| This research sets three different treatments in positioning for four consecutive years including drip irrigation (D30), drip filtration irrigation (S30) and furrow irrigation (G30). By the method of static box gas chromatograph, the N2O, CO2 and CH4 emission flux were observed in tomato growing season. Analyzing its influence factors and using the real-time fluorescent quantitative PCR technology to research the soil microbial activity which affects greenhouse gases emission, the eventual aim is to establish the reasonable water-saving irrigation schemes for vegetable cultivation. The main research results are as follows:With the different irrigation methods and single irrigation amount, the water migration way and the speed in the soil is not same. These will cause the different soil physical and chemical properties and biological properties, which can lead to different soil greenhouse gas emissions, different crop growing conditions, influenced yield. Comparing with the different treatment’s tomato yield, D30 is maximum, S30 second, G30 minimum. The irrigation methods are not significant difference with crop quality.The change rule of greenhouse soil N2O emission is dynamic with irrigation and three times of fertilizer and present more peak, on the same fertilizing amount basis, irrigation is the main factor affecting the N2O emissions in tomato’s rowing season. The range of N2O emissions is between 10.04-25.33 kg N hm-2.G30 treatment is maximum, D30 treatment second, S30 treatment minimum. It is consistent with every treatment’s single irrigation amount. During the entire period of tomato growth, soil temperature (5 cm) is the best temperature of soil microbial activity.N2O emission flux in a comfortable soil temperature appears very significant positive correlation with WFPS and nitrate nitrogen contents. The different irrigation methods, leading to significant difference with soil microbial biomass nitrogen content, soil ammonia oxidizing archaea gene copy number and soil denitrifying bacteria gene copy number of significant. Soil N2O emission mainly comes from the soil denitrification process.The change rule of greenhouse soil CO2 emission is in line with the temperature and soil temperature (5 cm), and has obvious seasonal variation.CO2 emissions range is between 9.53-11.84 t C hm-2, and S30 treatment is the largest, G30 treatment second, D30 treatment minimum. The soil temperature (5 cm) and temperature are the important environmental factors to affect the CO2 emissions of tomato growing season. The different irrigation methods, leading to significant difference with soil microbial biomass carbon content and soil CO2 fixation bacterial gene copy number. Microbial biomass carbon content and soil CO2 fixation bacterial gene copy number size order consistent with soil CO2 emissions.Soil CH4 emission flux tends to absorb in most of the time for tomato growing season. Three irrigation treatments show atmospheric CH4 sink. Each irrigation treatment’s CH4 absorption amount in the scope of 0.71 to 1.98 kg C hm-2.S30 treatment is maximum for total absorption of CH4, but D30 treatment take second place, G30 treatment is minimum. Soil moisture is the main factor to affect CH4 emission. The different irrigation methods, leading to significant difference with soil methanogens gene copy number. The soil methanogens gene copy number size order consistent with soil CH4 emissions.Therefore, taking comprehensively into account irrigation amount, the greenhouse gas emissions and vegetable yield in the tomato growing season, the best irrigation method is drip irrigation, which can not only achieve the goal of high yield, high efficiency and water saving, but also decrease the amount of greenhouse gas emissions, even slow global warming. |
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