本文選題：微區(qū) + 土壤水分　； 參考：《甘肅農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：選擇甘肅民勤綠洲荒漠過(guò)渡帶廣泛分布的微區(qū)(白刺沙堆丘間低地微區(qū)、粘土沙障+梭梭固沙林內(nèi)微區(qū)及粘土平地微區(qū))作為研究對(duì)象,通過(guò)查閱降水資料、野外調(diào)查、土樣采集、人工模擬降雨及跟蹤觀(guān)測(cè)土壤含水量,研究微區(qū)土壤入滲過(guò)程及水分時(shí)空動(dòng)態(tài)變化,結(jié)果表明:(1)研究區(qū)降水量在年際間差異較小且服從正態(tài)分布。降水主要集中于7~9月,多年月均降水量變幅大,四季降水分布差異大。降水多發(fā)生于夜間,不考慮月份變化,晝夜間降水量相關(guān)性顯著且呈正比。大雨量級(jí)相比小雨量級(jí)其降水次數(shù)年際差異大,降水次數(shù)隨雨量級(jí)數(shù)增大而減小。(2)微區(qū)徑流特點(diǎn):匯離短、匯流面小、流量小;產(chǎn)生形式:坡面徑流、樹(shù)干徑流;產(chǎn)流過(guò)程:蓄滲階段、坡面漫流階段。三種類(lèi)型微區(qū)積水區(qū)與產(chǎn)流區(qū)土壤粒度:白刺沙堆丘間低地細(xì)砂粒含量在積水區(qū)和產(chǎn)流區(qū)各層中所占比例最大,0~10 cm土壤表層積水區(qū)粘、粉粒含量遠(yuǎn)小于產(chǎn)流區(qū)。粘土平地積水及產(chǎn)流區(qū)土壤組成以粗、細(xì)砂粒為主,粘粒含量在各對(duì)應(yīng)層產(chǎn)流區(qū)都好于積水區(qū)。粘土沙障+梭梭固沙林以粗砂粒為主,結(jié)構(gòu)較為單一。(3)粘土沙障+梭梭固沙林和白刺沙堆丘間低地微區(qū)雨強(qiáng)與徑流量關(guān)系呈一定的線(xiàn)性關(guān)系。(4)27.4 mm降雨結(jié)束后,粘土沙障+梭梭固沙林內(nèi)微區(qū)核心、過(guò)渡和邊緣區(qū)土壤水分在0~14 h入滲較快;14~86 h明顯下降;86 h后入滲很少。白刺沙堆丘間低地微區(qū)0~14 h入滲較快(過(guò)渡區(qū)邊緣區(qū)核心區(qū)),但遠(yuǎn)小于粘土沙障+梭梭固沙林三區(qū)結(jié)果;14~74 h,下滲速率變緩;74~254 h,三區(qū)下滲依舊持續(xù);至254h其入滲深度小于粘土沙障+梭梭固沙林內(nèi)三區(qū)所得結(jié)果。(5)降水結(jié)束后三區(qū)0~20 cm層土壤水分:粘土沙障+梭梭固沙林0~8 h內(nèi)損失(核心區(qū)過(guò)渡區(qū)產(chǎn)流區(qū))較小;8~86 h損失較大;86~254 h,三區(qū)該層土壤水分損失速率變緩。白刺沙堆丘間低地0~14 h損失速率(核心區(qū)邊緣區(qū)過(guò)渡區(qū))較小;14~74 h損失過(guò)程與粘土沙障+梭梭固沙林8~86 h結(jié)果相似,土壤水分散失明顯(核心區(qū)邊緣區(qū)過(guò)渡區(qū));74~254 h散失依舊持續(xù),速率變緩,土壤最終含水量:核心區(qū)邊緣區(qū)過(guò)渡區(qū)。(6)兩類(lèi)微區(qū)(粘土沙障+梭梭固沙林和白刺沙堆丘間低地)所設(shè)置不同降雨梯度微型蒸滲儀中一天的水分散失過(guò)程基本相似。兩類(lèi)微區(qū)三區(qū)水分蒸發(fā)過(guò)程具有相似性,散失量:邊緣區(qū)過(guò)渡區(qū)核心區(qū)。兩類(lèi)型微區(qū)在整個(gè)實(shí)驗(yàn)過(guò)程中每天蒸發(fā):15 mm降水量對(duì)應(yīng)蒸發(fā)量10 mm降水量對(duì)應(yīng)蒸發(fā)量5 mm降水量對(duì)應(yīng)蒸發(fā)量。(7)27.4 mm降雨前期兩類(lèi)型微區(qū)三區(qū)在0~140 cm垂直剖面上土壤水分呈下高上低梯度分布。粘土沙障+梭梭固沙林內(nèi)微區(qū)最大入滲深度:核心區(qū)80 cm,過(guò)渡及邊緣區(qū)為60 cm;白刺沙堆丘間低地:核心區(qū)40 cm,過(guò)渡、邊緣區(qū)為60 cm。粘土沙障+梭梭固沙林內(nèi)微區(qū)三區(qū)土壤水分動(dòng)態(tài)分三層次:低值層,都在20 cm左右;次活躍層,核心區(qū)20~80 cm,過(guò)渡及邊緣區(qū)20~60 cm;穩(wěn)定層,核心區(qū)80~140 cm,過(guò)渡及邊緣區(qū)60~140 cm。白刺沙堆丘間低地:低值層,核心區(qū)0~15 cm、過(guò)渡區(qū)0~20 cm、邊緣區(qū)0~20 cm;水分活躍層,核心區(qū)15~30 cm、過(guò)渡區(qū)20~40 cm、邊緣區(qū)為20~60 cm;土壤水分穩(wěn)定層:核心區(qū)30~140 cm、過(guò)渡區(qū)40~140 cm、邊緣區(qū)60~140 cm。(8)三種類(lèi)型微區(qū)不同區(qū)域內(nèi)植物群落組成結(jié)構(gòu)簡(jiǎn)單,種類(lèi)少。白刺沙堆丘間低地及粘土沙障+梭梭固沙林微區(qū)內(nèi)建群植被逐漸退化,以黃花磯松和紅砂為主的淺根性灌木和以畫(huà)眉草、虎尾草和五星蒿為主的草本植被的進(jìn)入,原有植被群落最終演替方向:喬木-喬灌草-灌草。
[Abstract]:The microarea widely distributed in the desert transition zone of Minqin oasis, Gansu, is selected as the research object. As the research object, the clay sand barrier + Haloxylon ammodendron sand fixation forest micro area and the clay flat micro area are used as the research object. By consulting the precipitation data, field investigation, soil sample collection, artificial rainfall and tracking the soil moisture content, the infiltration of soil in the micro area is studied. The results show that: (1) the precipitation in the study area is smaller and obeys the normal distribution in the interannual. The precipitation is mainly concentrated in 7~9 months, the average precipitation varies greatly in the year and month, the distribution of precipitation in the four seasons is large. The precipitation occurs at night and does not consider the change of month. The correlation of day and night precipitation is significant and positive ratio. The precipitation times are different with the magnitude of precipitation, and the number of precipitation decreases with the increase of rainfall series. (2) the characteristics of micro runoff: short sink, small confluence surface and small flow; production form: slope runoff, trunk runoff; flow process: infiltration stage, sloping flow stage. Soil granularity in three types of micro area water area and runoff region: white thorn sand The proportion of the low ground fine sand particles in the lower hilly area is the largest in the accumulated water area and each layer of the runoff producing area, and the 0~10 cm soil surface water area is sticky and the powder content is far smaller than that in the runoff producing area. The sand grain is the main structure. (3) there is a linear relationship between the rain strength of the clay sand barrier + Haloxylon ammodendron sand forest and the white thorn sand pile. (4) after the 27.4 mm rainfall, the clay sand barrier + Haloxylon ammodendron sand fixation forest is the core, the soil moisture in the transition and marginal areas is rapidly infiltrated in the 0~14 h, and the 14~86 h decreases obviously; 86 h after the entry. The infiltration of 0~14 h in the lowland micro area of the white thorn sand pile is faster (the core area of the transition zone), but it is far less than the three zone of clay sand barrier + Haloxylon ammodendron sand forest; 14~74 h, the infiltration rate slows down; 74~254 h, the infiltration of the three region remains continuous; to 254h, the infiltration depth is less than the three regions in the clay sand barrier + Haloxylon ammodendron sand fixation forest. (5) after precipitation over the end of precipitation. Soil moisture in the three 0~20 cm layer: clay sand barrier + Haloxylon ammodendron sand fixation forest 0~8 h loss (the transition zone of core region) is smaller; 8~86 h loss is larger; 86~254 h, the three zone soil moisture loss rate slows. The low 0~14 h loss rate (the transition zone in the core region of the core region) is smaller, 14~74 h loss process and clay sand barrier + Haloxylon ammodendron. The results of 8~86 h in sand fixation forest are similar, the soil moisture loss is obvious (the transition zone in the periphery of the core region); the 74~254 h dispersion continues, the rate is slow, the final soil moisture content is the transition zone in the marginal zone of the core area. (6) one day in the two kind of micro area (clay sand barrier + Haloxylon ammodendron sand forest and white thorn sand pile low land) The water evaporation process is similar. The evaporation process of water evaporation in the two kind of micro area three regions is similar, and the loss amount: the core area of the transition zone in the marginal zone. The two types of microregions evaporate in the whole experiment process, 15 mm precipitation corresponds to 10 mm of evaporation and 5 mm of evaporation to the evapotranspiration. (7) two types of 27.4 mm in the early period of rainfall. The soil moisture in the three area on the vertical section of the 0~140 cm is lower and lower gradient. The maximum infiltration depth in the clay sand barrier + Haloxylon ammodendron sand fixation forest: the core area is 80 cm, the transition and the marginal zone is 60 cm; the white thorn sand pile is low in the hilly area: the core area is 40 cm, the transition is the 60 cm. clay sand barrier + Haloxylon ammodendron sand fixation forest soil moisture dynamic score in the three region. The three level: the low value layer is around 20 cm; the secondary active layer, the core area 20~80 cm, the transition and the marginal zone 20~60 cm; the stable layer, the core region 80~140 cm, the transition and the marginal zone 60~140 cm. white thorns dune lowland: the low value layer, the 0~15 cm in the core region, the transitional zone 0~20, the marginal zone, the core region, the transition zone, the edge The area is 20~60 cm, and the soil water stable layer: the core region 30~140 cm, the transition zone 40~140 cm, the marginal region 60~140 cm. (8), the plant community structure is simple and the species are few in the three types of micro regions. Herbaceous vegetation dominated by sexual shrubs and turtgrass, tiger tail and Artemisia Artemisia, and the final succession direction of the original vegetation communities: arbor, shrub, grass and shrub.
【學(xué)位授予單位】：甘肅農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：S152.7

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