本文選題：石灰土壤 + 土壤CO_2釋放��； 參考：《西北農(nóng)林科技大學(xué)》2017年碩士論文

【摘要】：由于溫室氣體排放的增加,二十世紀(jì)以來全球溫度升高了0.6°C,由此帶來的負(fù)面效應(yīng)正嚴(yán)重威脅著人類的生存與發(fā)展。溫室氣體中CO_2在引發(fā)全球氣候變動(dòng)所占的比例最大,CO_2的權(quán)重約為60%。土壤碳庫(kù)是全球陸地生態(tài)系統(tǒng)的主要碳庫(kù),土壤碳庫(kù)包含有機(jī)和無(wú)機(jī)兩大部分。近年來,我國(guó)農(nóng)業(yè)生產(chǎn)中氮肥用量不斷增加,由于銨態(tài)氮的硝化過程中釋放H+,會(huì)降低土壤pH。施用氮肥對(duì)土壤碳釋放的影響已有不少研究,北方石灰性土壤同時(shí)含有有機(jī)及無(wú)機(jī)碳,施用氮肥導(dǎo)致的土壤p H降低是否會(huì)影響石灰性土壤無(wú)機(jī)碳的釋放,尚少見報(bào)道。硝化抑制劑可以抑制氮素的硝化過程,進(jìn)而減緩?fù)寥纏H的降低幅度。因此,本文采用室內(nèi)培養(yǎng)及田間田間試驗(yàn)方法探究了施用氮肥及與硝化抑制劑配合對(duì)石灰性土壤pH、硝銨態(tài)氮和土壤二氧化碳釋放上碳釋放的影響,旨在評(píng)價(jià)石灰性土壤碳釋放的機(jī)理,為減少CO_2排放和穩(wěn)定土壤碳庫(kù)提供科學(xué)依據(jù)。獲得以下主要結(jié)論:(1)以在西北農(nóng)林科技大學(xué)進(jìn)行了12年的長(zhǎng)期定位常規(guī)模式下不施氮(N0)及施氮量120 kg ha-1(N120)和240 kg ha-1(N240)和3個(gè)處理為研究對(duì)象,連續(xù)兩年(2015及2016)測(cè)定了不同施氮水平下石灰性土壤pH值、礦質(zhì)態(tài)氮含量和CO_2釋放量。連續(xù)兩年的結(jié)果表明:兩年的土壤pH變化趨勢(shì)一致,都呈現(xiàn)先升高后降低的趨勢(shì),土壤pH在施用氮肥處理后顯著降低。施肥處理兩年的土壤銨態(tài)氮含量在兩周內(nèi)都降低到與不施氮無(wú)顯著差異,說明硝化作用在兩周內(nèi)已完成。氮肥施用量越高,土壤CO_2釋放量越高。試驗(yàn)結(jié)束時(shí)與N0處理相比,N120和N240處理的土壤CO_2累積釋放量分別平均增加了30.6%和59.7%,顯著高于N0處理。由于兩年間的溫度與降雨不同,2016年的土壤CO_2累積釋放量稍低于2015年。(2)通過田間試驗(yàn)研究了不同施氮量及與硝化抑制劑(雙氰胺,DCD)配合(N0、N160、N160+DCD、N220和N220+DCD)對(duì)土壤pH值、礦質(zhì)態(tài)氮含量和二氧化碳(CO_2)釋放量的影響。結(jié)果表明,施用氮肥顯著降低了耕層土壤pH,與N0處理相比,N160和N220處理土壤pH平均降低了0.12個(gè)單位;配施DCD后,土壤pH降低幅度小于未加DCD處理。加入DCD使氮肥的硝化過程推遲了約20天時(shí)間。未加入DCD的處理土壤CO_2釋放量隨施氮量增加而增加,試驗(yàn)結(jié)束時(shí)(施肥37 d后)土壤CO_2累積釋放量最高達(dá)到167.1 g m-2;與N0處理相比,N160和N220處理土壤CO_2累積釋放量顯著增加,增幅分別為20.9%和25.7%;N160+DCD和N220+DCD處理顯著降低了土壤CO_2累積釋放量,比對(duì)應(yīng)相同施氮量處理分別降低了13.5%和11.0%。(3)采用密閉培養(yǎng)法研究了施用氮肥及其與硝化抑制劑(DCD)配合對(duì)不同利用方式(農(nóng)田,果園,溫室)石灰性土壤pH、銨態(tài)氮、硝態(tài)氮和CO_2釋放量的影響。結(jié)果表明:與不施肥相比,僅施用氮肥顯著降低了3種土壤的pH值,農(nóng)田、果園和溫室土壤pH在培養(yǎng)期間平均降低了0.44、0.39和0.15個(gè)單位;僅施用氮肥增加了培養(yǎng)期間土壤CO_2釋放量,到培養(yǎng)結(jié)束時(shí)(48 d),農(nóng)田、果園和溫室土壤分別比相應(yīng)不施氮土壤CO_2釋放量平均增加了30.37%、24.49%和25.03%。氮肥配合加入DCD后,土壤銨態(tài)氮的硝化過程的進(jìn)行顯著被抑制,土壤p H的降低幅度明顯低于僅施氮肥處理,農(nóng)田、果園和溫室土壤CO_2平均釋放量較施氮肥分別降低了15%、8.9%和12.6%。
[Abstract]:Because of the increase of greenhouse gas emissions, the global temperature has risen by 0.6 C since twentieth Century, and the negative effects brought by the greenhouse gas are seriously threatening the survival and development of human beings. The proportion of CO_2 in the greenhouse gas is the largest in the global climate change, and the weight of CO_2 is about 60%. soil carbon pool is the main carbon pool of the global terrestrial ecosystem. The soil carbon pool contains two major organic and inorganic parts. In recent years, the amount of nitrogen fertilizer in agricultural production in China has been increasing. Due to the release of H+ in the nitrification process of ammonium nitrogen, there is a lot of research on the effect of nitrogen fertilizer on soil carbon release from soil pH. application. In the northern calcareous soil, there are organic and inorganic carbon, and the application of nitrogen fertilizer to soil P H Reducing the release of inorganic carbon in calcareous soils is rarely reported. Nitrification inhibitors can inhibit nitrification of nitrogen and slow down the reduction of soil pH. Therefore, the application of nitrogen fertilizer and nitrification inhibitor to pH, ammonium nitrate nitrogen, and nitrification inhibitors was investigated in the laboratory and field field experiments. The effect of carbon release from soil carbon dioxide release was aimed at evaluating the mechanism of carbon release from calcareous soil and providing scientific basis for reducing CO_2 emission and stabilizing soil carbon storage. The following main conclusions were obtained: (1) for 12 years in the Northwest Agriculture and Forestry University, nitrogen free (N0) and nitrogen application rate of 120 kg HA-1 (N120) and 2 were carried out at the Northwest Agriculture and Forestry University. 40 kg HA-1 (N240) and 3 treatments were used for two years (2015 and 2016) to determine the pH value, mineral nitrogen and CO_2 release at different levels of nitrogen application. The results of two two years showed that the trend of soil pH changes in two years was the same, and the soil pH was significantly reduced after the application of nitrogen fertilizer treatment. In two weeks, the soil ammonium nitrogen content decreased to no nitrogen application in two weeks, indicating that nitrification was completed within two weeks. The higher the amount of nitrogen fertilizer, the higher the release of soil CO_2. Compared with the N0 treatment, the cumulative release of CO_2 in soil treated by N120 and N240 increased by 30.6% and 59.7%, respectively. The cumulative release of soil CO_2 in 2016 was slightly lower than that in 2015. (2) the soil pH, mineral nitrogen and carbon dioxide (CO_2) release of different nitrogen application and nitrification inhibitors (N0, N160, N160+DCD, N220 and N220+DCD) were studied by field experiments in 2016. (2) the field experiment was conducted to study the amount of nitrogen and the amount of nitrogen application and nitrification inhibitors (DCD, N160, N160+DCD, N220 and N220+DCD). The results showed that the application of nitrogen fertilizer significantly reduced the soil pH in the plough layer. Compared with the N0 treatment, the pH of N160 and N220 treated soil pH decreased by 0.12 units. After the application of DCD, the decrease in soil pH was less than that of the non DCD treatment. The nitrification process of nitrogen fertilizer was delayed about 20 days by adding DCD. The cumulative release of soil CO_2 was up to 167.1 g m-2 at the end of the experiment (after 37 D fertilization). Compared with N0 treatment, the cumulative release of CO_2 in N160 and N220 treatments increased significantly, and the increase was 20.9% and 25.7%, respectively. N160+DCD and N220+DCD treatment significantly reduced the cumulative amount of soil cumulative release, compared with the same nitrogen application amount. The effects of nitrogen fertilizer application and nitrification inhibitor (DCD) on pH, ammonium nitrogen, nitrate nitrogen and CO_2 release of pH, ammonium nitrogen, nitrate nitrogen and CO_2 in different utilization methods (farmland, orchard, greenhouse) were studied by closed culture method. The results showed that the application of nitrogen fertilizer only decreased the pH value of 3 soils compared with no fertilizer. The soil pH in orchard and greenhouse soil decreased by 0.44,0.39 and 0.15 units during the incubation period. Nitrogen fertilizer application only increased the amount of CO_2 release in soil during culture, and at the end of culture (48 d), farmland, orchard and greenhouse soil increased by 30.37%, 24.49% and 25.03%. nitrogen fertilizer, respectively, after adding DCD to DCD. The nitrification process of soil ammonium nitrogen was significantly inhibited, and the decrease of P H in soil was significantly lower than that of nitrogen fertilizer only. The average release of CO_2 in farmland, orchard and greenhouse soil decreased by 15%, 8.9% and 12.6%., respectively.

【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：S143.1

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