华北平原优化农作条件下作物生产和温室气体减排研究

发布时间：2017-12-28 03:26

本文关键词：华北平原优化农作条件下作物生产和温室气体减排研究　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：华北平原是我国重要的粮食产区之一,冬小麦-夏玉米轮作是该区最主要的种植模式。近年来,高水肥投入实现了粮食高产,但同时也增加了温室气体排放。因此,在粮食高产稳产条件下实现资源高效和温室气体减排是我国农业可持续发展的迫切需求。针对氮肥过量施用和水资源紧缺的问题,2008年和2012年分别开展了不同种植模式(试验1)和硝化/脲酶抑制剂(试验2)的长期定位试验。试验1包括七个处理(模式):农民常规(CON)、优化(OPT)、免耕(NT)、节水Ⅰ(WSⅠ)、节水Ⅱ(WSⅡ)、保水(WR)和有机(ORG),该试验统筹了水氮管理、秸秆管理、耕作制度、种植制度等因素。试验2设置了五个处理:无氮(CK)、尿素(U)、尿素添加硝化抑制剂(NI)、尿素添加脲酶抑制剂(UI)和尿素添加硝化抑制剂+脲酶抑制剂(NIUI)。本研究基于以上两个长期定位试验,通过田间原位观测,系统的研究了多年来不同种植模式对作物产量、水氮利用、N_2O和CH4排放及净增温势(Net global warming potential,NGWP)和温室气体排放强度(Greenhouse gas intensity,GHGI)的影响;检验了多年硝化和脲酶抑制剂对粮食增产和N_2O减排的效果;分析了华北平原冬小麦-夏玉米轮作生产过程中土壤N_2O产生途径。主要研究结果如下:(1)与农民常规种植模式(CON)相比,优化种植模式可以有效的降低水氮投入,提高水氮利用效率。在6年的轮作周期中,通过平衡施肥和优化灌溉等措施,优化种植模式(OPT和NT)相比CON分别降低氮肥和灌溉水用量44%和33%,并保持产量不降低和高的稳定性,氮肥利用效率和灌溉水利用效率分别提高了 69-75%和43-48%。其它几种优化种植模式(WSⅠ、WSⅡ、WR和ORG)通过改变种植制度并结合水氮优化管理,相对于CON处理,虽然产量下降了22-61%,但是氮肥和灌溉水投入分别降低了 56-79%和46-64%,利用效率分别提高了 56-190%和11-57%。(2)与农民常规种植模式(CON)相比,6种优化种植模式均能显著降低N_2O排放量、NGWP和GHGI。N_2O排放、氮肥投入和灌溉耗电是农田温室气体的3大主要排放源;CH4吸收引起的固碳作用可以忽略。研究期间,OPT、NT、WSⅠ、WSⅡ、WR和ORG处理相比CON处理分别降低了 N_2O 排放 29%、30%、33%、40%、23%和 41%,NGWP 分别减少 31%、33%、46%、52%、48%和61%,每生产1吨粮食(以标准谷物产量为准)少排放199、204、220、207、42和206 kg CO2-eq。所有处理中N20排放、氮肥投入和灌溉耗电引起的温室效应占总排放的比例分别是15-22%、24-45%和23-45%。农田土壤是CH4的汇,但是由CH4吸收引起的固碳作用只能抵消农田温室气体净排放的1%不到。(3)尿素中添加硝化抑制剂(DMPP)不仅可以显著降低华北平原冬小麦-夏玉米轮作系统N_2O排放还可以提高产量和氮素利用率。脲酶抑制剂(NBPT)与DMPP共同使用时,DMPP的减排效果会被NBPT降低。经过3年试验发现,相比U处理,NI、NIUI和UI处理分别降低玉米季N_2O排放55%、40%和21%,分别降低小麦季N_2O排放47%、40%和33%。NIUI、NI和UI相比U处理分别增加年度产量7%、6%和4%,分别提高年度氮素利用率15%、10%和7%。(4)硝化作用对于施肥后N_2O排放峰值的贡献最多达40%,硝化微生物反硝化作用可能是施肥后N_2O排放的主要途径。DMPP通过抑制硝化作用和硝化微生物反硝化作用实现N20的减排。
[Abstract]:The North China Plain is one of the most important grain producing areas in China, and winter wheat and summer corn rotation is the most important planting pattern in this area. In recent years, high water and fertilizer input has achieved high grain yield, but also increased greenhouse gas emissions. Therefore, it is an urgent need for the sustainable development of agriculture to achieve efficient resources and greenhouse gas emission reduction under the condition of high and stable grain yield. Aiming at the problem of over application of nitrogen fertilizer and shortage of water resources, long-term location experiments of different planting modes (Experiment 1) and nitrifying / urease inhibitors (test 2) were carried out in 2008 and 2012 respectively. The experiment 1 consisted of seven treatments: mode CON, OPT, no tillage (NT), water saving I (WS I), water saving II (WS II), water holding (WR) and organic (ORG). The experiment integrated water and nitrogen management, straw management, cropping system and cropping system. In Experiment 2, five treatments were set up: nitrogen free (CK), urea (U), urea adding nitrification inhibitor (NI), urea added urease inhibitor (UI), urea adding nitrification inhibitor and urease inhibitor (NIUI). This study is based on more than two long-term experiments, through field observation, systematic study of the years of different planting patterns on crop yield, water and nitrogen use, N_2O and CH4 emissions and increase temperature potential (Net global warming potential, NGWP) and greenhouse gas emission intensity (Greenhouse gas intensity, GHGI) the effect of inspection; the effects of years of nitrification and urease inhibitors on grain production and N_2O emission reduction; analysis of winter wheat and summer maize in the North China Plain rotation in the production process of soil N_2O production pathway. The main results are as follows: (1) compared with the farmers' conventional planting model (CON), the optimized planting model can effectively reduce the water and nitrogen input and improve the efficiency of water and nitrogen utilization. In the 6 year of the rotation cycle, through balanced fertilization and irrigation measures, optimizing planting patterns (OPT and NT) in CON were reduced nitrogen fertilizer and irrigation water consumption of 44% and 33%, and to maintain production and high stability, nitrogen use efficiency and irrigation water use efficiency were increased by 69-75% and 43-48%. Several other optimization planting patterns (WS I and WS II, WR and ORG) by changing the cropping system and optimize water and nitrogen management, compared to CON treatment, while the yield was decreased by 22-61%, but the nitrogen fertilizer and irrigation water inputs were reduced by 56-79% and 46-64%, 56-190% and 11-57% to improve the utilization efficiency respectively. (2) compared with the farmers' conventional planting model (CON), the 6 optimized planting patterns could significantly reduce the N_2O emissions, NGWP and GHGI. N_2O emission, nitrogen fertilizer input and irrigation power consumption are the 3 main emission sources of greenhouse gas in farmland, and carbon sequestration caused by CH4 absorption can be ignored. During the study period, OPT, NT, WS I and WS II, WR and ORG compared with CON treatment were decreased by 29%, 30%, N_2O emissions of 33%, 40%, 23% and 41% NGWP, respectively, 33%, 46%, 31% reduction in 52%, 48% and 61%, each producing 1 tons of grain to grain yield (standard for 199, 204, less emissions) 220, 207, 42 and 206 kg CO2-eq. The proportion of greenhouse effect to total emission caused by N20 emission, nitrogen fertilizer input and irrigation power consumption in all treatment was 15-22%, 24-45% and 23-45% respectively. The farmland soil is the sink of CH4, but the carbon sequestration caused by CH4 absorption can only offset 1% of the net greenhouse gas emissions from farmland. (3) nitrifying inhibitor (DMPP) in urea can not only significantly reduce N_2O emissions from winter wheat summer maize rotation system in North China Plain, but also increase yield and nitrogen use efficiency. When urease inhibitor (NBPT) is used together with DMPP, the effect of DMPP reduction will be reduced by NBPT. After 3 years of experiments, it was found that compared with U treatment, NI, NIUI and UI treatments reduced the N_2O emissions by 55%, 40% and 21%, respectively, and reduced N_2O emissions by 47%, 40% and 33% respectively in the wheat season. Compared with NIUI, NI and UI, the annual output of U was increased by 7%, 6% and 4% respectively, and the annual nitrogen utilization rate was increased by 15%, 10% and 7%, respectively. (4) the contribution of nitrification to the peak value of N_2O emission after fertilization was up to 40%, and the denitrification of nitrifying microorganism was probably the main way of N_2O emission after fertilization. DMPP can reduce the emission of N20 by inhibiting nitrification and denitrification of nitrifying microorganisms.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S512.11;S513

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