發(fā)布時(shí)間：2018-07-12 13:51

  本文選題：增氮 + 增雨��； 參考：《東北師范大學(xué)》2015年碩士論文

【摘要】：大氣氮沉降加劇與降水格局改變是全球變化的重要表象。水分與氮素均為溫帶半干旱區(qū)草原生態(tài)系統(tǒng)初級生產(chǎn)力的限制性因素。氮素增加與降水改變直接或間接地影響草地生態(tài)系統(tǒng)的氮循環(huán)速率。本文以內(nèi)蒙古貝加爾針茅草甸草原為研究對象,實(shí)施增氮、增雨處理。增氮通過施用硝酸銨和尿素(分別占總施氮量的70%和30%)來實(shí)現(xiàn),施氮量分為高(12 g N m-2 a-1)、中(6 g N m-2 a-1)、低(0 g N m-2 a-1,即自然肥力)三個(gè)水平;增雨通過集水槽截流降雨澆灌法來實(shí)現(xiàn),增雨量分為高(增加2/7自然降水)、中(增加1/7自然降水)、低(自然降水)三個(gè)水平;增氮、增雨及二者互作一共九種處理組合,每一種處理四個(gè)重復(fù),采用PVC頂蓋埋管培養(yǎng)技術(shù)來測取土壤氮礦化速率,研究增氮、增雨及二者互作對草地土壤無機(jī)氮含量、土壤氮礦化速率以及土壤理化性質(zhì)的影響。主要結(jié)論如下:(1)總體來看,在6-8月期間,土壤銨態(tài)氮含量的增加幅度明顯高于硝態(tài)氮含量的增加幅度。從銨態(tài)氮含量來看,高氮(N2)條件下土壤8月份的銨態(tài)氮含量隨著水分增加顯著升高,而高水(W2)條件下土壤8月份的銨態(tài)氮含量也呈現(xiàn)隨著氮素水平增加而顯著升高的趨勢�？梢�,增氮、增雨處理在提高土壤銨態(tài)氮含量過程中存在相互促進(jìn)的交互效應(yīng)。從硝態(tài)氮含量來看,增氮、增雨處理無交互效應(yīng)。增氮處理對于硝態(tài)氮含量的影響作用較大,而增雨處理對于土壤硝態(tài)氮含量幾乎無影響。(2)增氮、增雨以及二者交互效應(yīng)在6月10日-7月10日、7月10日-8月10日間隔內(nèi)對土壤凈銨化速率及凈硝化速率均不顯著。然而,增雨處理對于6月10日-8月10日兩個(gè)月間隔的土壤凈銨化速率具有顯著影響作用。同樣,增氮處理對于6月10日-8月10日間隔的土壤凈硝化速率的影響達(dá)到顯著水平�？梢�,增氮、增雨處理對草地生態(tài)系統(tǒng)土壤氮礦化過程的影響具有時(shí)間上的累加效應(yīng)。(3)水分是影響土壤銨態(tài)氮和土壤凈銨化速率的主要因子,而氮素水平對土壤硝態(tài)氮和土壤凈硝化速率影響作用顯著。由于土壤硝態(tài)氮含量遠(yuǎn)遠(yuǎn)高于銨態(tài)氮含量,因此,氮素水平對于土壤總無機(jī)態(tài)氮含量及礦化過程一定程度上掩蓋了水分因子的作用效果。綜上,不同梯度的增氮和增雨對于貝加爾針茅草甸草原土壤氮礦化過程及土壤氮素含量均具有明顯的影響。然而,增氮、增水處理對于土壤銨態(tài)氮和硝態(tài)氮作用效果不同。增氮會更多地影響土壤硝態(tài)氮含量與凈硝化速率,進(jìn)而影響土壤無機(jī)態(tài)氮含量及氮礦化�？傮w上,大氣氮沉降及降水格局改變背景下草地?zé)o機(jī)氮及凈氮礦化速率的變化可能是枯落物、植物、土壤環(huán)境及其土壤微生物等多因素相互作用的結(jié)果。
[Abstract]:The increase of atmospheric nitrogen deposition and the change of precipitation pattern are important phenomena of global change. Water and nitrogen were restrictive factors of primary productivity of grassland ecosystem in temperate semiarid region. Nitrogen increase and precipitation change directly or indirectly affect the nitrogen cycling rate of grassland ecosystem. In this paper, Nei Mongol Bekal Stipa meadow grassland as the research object, nitrogen and rain treatment. The nitrogen increase was achieved by applying ammonium nitrate and urea (70% and 30% of the total nitrogen fertilizer, respectively). The nitrogen application amount was divided into three levels: high (12 g N m-2 a-1), middle (6 g N m-2 a-1) and low (0 g N m-2 a-1, I. E. natural fertility). The precipitation increase is divided into three levels: high (increase 2 / 7 of natural precipitation), middle (increase 1 / 7 of natural precipitation), and low (natural precipitation). The rate of nitrogen mineralization in soil was measured by PVC capping tube culture technique. The effects of nitrogen enrichment, precipitation and interaction on the content of inorganic nitrogen, mineralization rate of soil nitrogen and physical and chemical properties of soil were studied. The main conclusions are as follows: (1) in the period of June to August, the increase of soil ammonium nitrogen content was obviously higher than that of nitrate nitrogen content. According to the content of ammonium nitrogen, the content of ammonium nitrogen in August increased significantly with the increase of water content under the condition of high nitrogen (N2), and the content of ammonium nitrogen in August increased with the increase of nitrogen level in high water (W2). It can be seen that there is a mutually reinforcing interaction effect in the process of increasing the content of ammonium nitrogen in soil under the treatment of increasing nitrogen and rain. From the point of view of nitrate nitrogen content, no interaction effect was found between nitrogen increasing and precipitation increasing. The effect of nitrogen treatment on nitrate content was greater than that of rain treatment. (2) nitrogen increasing treatment had little effect on nitrate nitrogen content in soil. (2) nitrogen increasing treatment had little effect on soil nitrate nitrogen content. During the interval of June 10 to July 10, July 10 to August 10, the rate of net ammonium and nitrification of soil were not significant. However, the precipitation treatment had a significant effect on the net ammonium rate of soil between June 10 and August 10. Similarly, the effect of nitrogen addition on the net nitrification rate between June 10 and August 10 was significant. It can be seen that the effects of nitrogen and rain treatment on soil nitrogen mineralization in grassland ecosystem have a cumulative effect on time. (3) Water is the main factor affecting soil ammonium nitrogen and soil net ammonium mineralization rate. The effect of nitrogen level on soil nitrate nitrogen and net nitrification rate was significant. Because the content of soil nitrate nitrogen is much higher than that of ammonium nitrogen, the effect of nitrogen level on the content of total inorganic nitrogen and mineralization process of soil is masked to some extent. In conclusion, the nitrogen mineralization process and soil nitrogen content in the steppe of Stipa baicalensis meadow were significantly affected by nitrogen increasing and rain increasing with different gradients. However, the effects of nitrogen and water treatment on soil ammonium and nitrate were different. The increase of nitrogen will affect the nitrate content and the net nitrification rate, and then affect the inorganic nitrogen content and nitrogen mineralization in the soil. In general, the change of mineralization rate of inorganic nitrogen and net nitrogen in grassland under the background of atmospheric nitrogen deposition and precipitation pattern change may be the result of the interaction of litter, plant, soil environment and soil microorganism.
【學(xué)位授予單位】：東北師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S812.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 徐敏;羅勇;徐影;郭品文;徐經(jīng)緯;;溫室氣體穩(wěn)定濃度情景下中國地區(qū)溫度和降水變化[J];氣候變化研究進(jìn)展;2009年02期

2 高旭升;田種存;郝學(xué)寧;蔣桂香;;三江源區(qū)高寒草原草地不同退化程度土壤養(yǎng)分變化[J];青海大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年05期

3 林啟美,吳玉光,劉煥龍;熏蒸法測定土壤微生物量碳的改進(jìn)[J];生態(tài)學(xué)雜志;1999年02期

4 李香蘭,劉玉民;西北黃土地區(qū)土壤腐殖物質(zhì)的研究[J];土壤學(xué)報(bào);1989年03期

5 李東坡,陳利軍,武志杰,朱平,任軍,梁成華,彭暢,高紅軍;不同施肥黑土微生物量氮變化特征及相關(guān)因素[J];應(yīng)用生態(tài)學(xué)報(bào);2004年10期

6 劉淼;梁正偉;;草地生態(tài)系統(tǒng)氮循環(huán)研究進(jìn)展[J];中國草地學(xué)報(bào);2010年05期

7 曾德慧,陳廣生;生態(tài)化學(xué)計(jì)量學(xué):復(fù)雜生命系統(tǒng)奧秘的探索[J];植物生態(tài)學(xué)報(bào);2005年06期

相關(guān)博士學(xué)位論文 前1條

1 張麗霞;植物N：P計(jì)量化學(xué)：中國高等植物的分異規(guī)律與野外實(shí)驗(yàn)初步驗(yàn)證[D];中國科學(xué)院研究生院（植物研究所）;2003年

相關(guān)碩士學(xué)位論文 前1條

1 張光波;草地不同植物多樣性背景下放牧對植物和土壤生態(tài)化學(xué)計(jì)量學(xué)特征的影響[D];東北師范大學(xué);2011年

，

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