土壤耕作与秸秆还田对江西双季稻产量和温室气体排放的影响

发布时间：2018-04-20 14:48

本文选题：气候变化 + 粮食安全　；参考：《中国农业科学院》2015年硕士论文

【摘要】：水稻是我国最主要的粮食作物之一,60%以上的人口以稻米为主食。稻田是农业环境中CH4排放的重要来源,约占全球人为排放量的1/4。如何在持续提升水稻产量的同时,减少农田温室气体的排放,实现高产低碳稻作已经成为亟待解决的重要科学问题和生产技术。已有研究表明,土壤耕作措施和秸秆还田均可以影响稻田温室气体排放,但对其交互效应尚不明确。因此,本文以我国主要的水稻生产区域-双季稻区为研究对象,开展了不同耕作方式和秸秆还田方式对双季稻区水稻生产力和稻田温室气体排放影响的研究,同时在100年的尺度上评价不同处理下稻田的周年温室效应。主要研究结论如下:(1)与翻耕相比,旋耕条件下早稻和晚稻的产量均较高,但差异不显著;秸秆还田显著提高早稻和晚稻的产量。水稻产量的高低主要取决于有效穗数和穗粒数。其中,晚稻产量主要受穗粒数的影响,与翻耕秸秆全量还田相比,翻耕根茬还田、旋耕根茬还田和旋耕秸秆全量还田处理下的穗粒数分别高出7.9%、23.9%和10.6%;早稻产量则主要受有效穗数的影响,与旋耕秸秆全量还田相比,翻耕根茬还田、翻耕秸秆全量还田和旋耕根茬还田处理有效穗数分别高出约13.7%、6.2%和21.6%。(2)秸秆还田显著增加了早稻和晚稻稻田CH4的排放,但降低了冬闲期CH4的排放。与旋耕相比,翻耕显著降低了两季水稻稻田CH4的排放,但对N2O的影响不显著。早稻和晚稻稻田CH4排放均呈现出双峰的趋势,但第一个峰值出现时间有所不同,晚稻峰值出现在分蘖盛期,而早稻峰值出现略晚。与根茬还田相比,翻耕方式下晚稻季、冬闲和早稻季秸秆换全量还田下CH4排放量分别增加了47.3%、26.1%、5.4%,旋耕方式下则分别增加了39.7%、7.1%、6.1%。与旋耕相比,根茬还田下晚稻季、冬闲、早稻季翻耕处理的CH4排放分别降低了96.1%、45.4%、30.0%;而秸秆全量还田下则分别降低了约86.0%、82.7%和30.8%。(3)在100年尺度上,CH4的排放量决定全球增温潜势(GWP)。本研究中,GWP呈现出和CH4累积排放量一样的趋势,即秸秆全量还田大于根茬还田,旋耕大于翻耕,且差异均达到显著水平。稻田温室气体排放强度(GHGI)由产量和GWP共同决定。GHGI在晚稻季趋势与GWP一致,而早稻季差异不显著。周年效应上,由于冬闲期CH4排放量较低,故GWP与CH4排放趋势一致,即秸秆全量还田显著大于根茬还田,旋耕显著大于翻耕。由于翻耕+根插还田处理中晚稻产量低,所以在翻耕秸秆全量还田处理中周年GHGI最低。因此,对于双季稻区而言,在翻耕方式下进行秸秆全量还田是一种较好的高产低碳稻作措施。
[Abstract]:Rice is one of the most important food crops in China. Rice fields are an important source of CH4 emissions in the agricultural environment, accounting for about a quarter of the world's anthropogenic emissions. How to continuously increase rice yield, reduce greenhouse gas emissions from farmland and realize high-yield and low-carbon rice cropping has become an important scientific problem and production technology to be solved urgently. Previous studies have shown that both soil tillage and straw return can affect greenhouse gas emissions from paddy fields, but the interaction effects are not clear. Therefore, the effects of different tillage methods and straw returning methods on rice productivity and greenhouse gas emissions from paddy fields were studied in this paper, which is the main area of rice production in China. At the same time, the annual Greenhouse Effect under different treatments was evaluated on the scale of 100 years. The main results were as follows: (1) the yield of early rice and late rice under rotary tillage was higher than that of tillage, but the difference was not significant, and straw returning to field significantly increased the yield of early rice and late rice. The yield of rice mainly depends on the number of effective panicles and the number of grains per panicle. The yield of late rice was mainly affected by the number of grains per panicle. The yield of early rice was mainly affected by the number of effective panicles, and the yield of early rice was mainly affected by the number of effective panicles, compared with the total amount of straw returned by rotary tillage, the number of grains per ear was increased by 7.9% and 10.6%, respectively, and the yield of early rice was mainly affected by the number of effective panicles. The number of effective spikelets of total tillage and root-stubble returning treatments were about 13.7% and 21.60.20% higher than that of tillage, respectively.) the CH4 emissions of early rice and late rice paddy field were significantly increased by straw returning, but the CH4 emission of winter idle period was decreased. Compared with rotary tillage, tillage significantly reduced the CH4 emission from two rice paddy fields, but had no significant effect on N2O. Both early rice and late rice paddy showed a double peak trend of CH4 emissions, but the first peak appeared in different time, the peak of late rice appeared at the peak of tillering period, and the peak value of early rice appeared a little late. Compared with the return of stubble to the field, the total CH4 emissions in late rice season, winter idle season and early rice season were increased by 47.3% 26.1% and 5.4% respectively under tillage, and 39.7% (7.1%) and 6.1% under rotary tillage, respectively. Compared with rotary tillage, the CH4 emissions of late rice season, winter fallow and early rice tillage were reduced by 96.1U 45.4V 30.0g, respectively, while the total return of straw was reduced by 86.0% and 30.8%, respectively. The CH4 emission of CH4 determined the global warming potential in 100 years. In this study, GWP showed the same trend as the cumulative emissions of CH4, that is, the total return of straw was greater than that of stubble, and the rotation tillage was larger than that of tillage, and the difference reached a significant level. Greenhouse gas emission intensity (GHGI) from paddy field was determined by yield and GWP. The trend of GHGI in late rice season was consistent with that of GWP, but there was no significant difference in early rice season. Because of the low CH4 emission during winter idle season, the trend of GWP and CH4 emissions was the same, that is, the total return of straw was significantly larger than that of stubble, and the rotation tillage was significantly larger than that of tillage. Due to the low yield of middle and late rice in the tillage and root planting treatment, the annual GHGI was the lowest in the total tillage straw returning treatment. Therefore, for the double cropping rice area, it is a better measure of high yield and low carbon rice to return straw to the field under tillage.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511.42;S181

【参考文献】