發(fā)布時(shí)間：2018-03-11 00:21

  本文選題：退化草原　切入點(diǎn)：土壤有機(jī)質(zhì)　出處：《內(nèi)蒙古大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：本研究選取錫林郭勒盟白音牧場(chǎng)輕度退化和重度退化典型草原群落,分別進(jìn)行了氮素添加梯度(0、30、50、80 g/m2 NH4N03)實(shí)驗(yàn)和去除功能群(將植物按能量功能群分類(lèi)：高能值植物、中能值植物和低能值植物功能群,每個(gè)處理剪除另外兩個(gè)功能群,分別保留高、中、低單一功能群)實(shí)驗(yàn),研究不同土層(0-10cm,10-20cm, 20-30cm)土壤有機(jī)質(zhì)含量在不同退化狀況下對(duì)氮素添加及功能群去除的響應(yīng)。主要結(jié)論如下：(1)兩種不同退化程度草原群落比較,輕度退化草原的0-20cm層土壤有機(jī)質(zhì)含量顯著高于重度退化草原,20-30cm層二者無(wú)顯著差異,氮素的添加并沒(méi)有顯著改變這種格局。(2)不同退化程度草原對(duì)于氮素添加梯度的響應(yīng)不同：對(duì)于輕度退化草原,30g/m2氮素添加顯著提高0-20cm土層的土壤有機(jī)質(zhì)含量,氮素是輕度退化草原主要的限制因子；對(duì)于重度退化草原,土壤有機(jī)質(zhì)在氮素添加梯度下各層變化不顯著,氮素不是重度退化草原的主要限制因子。(3)草原土壤有機(jī)質(zhì)隨著土層深度的下降而顯著下降,隨著退化程度的加劇而顯著下降。功能群去除會(huì)顯著增加土壤有機(jī)質(zhì)的含量。在影響草原土壤有機(jī)質(zhì)含量的主效應(yīng)因素中,作用大小依次為：土壤深度退化程度功能群去除(4)在兩種不同退化程度的草原,植物能量功能群的去除能明顯提高土壤有機(jī)質(zhì)含量,在輕度退化樣地,保留單一低能值和高能值功能群對(duì)土壤有機(jī)質(zhì)的影響顯著,但三種去除處理(即分別保留高能群、中能群和低能群)之間無(wú)顯著性差異；在重度退化樣地,保留單一高能值功能群對(duì)土壤有機(jī)質(zhì)的影響顯著,除在20-30cm高能值和低能值功能群土壤有機(jī)質(zhì)含量有顯著差異,其他功能群去除處理之間無(wú)顯著性差異。
[Abstract]:In this study, the typical grassland communities with slight degradation and severe degradation were selected from Baiyin pasture of Xilingol League. The experiments of nitrogen supplementation were carried out and the removal of functional groups (classification of plants according to energy functional groups: high energy plants) and removal of functional groups (NH4N03) were carried out respectively. Middle and low energy plant functional groups, each processing cutting off the other two functional groups, respectively, high, middle, low single functional groups) experiment, The responses of soil organic matter contents in different soil layers to nitrogen addition and functional group removal under different degradation conditions were studied. The main conclusions were as follows: 1) the comparison of two grassland communities with different degradation degree, the soil organic matter content in different soil layers was 10 ~ (-20) cm ~ (-1) and 20 ~ (30 cm) soil organic matter content in different degradation conditions. There was no significant difference in soil organic matter content between 0 ~ 20cm layer and 20 ~ 30cm layer of severe degraded grassland, and there was no significant difference between them. Nitrogen addition did not significantly change the pattern. (2) the response of grassland with different degradation degree to nitrogen gradient was different: for mild degraded grassland, nitrogen addition of 30 g / m 2 significantly increased soil organic matter content in 0-20 cm soil layer. Nitrogen is the main limiting factor of the degraded grassland, but for the heavily degraded grassland, the soil organic matter has no significant change under the nitrogen gradient. Nitrogen is not the main limiting factor of heavily degraded steppe.) soil organic matter in steppe decreased significantly with the decrease of soil depth. The removal of functional groups can significantly increase the content of soil organic matter. Among the main effect factors affecting the content of soil organic matter in steppe soil, The order of action was as follows: soil depth degradation degree functional group removal 4) in two different degraded steppe, the removal of plant energy function group could obviously improve soil organic matter content, in the slightly degraded sample land, The effects of single low energy and high energy functional groups on soil organic matter were significant, but there was no significant difference among the three removal treatments (i.e., retention of high energy group, middle energy group and low energy group). Retention of a single high-energy functional group had a significant effect on soil organic matter, except for 20-30cm high energy value and low-energy functional group soil organic matter content, but no significant difference between other functional groups removal treatment.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：S812.2

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本文編號(hào)：1595754