+0.3941S-0.3822RR-0.0528(R2=0.7189)(2)隨著地表糙度的增大,細(xì)溝產(chǎn)生的時(shí)間越晚;降雨過程中每個(gè)小跌坎的位置都分布在坡面的中下部,具體位置具有隨機(jī)性,與地表糙度無關(guān)。細(xì)溝發(fā)育的過程表現(xiàn)為小跌坎—下切溝頭—斷續(xù)細(xì)溝—連續(xù)細(xì)溝,細(xì)溝的最長溝長在不同的耕作措施下的大小依次為等高犁耕人工鋤耕等高條播等高點(diǎn)種,細(xì)溝深度和平面密度有相似的變化趨勢。細(xì)溝侵蝕量與坡度呈極顯著的指數(shù)相關(guān)關(guān)系;在同一雨強(qiáng)同一坡度下,細(xì)溝侵蝕量隨著地表糙度的增大呈減小趨勢(等高點(diǎn)種除外),二者呈顯著的二次多項(xiàng)式關(guān)系。通過單因素方差分析得出坡度(S)、雨強(qiáng)(P)、地表糙度(RR)對(duì)細(xì)溝侵蝕量(Er)的影響均是顯著的,且四者的關(guān)系為Er=0.2338P+0.4320S-0.1108RR-0.0789(R2=0.6573)。
[Abstract]:Surface roughness is the result of the interaction of land management and soil erosion, which often results in high and low surface fluctuation and uneven surface, which seriously affect the surface runoff and erosion process.Rill erosion is one of the main ways of soil erosion on slope surface. Rill erosion refers to the formation of small erosion gullies on the slope surface under the action of scouring the surface of the slope after the flow converges into a stream, which mainly includes the separation, erosion and transport of soil by water.The formation of surface roughness can directly or indirectly affect the formation, development and erosion of the rill.In this paper, the sloping cultivated land which is widely used in the Loess Plateau, such as isobaric seeding, equal height species, manual hoe plowing and high ploughing management measures, is taken as the research object and the leveling slope as the control group.Using X soil from Yang Ling area, different slopes (3 擄5 擄10 擄15 擄and 20 擄), different rainfall intensity of 60 mm / h, 90 mm / h and 120 mm / h) and four different tillage methods (equal height ploughing and manual hoe tillage) were selected.The characteristics of erosion and sediment yield of different surface roughness, the influence of different surface roughness on the formation and development of rill, and the relationship between erosion and erosion of different surface roughness were studied through indoor and outdoor artificial rainfall experiments.The main conclusions are as follows: (1) four different tillage methods produce different surface roughness, and the order of the surface roughness is CK, I. e., the high point planting, the same height tillage, and the same height ploughing.Under the same tillage practices and under the same rainfall intensity, the erosion sediment yield increases with the increase of slope, and decreases with the increase of surface roughness under the same slope and rainfall intensity.However, there is a critical slope in the process of rainfall, which changes the surface roughness from increasing erosion to reducing erosion. This critical slope decreases with the increase of surface roughness.閫氳繃鍗曞洜绱犳柟宸垎鏋愬緱鍑哄潯搴，

本文編號(hào)：1702800