發(fā)布時間：2018-05-07 05:30

  本文選題：黃土高原 + 土地利用方式��； 參考：《西北農(nóng)林科技大學》2017年碩士論文

【摘要】：黃土高原占世界黃土總面積的70%,該地區(qū)擁有獨特的氣候特征,植被資源和土壤特性,是我國生態(tài)文明建設(shè)的重點區(qū)域。自國家實施退耕還林的近20年來,黃土高原地區(qū)土地利用類型發(fā)生了重大變化,土地利用變化的同時也改變了土壤水文狀況及土壤碳含量。因此近年來越來越多的研究集中在不同土地利用下土壤水分及碳含量的研究,但這些研究大多集中在表層土壤中,對深層土壤特別是10 m以下的土壤水分和碳分布狀況的研究較少�；诖�,本研究以黃土高原典型丘陵區(qū)的高西溝為主要研究區(qū)域,通過野外采樣和室內(nèi)分析相結(jié)合,研究了該地區(qū)側(cè)柏林、油松林以及蘋果園等不同不同土地利用方式下20 m深土壤剖面的水分、有機碳和無機碳分布特征,并結(jié)合土壤容重、pH、機械組成和根系分布等因素,系統(tǒng)的闡述了土壤水分和土壤碳在不同土地利用方式下的變化特征,得出以下主要結(jié)論:(1)4種類型的機械組成差別較大,其中表層土壤(0~2 m)的砂粒含量大小表現(xiàn)為農(nóng)田蘋果園油松林≈側(cè)柏林,且深層土壤砂粒含量無固定變化趨勢;粉粒含量在表層土壤表現(xiàn)為油松≈側(cè)柏農(nóng)田≈蘋果,隨著深度的增加農(nóng)地粉粒含量逐漸增大,要遠大于其他三種林地;在整個剖面農(nóng)田粘粒含量一直處于較低值,其他三種林地粘粒含量變化較小,其值表現(xiàn)為側(cè)柏蘋果油松農(nóng)田。4種類型的土壤容重均隨土層深度的增加呈增大趨勢,農(nóng)田變化趨勢較大,表層土壤容重較其他三種林地低,隨著深度的增加容重逐漸增大,深層平均土壤容重要大于其他三種林地。土壤pH無明顯的變化規(guī)律,并且農(nóng)田和林地無明顯差異。(2)對農(nóng)田和側(cè)柏林、油松林和蘋果園進行土壤水分特征分析發(fā)現(xiàn),在20 m土層范圍內(nèi)土壤平均含水率為農(nóng)田蘋果園≈油松林≈側(cè)柏林,其值分別為11.30%、6.66%、6.48%和5.92%。農(nóng)田土壤含水率呈先減小后增大的趨勢,隨著深度的增加變化趨勢并不明顯,三種林地在表層含水量極速降低,在1~10 m深處于整個剖面的較低水平,10 m之后土壤含水率隨著深度的增加逐漸增大,但其變化趨勢并不明顯,三種林地之間也無較顯著差別。(3)本研究分析了不同土地利用方式下SOC變化規(guī)律,得出SOC含量均隨深度的增加逐漸降低,表層土壤SOC變化較大,隨著深度的增加變化逐漸減小;林地SOC的含量要遠高于農(nóng)田,林地整個20 m剖面的SOC儲量約為農(nóng)地的1.74倍。SIC含量的變化趨勢與有機碳相反,即隨土層深度的增加SIC呈上升趨勢,但變化較緩慢,林地SIC含量與農(nóng)田差異較小,但總體表現(xiàn)為林地農(nóng)田;整個20 m深剖面的農(nóng)地平均SIC含量為11.24 g·kg-1,約為林地(12.98 g·kg-1)SIC含量的86.6%。
[Abstract]:Loess Plateau accounts for 70% of the total loess area in the world. It has unique climatic characteristics, vegetation resources and soil characteristics, which is the key area of ecological civilization construction in China. In the past 20 years, the types of land use in the Loess Plateau have changed greatly, and the change of land use has also changed the soil hydrology and soil carbon content. Therefore, in recent years, more and more studies have focused on soil moisture and carbon content under different land use, but most of these studies are concentrated in the surface soil. The distribution of soil moisture and carbon in deep soil, especially under 10 m, was less studied. Based on this, this study took the high west gully of the typical hilly area of the Loess Plateau as the main research area, and studied the Platycladus orientalis forest in this area through the combination of field sampling and indoor analysis. The distribution characteristics of soil moisture, organic carbon and inorganic carbon in 20m deep soil profile under different land use patterns, such as Pinus tabulaeformis forest and apple orchard, combined with soil bulk density pH, mechanical composition and root distribution, etc. The variation characteristics of soil moisture and soil carbon under different land use patterns are systematically expounded. The following main conclusions are drawn that there are great differences in mechanical composition of four types of soil moisture and soil carbon. Among them, the sand content of surface soil was about Pinus tabulaeformis forest, and the sand content of deep soil had no fixed change trend, and the silt content in surface soil was that Pinus tabulaeformis 鈮，

本文編號：1855594