基于大田试验对圩区稻田甲烷排放模型的研究

发布时间：2018-01-25 01:37

本文关键词： 稻田甲烷耕作肥料模型　出处：《安徽农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：以巢湖圩区稻麦轮作体系为代表,利用大田试验监测结果,对CH_4 MOD、DNDC模型优化、改进和筛选,尝试建立适合于长江中下游典型低洼圩区的稻田甲烷排放模型。大田实验设计空白对照(CK)、常规(CG)、保护性耕作(BG)、秸秆还田(CS)四种处理,采用静态箱-气相色谱法对试验田进行常规监测,以研究施肥与耕作对稻田CH_4排放的影响。结果表明:(1)实测数据表明,CK较CG,甲烷累计排放量下降4.85%,水稻产量下降21.48%;BG较CG,CH_4排放量下降7.88%,水稻产量上升1.48%;CS较CG,CH_4排放量上升47.06%,水稻产量基本不变。四种耕作方式之间除空白对照与常规无显著性差别,其余都存在显著性差别;(2)DNDC模型模拟出CK、CG、BG、CS四种处理的甲烷排放总量的误差大小分别为12.36%、3.37%、4.16%、3.68%,总体来看基本能较好模拟出各处理水稻季甲烷排放总量。甲烷日排放量的模拟值与实测值的相关系数分别为0.29、0.359、0.283、0.107,能较好模拟出CG处理的甲烷排放规律,对于CK、BG、CS等处理CH_4的排放规律的模拟,不够明显,其中对CS处理排放规律的模拟效果最差;(3)DNDC模型的敏感性分析表明,气温、土壤有机质、土壤质地是影响稻田CH_4排放量的重要因素。稻田CH_4排放量与气温、土壤有机质含量存在正相关性,与土壤粘土比例存在负相关性;(4)CH_4 MOD模型模拟出CK、CG、BG、CS四种处理的甲烷排放总量的误差大小分别为46.37%、42.98%、37.72%、12.75%,四种处理的模拟值较实测值均偏小,且CK、CG和BG三种处理的误差较大,CS处理较为接近。甲烷日排放量的模拟值与实测值的相关系数分别为0.701、0.550、0.544、0.464,对于CH_4排放规律的模拟效果较好,基本能模拟出其排放规律;(5)CH_4 MOD模型的敏感性分析表明,甲烷排放总量与气温、土壤砂粒含量、水稻品种系数成正比;与水稻生长内禀增长率、水稻初始地上生物量成反比;(6)以CH_4 MOD模型为框架,通过添加土壤有机质的分解、进行降水对Eh的修正、调整甲烷传输在各个路径的分配比例,得到的甲烷排放模型,其模拟出来的各个处理的甲烷排放总量与实测值接近,且模拟值与实测值的相关系数均达到极显著,能较好的模拟出巢湖圩区稻田甲烷排放规律。
[Abstract]:Taking the rice and wheat rotation system in Chaohu polder area as the representative, the model of CH_4 MOD DNDC was optimized, improved and screened by using the monitoring results of field experiments. A model of methane emission from paddy fields suitable for typical low-lying polder areas in the middle and lower reaches of the Yangtze River was established. Four treatments of returning straw to field were used to monitor the experiment field by static box-gas chromatography. The effect of fertilization and tillage on CH_4 emission from paddy field was studied. The results showed that the accumulative methane emission of CK decreased 4.85%, and the rice yield decreased 21.48%. The emission of BG was 7.88% lower than that of CGN CH4, and the rice yield increased by 1.48%. Compared with CGN Ch _ 4, CS increased by 47.06 and the rice yield remained unchanged. There was no significant difference between the four tillage methods except blank control and conventional cultivation, but there were significant differences between the four tillage methods. The error of the total methane emission from the four treatments is 12.36 ~ 3.37 and 4.16% respectively. The results show that the total methane emission error of the four treatments is 3.68% and 3.36% respectively. On the whole, it can simulate the total methane emission in rice season, and the correlation coefficient between the simulated value and the measured value of methane daily emission is 0.29 ~ 0.359 ~ 0.283 ~ 0.107, respectively. The methane emission law of CG treatment can be well simulated, but the simulation of CH_4 emission law of CK BGG CS treatment is not obvious enough, among which the simulation effect of CS treatment emission law is the worst. The sensitivity analysis of DNDC model showed that temperature, soil organic matter and soil texture were important factors affecting CH_4 emission from paddy field. There was a positive correlation between soil organic matter content and the proportion of soil clay. The total methane emission error of the four treatments was 46.37% and 42.98% (37.72%), respectively. 12.75, the simulated values of the four treatments are smaller than the measured values, and the errors of CKCG-CG and BG are larger. CS treatment is close. The correlation coefficient between the simulated value and the measured value of methane daily emission is 0.701g 0.550g 0.544N 0.464, respectively. The simulation effect of CH_4 emission law is good, and the emission law can be basically simulated. The sensitivity analysis of Ch _ 4 MOD model showed that the total methane emission was directly proportional to air temperature, soil sand content and rice variety coefficient. The initial aboveground biomass was inversely proportional to the intrinsic growth rate of rice. Based on the CH_4 MOD model, the methane emission model was obtained by adding the decomposition of soil organic matter, modifying the precipitation to Eh, and adjusting the distribution ratio of methane transport in each path. The total methane emission of each treatment is close to the measured value, and the correlation coefficient between the simulated value and the measured value is very significant, which can better simulate the methane emission law of paddy field in Chaohu Lake polder area.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X712;X16

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