绿肥压青粉垄保护性耕作对稻田土壤温室气体排放的影响

2016-2018年，在广西农业科学院试验田设置粉垄耕作与常规耕作2种耕作模式，并设不施肥、常规施用化肥、单倍绿肥压青+化肥和双倍绿肥压青+化肥4种施肥处理开展连续田间定位实验，2018年早稻插秧5d后开始采用分离式静态箱-气象色谱法连续对稻田温室气体排放通量进行测定，研究绿肥压青下不同耕作模式和施肥处理稻田主要温室气体排放特征及其定位累积效应，分析温室气体累积排放量和增温潜势，以期为粉垄保护性耕作方式和施肥管理模式提供参考依据。结果表明：粉垄耕作模式下常规施用化肥处理中CO2排放通量是常规耕作模式下的2.3倍，施用双倍绿肥处理稻田CH4排放峰值是化肥处理中的2.5～3.9倍。各处理中，粉垄耕作下单倍绿肥加化肥处理稻田CO2和N2O累积排放量均最少，分别为1469.29kg·hm-2和36.61g·hm-2。两种耕作模式下施用单倍绿肥加化肥CH4累积排放量均低于双倍绿肥加化肥的处理。可见，合理配施绿肥加化肥对粉垄耕作下水稻温室气体CO2和N2O减排有一定积极作用，稻田CH4排放量与绿肥压青量相关，温室气体的增温潜势也相应受到影响。在一定时间尺度上，绿肥压青下粉垄保护性耕作是一种减少和遏制农业温室气体排放的有效措施。

Effect of Conservation Tillage with Smash Ridging under Green Manure Condition on the Emission of Greenhouse Gas in the Rice Field Soil

This continuous field positioning experiment was carried out in the experimental field of Guangxi Academy of Agricultural Sciences from 2016 to 2018 with setting two kinds of farming modes, including the smash ridging and the conventional tillage, along with setting up blank control with no fertilizer, conventional application of chemical fertilizer, single green manure and chemical fertilizer and double green fertilizer and chemical fertilizer 4 kinds of fertilization treatments. After 5 days of rice transplanting in 2018, the greenhouse gas emission flux of rice fields was continuously measured by separate static chamber-meteorological chromatography to study the main greenhouse gas emission characteristics and their cumulative effects of different tillage patterns and fertilization treatments under green manure and analyze the cumulative emission of greenhouse gases and the potential of warming, in order to provide reference for the conservation of tillage and fertilization management mode. The results showed that the CO2 emission flux of conventional fertilizer treatment under the smash ridging was 2.3 times that of the conventional tillage mode. The CH4 emission during the critical period of the rice field peak under the application of double green manure is 2.5 to 3.9 times that of the action of chemical fertilizers. In each treatment, the cumulative CO2 emission from paddy field treated with single-green manure plus chemical fertilizer was the lowest, which was 1469.29kg·ha-1, and the cumulative N2O emission was the least, which was 36.61g·ha-1. The cumulative emission of CH4 from single green manure plus chemical fertilizer under the two farming modes was lower than that of double green manure plus chemical fertilizer. Rational application of green manure plus chemical fertilizer has a certain positive effect on the reduction of greenhouse gas CO2 and N2O emission under the smash ridging mode. The CH4 emissions in paddy fields were related to the green manure volume and the warming potential of greenhouse gases was also affected accordingly. On a certain time scale, applying the conservation tillage with green manuring and smash ridging is an effective measure to reduce and contain agricultural greenhouse gas emissions.