本文選題：地膜覆蓋 + 水稻-油菜輪作農田��； 參考：《西南大學》2017年碩士論文

【摘要】：近幾十年來,大氣中溫室氣體濃度不斷增加,隨之加強的溫室效應已經(jīng)成為一個全球性的環(huán)境問題,除了化學燃料燃燒外,農業(yè)是人類活動所產(chǎn)生的溫室氣體的重要源。地膜覆蓋技術的使用是我國農業(yè)生產(chǎn)的一次“白色革命”,自上世紀70年代引進地膜覆蓋技術以來,該技術在我國已得到廣泛的推廣運用。地膜覆蓋后,地膜與土壤之間設置了一道物理阻隔,直接阻擋了水分的垂直蒸發(fā),阻斷了近地面層與大氣之間的氣流交換,增大了光熱交換阻力,使膜內土壤溫、光、水、肥、氣等生態(tài)條件都發(fā)生了變化。地膜覆蓋后對農田生態(tài)系統(tǒng)溫室氣體的排放以及碳的固定產(chǎn)生怎樣的影響?在全球氣候日趨暖化的背景下,這些都是需要迫切解決的科學問題。本研究選取西南地區(qū)普遍的水稻-油菜輪作農田為研究對象,在重慶市西南大學紫色土生態(tài)環(huán)境重點野外科學觀測試驗站,開展了地膜覆蓋對農田主要溫室氣體(CH_4、N_2O和CO_2)排放的規(guī)律及其影響因素的研究。目前,對地膜覆蓋水稻-油菜輪作種植農田溫室氣體排放的研究相對較少,并且考慮農田環(huán)境因素的復雜多變,因此,在已完成的第一年實驗的基礎上(2014年05月至2015年04月),繼續(xù)增加了第二年的田間觀測實驗(2015年05月至2016年04月)。期望通過水稻-油菜輪作農田兩年的田間觀測結果的比較,從年際的角度更全面地了解地膜覆蓋農田溫室氣體排放的規(guī)律及其影響因素。研究取得的主要結果如下:1.地膜覆蓋對水稻-油菜輪作農田CH_4、N_2O排放的影響(1)在水稻-油菜輪作農田中,CH_4排放通量與溫度呈顯著正相關關系,CH_4的排放集中出現(xiàn)在水稻和油菜種植期間,且排放峰值并分別出現(xiàn)在水稻種植的中后期和油菜種植的前期,通過兩年的實驗發(fā)現(xiàn),地膜覆蓋可增加農田CH_4的排放,第一年和第二年覆膜排放量增加44%和110%。(2)在水稻-油菜輪作農田中,N_2O排放受溫度影響小(n=47,P0.05),N_2O的大量排放往往與農田的施肥和土壤干濕交替有關,N_2O排放集中出現(xiàn)在農田施肥之后,油菜種植期間釋放量占農田N_2O釋放的大部分(90%以上)。地膜對農田N_2O排放的影響比較復雜:在多雨濕潤的冬季覆蓋地膜農田N_2O的排放量減少27%(第二年),而在少雨干燥的冬季覆蓋地膜農田N_2O的排放量增加33%(第一年)。(3)在水稻-油菜輪作農田中,通過兩年的實驗發(fā)現(xiàn):在水稻生長期間,農田中CH_4、N_2O兩種溫室氣體的排放特征表現(xiàn)為“此消彼長”,并且在高溫少雨的春季農田CH_4、N_2O兩種氣體的排放出峰時間差將增加。而在油菜生長期間,農田中CH_4、N_2O兩種溫室氣體排放沒有出現(xiàn)“此消彼長”的現(xiàn)象,總體上是同步的。2.地膜覆蓋對水稻-油菜輪作農田CO_2凈排放的影響(1)在水稻和油菜種植期間,農田表現(xiàn)為CO_2的匯,CO_2凈排放與溫度相關性不顯著,CO_2的吸收主要是來自植物植株的貢獻,土壤呼吸對CO_2凈排放的影響小;在作物營養(yǎng)和生殖生長旺盛的中后期,農田中CO_2的吸收量增加明顯,而且CO_2的吸收受天氣狀況(陰/晴)的影響顯著。(2)在水稻和油菜種植期間,農田對CO_2吸收量的差異主要表現(xiàn)在作物生物量的不同。通過兩年的實驗發(fā)現(xiàn):第二年覆膜增加農田CO_2的吸收量,覆膜比不覆膜增加9%;而第一年覆膜處理降低了農田CO_2的吸收量,覆膜比不覆膜降低27%。3.地膜覆蓋對水稻-油菜輪作農田溫室氣體綜合全球增溫潛勢(GWP)的影響(1)在水稻-油菜輪作農田中,農田整體表現(xiàn)為碳匯。三種主要溫室氣體(CH_4、N_2O、CO_2)的綜合GWP為負值。第二年和第一年農田中覆膜/不覆膜的綜合GWP分別為-34075/-29682 kg CO_2·hm~(-2)yr~(-1)和-16079/-24479 kg CO_2·hm~(-2)yr~(-1),第二年和第一年覆膜比不覆膜分別增加或減少了+15%和-34%。(2)在水稻-油菜輪作農田中,CH_4、N_2O溫室氣體的GWP為正貢獻,第二年覆膜/不覆膜CH_4、N_2O的GWP分別為1059/503 kg CO_2·hm~(-2)yr~(-1)、4869/6352 kg CO_2·hm~(-2)yr~(-1),與第一年相比,CH_4、N_2O覆膜/不覆膜分別增加或減少了+41%/-3%、+49%/+155%。地膜覆蓋降低農田CH_4、N_2O、CO_2三種氣體的GWP貢獻值,地膜覆蓋使農田CH_4氣體的GWP貢獻值增加,而地膜覆蓋對N_2O氣體GWP貢獻值的影響比較復雜。4.地膜覆蓋對水稻-油菜輪作農田土壤理化特性的影響在水稻-油菜輪作農田中油菜生長期間,地膜覆蓋使土壤含水率、微生物量碳(SMBC)、可溶性有機碳(DOC)、微生物量氮(SMBN)有不同程度的降低,覆膜土壤的溫度、土壤有機碳、脲酶活性有不同程度的增加,而其他土壤理化性質覆膜和不覆膜差異不明顯(如:pH值、土壤總氮、堿解氮等)。
[Abstract]:In recent decades, the concentration of greenhouse gases in the atmosphere has been increasing, and the enhanced greenhouse effect has become a global environmental problem. In addition to the combustion of chemical fuels, agriculture is an important source of greenhouse gases produced by human activities. The use of film mulching technology is a "white revolution" in agricultural production in China, from the last world. Since the introduction of film mulching technology in 70s, this technology has been widely used in China. After the film covering, a physical barrier between the film and the soil has been set up, which directly obstructed the vertical evaporation of water, blocked the exchange of air flow between the near surface layer and the atmosphere, increased the resistance of light and heat exchange, and made the soil temperature, light, and water in the membrane. The ecological conditions such as fertilizer and gas have changed. What are the effects of the film mulching on the emission of greenhouse gases and carbon fixation in the farmland ecosystem? In the context of the warming of the global climate, these are the scientific problems that need to be solved urgently. Elephant, at the key field scientific observation test station of the purple soil ecological environment in Southwestern University, Chongqing City, Chongqing City, the law of film mulching on major greenhouse gases (CH_4, N_2O and CO_2) emission and its influencing factors were studied. The environmental factors of farmland are complex and changeable, so on the basis of the completed first year experiment (from 05 months to 04 months of 2015 2014), the field observation experiment of second years (2015 05 months to 2016 04) has been added. The main results are as follows: 1. the effect of 1. film mulching on rice rape cropland cropland, N_2O emission (1) in rice rape cropland, CH_4 emission flux and temperature have a significant positive correlation, and the emission concentration of CH_4 appears in rice and rape planting. During the first and second years, the film mulching increased by 44% and 110%. (2) in rice rape cropland, and the emission of N_2O was less affected by temperature (n=47, P0.05) and N_2O in the first and second years. The emission of N_2O emissions is often related to the fertilization of farmland and the dry and wet soil of the soil. After the fertilization of farmland, the release amount of the rape during the cropland planting accounts for most of the release of N_2O in the farmland (more than 90%). The effect of the film on the N_2O emission of farmland is more complex: the emission of N_2O in the mulched farmland covered by the rainy and wet winter season is reduced by second years (second years). The emission of N_2O in the dry winter covered field covered farmland was increased by 33% (first year). (3) in rice rape cropland, the results of two years' experiments showed that during the growth of rice, the emission characteristics of two kinds of greenhouse gases, CH_4 and N_2O, were "this elimination" and two kinds of N_2O two species in spring farmland in the high temperature and less rain. The peak time difference between the gas emission and the peak time will increase. In the period of rape growth, the CH_4, N_2O and two kinds of greenhouse gases in the farmland did not appear "the difference". In general, the effect of the synchronous.2. film mulching on the net emission of CO_2 in the rice rape cropland was (1), during the planting of rice and rape, the farmland was expressed as the sink of CO_2, CO_2 The correlation between net emission and temperature was not significant. The absorption of CO_2 was mainly from plant plants, and the effect of soil respiration on the net emission of CO_2 was small. In the middle and late stages of crop nutrition and reproductive growth, the absorption of CO_2 in farmland increased significantly, and the absorption of CO_2 was significantly affected by the weather conditions (yin / sunny). (2) in rice and Rape Species During the period of planting, the difference in the amount of CO_2 absorption in farmland was mainly in the difference of crop biomass. Through two years' experiments, it was found that the second year film increased the absorption of CO_2 in farmland and increased the film mulching ratio by 9%, while the film mulching treatment reduced the amount of CO_2 absorption in the first year, and the film mulching was less than the film covered by the film covering the rice rape wheel. The influence of the integrated global warming potential (GWP) on farmland greenhouse gas (1) in the rice rape rotation farmland, the whole field of farmland is carbon sink. The comprehensive GWP of the three major greenhouse gases (CH_4, N_2O, CO_2) is negative. The second year and the first year of the farmland covered / non plastic film combined GWP are -34075/-29682 kg CO_2 hm~ (-2) yr~ 24479 kg CO_2. Hm~ (-2) yr~ (-1), second and the first years of film mulching increase or decrease respectively +15% and -34%. (2) in rice rape rotation farmland, CH_4, N_2O greenhouse gas GWP contribution, second years of film / no covering CH_4. Compared with the first year, the CH_4, N_2O coated / non coated film increased or reduced +41%/-3% respectively, and the +49%/+155%. film covered the GWP contribution of three kinds of gas, CH_4, N_2O, CO_2, and the film mulching increased the GWP contribution of CH_4 gas in farmland, while the influence of film mulching on N_2O gas GWP contribution was more complex. Soil moisture content, microbial biomass carbon (SMBC), soluble organic carbon (DOC) and microbial biomass nitrogen (SMBN) have different degrees of decrease in soil moisture content, soil organic carbon (DOC), soil organic carbon and urease activity, and soil organic carbon and urease activity in different degrees, and other soil in other soils. The physical and chemical properties of film mulching and no plastic mulching were not significantly different (such as pH, total nitrogen and alkali hydrolyzable nitrogen).
【學位授予單位】：西南大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：S511;S565.4;X712

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