本文關(guān)鍵詞： 氮沉降 克氏針茅草原 土壤呼吸 太仆寺旗　出處：《內(nèi)蒙古師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,由于內(nèi)蒙古地區(qū)采礦業(yè)及發(fā)電業(yè)迅速發(fā)展,氮沉降量逐年增多。為研究氮沉降對(duì)內(nèi)蒙古克氏針茅(Stipa krylovii)草原土壤呼吸的影響,于2014年7月開始在內(nèi)蒙古太仆寺旗的克氏針茅草原開展了模擬氮沉降的控制實(shí)驗(yàn),設(shè)置對(duì)照(N0)和5個(gè)模擬氮沉降(NO3-)處理,分別為2 g N m-2·yr-1(N1)、5 g N m-2·yr-1(N2)、10 g N m-2·yr-1(N3)、25 g N m-2·yr-1(N4)和50 g N m-2·yr-1(N5)監(jiān)測(cè)不同氮沉降處理下土壤呼吸季節(jié)變化和日動(dòng)態(tài)變化,并結(jié)合土壤表層水熱條件分析該地區(qū)的土壤呼吸特性,探討不同施氮水平對(duì)草地CO2排放的影響,為未來全球變化下的天然草地保護(hù)與管理提供科學(xué)依據(jù)和理論支撐。主要結(jié)論如下:(1)各處理下的土壤呼吸速率為夏季秋季冬季。重復(fù)測(cè)量方差結(jié)果表明,與對(duì)照組比,施氮改變了土壤呼吸日均和白天的季節(jié)動(dòng)態(tài)變化。而各施氮水平下的黑夜土壤呼吸季節(jié)動(dòng)態(tài)變化與對(duì)照組的無差異�？耸厢樏┎菰瓡円雇寥篮粑俾首畲笾�2.45±0.36μmol·m-2·s-1出現(xiàn)在7月份,最小值0.11±0.01μmol·m-2·s-1出現(xiàn)在11月。(2)7月和9月不同施氮水平之間的日均、白天、黑夜土壤呼吸的整體趨勢(shì)為隨著施氮量的增加,土壤呼吸減弱,即施氮抑制了土壤呼吸。11月的晝夜和白天土壤呼吸則無顯著變化,而11月黑夜的土壤呼吸隨著施氮量的增加逐漸增長(zhǎng),施氮促進(jìn)了黑夜的土壤呼吸。從土壤呼吸日變化曲線圖可得知,施氮沒有改變土壤呼吸日變化規(guī)律。(3)采用線性回歸模型得出,土壤溫度、濕度、施氮、地下生物量和C/N共同解釋了克氏針茅草原土壤呼吸速率季節(jié)變化的74.7%,擬合結(jié)果優(yōu)于以溫度為參數(shù)的線性回歸模型(72.2%)。而土壤濕度、地下生物量以及施氮與土壤呼吸相關(guān)性不顯著。影響土壤呼吸速率的主導(dǎo)因子是溫度,土壤呼吸與土壤溫度之間存在極顯著的指數(shù)關(guān)系。雖然以相關(guān)性分析法得出的結(jié)論為施氮并未改變土壤呼吸溫度敏感性,但對(duì)比同一月份的不同水平下的Q10值,受施氮影響Q10逐漸降低。(4)適量的氮素會(huì)增加地下生物量,而高氮?jiǎng)t抑制其生長(zhǎng)。國(guó)家自然科學(xué)基金資助項(xiàng)目(41371069)(5)土壤C/N比隨著施氮量的增加而變化。與對(duì)照組相比,各土層土壤C/N比隨著施氮量的增加而增加。而施氮量達(dá)到N3水平時(shí)土壤碳氮比隨著施氮量的增加而逐漸下降。本研究中,施氮抑制了土壤呼吸:低氮增加了地下生物量和C/N。高氮減少了地下生物量,降低了土壤C/N。從觀測(cè)結(jié)果來看,同一水平的施氮量對(duì)土壤根系呼吸和土壤微生物呼吸具有不同的影響。
[Abstract]:In recent years, because of the rapid development of mining industry and power generation industry in Inner Mongolia, the amount of nitrogen deposition increased year by year. In order to study the effect of nitrogen deposition on soil respiration of Stipa krylovii steppe in Inner Mongolia, In July 2014, the control experiment of simulated nitrogen deposition was carried out in the Plantago krshinshinensis in Taibusi Banner, Inner Mongolia, with the control of N _ 0) and five simulated nitrogen deposition no _ 3) treatments. The seasonal and diurnal changes of soil respiration under different nitrogen deposition treatments were monitored, and the soil respiration characteristics in this area were analyzed by means of 10 g N m-2 路yr-1 N _ 2 路yr ~ (-1) N _ (2) N _ (m ~ (-2) 路yr ~ (-1) N ~ (-1)) and 50 g N ~ (m ~ (-2) 路yr-1 ~ (-1) N _ (5)) respectively. The effects of different nitrogen levels on CO2 emission from grassland were studied. The main conclusions are as follows: the soil respiration rate of each treatment is summer, autumn and winter. The results of repeated measurement variance show that, compared with the control group, the soil respiration rate of each treatment is in summer, autumn and winter. The daily and daytime seasonal dynamic changes of soil respiration were changed by nitrogen application, but there was no difference between the night soil respiration season and the control group. The maximum diurnal soil respiration rate appeared in July, and the maximum soil respiration rate was 2.45 鹵0.36 渭 mol 路m ~ (-2) 路s ~ (-1) on July. The minimum value of 0. 11 鹵0. 01 渭 mol 路m -2 路s -1 appeared in November. Soil respiration was inhibited by nitrogen application, but no significant change was observed during the day and night of November, but the soil respiration increased gradually with the increase of nitrogen application rate in November. From the curve of diurnal variation of soil respiration, nitrogen application did not change the diurnal variation of soil respiration. The below-ground biomass and C / N explained the seasonal variation of soil respiration rate of Neymphus krjabini. The fitting results were better than that of the linear regression model with temperature as the parameter (72.2%), and the soil moisture was higher than that of the linear regression model (72.2%). There was no significant correlation between underground biomass and nitrogen application and soil respiration. Temperature was the main factor affecting soil respiration rate. There was a significant exponential relationship between soil respiration and soil temperature. Although the conclusion of correlation analysis was that nitrogen application did not change the sensitivity of soil respiration temperature, the Q10 values at different levels were compared with those of January. The effect of nitrogen application on Q10 decreased gradually. (4) proper amount of nitrogen increased the underground biomass, but high nitrogen inhibited the growth. The C / N ratio of soil changed with the increase of N application rate, compared with the control group, supported by the National Natural Science Foundation of China (NSF-funded project No. 41371069). The C / N ratio of different soil layers increased with the increase of N application rate, and the C / N ratio decreased with the increase of N application rate when the N application rate reached N 3 level. Nitrogen application inhibited soil respiration: low nitrogen increased underground biomass and C / N. High nitrogen reduced underground biomass, decreased soil C / N. Nitrogen application at the same level had different effects on soil root respiration and soil microbial respiration.
【學(xué)位授予單位】：內(nèi)蒙古師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S812.2

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