| Water management is particularly important during rice planting, and it impactsgreenhouse gas emissions law by different water conditions affecting soil moistureand redox conditions. Jilin Qianguo has a rich land resources, in order to alleviate theecological damage to local land growing salinization, continued to carry out alarge-scale development projects for saline paddy fields and ecological managementof repair. So far, history of Qianguo paddy field development is more than60years,and it protects the security of the country food production. However, due to its featureof high carbonate deposits, in which the development of large-scale diversionirrigation, greenhouse gas emissions of paddy have become a part of regional climatechange that should not be ignored.The study was supported by my tutor’s National Natural Science FoundationProject——Soil organic carbon change mechanism and warming potential researchof saline-alkali paddy soils throughout the year in Jilin Province. This paper, whichchose the saline paddy soil of Qianguo County in the west of Jilin province as theresearch object, through the combination of field sampling and plot experiment,studied characteristics of paddy greenhouse gas emissions during growing periodunder different water management models respectively, monitored the changes in thefield of soil temperature and soil moisture, studied the comprehensive greenhouseeffect by water treatment, analysis of greenhouse gases contribution rate to thecomprehensive greenhouse effect during growing season, and explored the causes ofwater management impact on greenhouse gas emissions.By monitoring the plot experiments of57a and1a developed paddy underdifferent water management conditions found:1a paddy had lower greenhouse gasemissions and its emissions characteristics have no relationship of development years,CH4emission peak appeared lagging behind five days in the case of floodingtreatment conditions than intermittent irrigation of paddy fields and last long time.The cumulative amount of CH4emissions of flooded paddy field was always higherthan paddy field under intermittent irrigation. During growing season, CO2emissionsin paddy fields showed slightly decreased after the first rise, and then there was a slight recovery trend. N2O emissions trends basic distinct peaks appeared three timeswith significant seasonal variation, N2O emissions in maturity were slight fluctuations.N2O emissions trends were similar under different water management. Compared tointermittent irrigation, N2O emissions were slightly less in flooding process.According to the IPCC Fourth Report, the greenhouse effect calculated underdifferent water management has been produced, because of the advantages of CO2emissions (more than50%), the total greenhouse effect both reduced than intermittentirrigation of different developed flooded paddy, only distinct in quantity. Butintermittent irrigation can significantly reduce greenhouse effect in paddydevelopment process due to CH4and N2O.The field rice experiments greenhouse during growing season gas emissionswere monitored, CH4and CO2emissions law was consistent with the plot tests, butthe peak of N2O gas appears delay than the plot tests. Also, soil moisture and soiltemperature during growing season were monitored, the results showed: changes insoil moisture showed a tendency to decrease after the increase during the growingseason. The average greenhouse gas flux emission had no significant correlation withsoil moisture. Soil temperature increased first and then decreased, it was in line withthe change of greenhouse gas.This paper calculated that the total greenhouse effect was less than the measuredfield plot test results, compared to the field rice experiments, the difference of CH4and CO2gases contribution rate in plot test was small, but there are some differencesbetween the N2O gases contribution rates in the plot test.By calculating the experimental test data, the results showed, the totalgreenhouse effect in the field were lower than the results of the plot simulationexperiment, the CH4and CO2gas contribution rate have slightly difference with plotexperiments, but There are differences of the N2O gases contribution rate between thefield and plot test. The results of this research, validate and improve the results ofprevious studies in plot tests further, lay a foundation for further study of greenhouseeffect caused by the saline paddy land use and development process and provide localdata to support research in the area of global climate change. |
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