Study On Cultivation Method And Plant Characteristics Of Rice On Methane Emission

In recent years,the area of hybrid rice cultivars and direct sowing rice have been increasing,it is vital to measure their methane emission flux and it is full of praxis signification to provide the environmental basis for direct sowing rice and hybrid rice development.In 2007,methane emission from the different culture methods were conducted, including translating rice(TR),broadcast sowing rice(BSR),drill rice(DR) from 16 varietis for early rice and late rice,also differences of methane emission were analyzed. The relationship of methan emission and botany characteristic of rice for different varietis and planting method.The main results were as follows.1.The differences of methane emission among rice cultivars were significant.The amount of methane emission and average methane emission flux between early rice and late rice,also transplanting and direct sowing were obvious different in experiment of 2007.For average methane emission flux,direct sowing was lower than transplanting and for methane emission,was higher than transplanting.The amount of methane emission and average methane emission flux were 6.21mg/m².h,14.53g/m² respectly for early rice and 10.56 mg/m².h,27.41g/m² respectly for late rice by broadcast sowing;which were 6.87mg/m².h,13.22g/m² respectly for early rice and 12.23mg/m².h, 26.39 g/m² respectly for late rice by transplanting.2.The dense of broadcast sowing influencing methane emissionThe methane emission in changing dense of broadcast sowing was different,the more densing,the more emission of methane.Comparing the average methane emission flux,it was 100 plant/m²ï¼ž80 plant/m²ï¼ž60 plant/m² in 9th July,23th July,6th August,19th August,30th August but except 11th September.3.The relationship of amont of methane-oxidizing,methanogenic bacteria and denitrifying bacteria in paddy.amont of methanogenic bacteria and methane-oxidizing,denitrifying bacteria in paddy was significant negative correlation respectively,the correlation were significant at 0.05 levels.The linear regression equation between methanogenic bacteria(Y)and methane-oxidizing,denitrifying bacteria were Y=11.531×X^-0.4121 and Y=11.987×X^-0.3232.4.Analyzing of rice plant and methane emissionThe correlations between the diameter of the 1st internode,the area of culm vascular bundles of 2st internode,the thickness of the 2nd internode stem wall,the transverse section area ratio of leaf sheath to the internode,the transverse section area ratio of 3st leaf sheath to the internode,The transverse section area ratio of stem wall to the internode and the methane emission were significant at 0.05 levels for 8 early rice.Methane emission to the the diameter of the 1st internode,the area of culm vascular bundles of 2st internode,the thickness of the 2nd internode stem wall,the transverse section area ratio of leaf sheath to the internode,the transverse section area ratio of 3st leaf sheath to the internode,The transverse section area ratio of stem wall to the internode was significant at 0.01 levels for 8 late rice.