Management Measures In Paddy Field And Their Effects On Greenhouse Gases Emission

Global warming, which is caused by the increasing greenhouse gas(GHG) emission, has been a global concerned environmental problem. CO2, CH4 and N2 O are known as the main kinds of GHG. Paddy field, an important production base in China, plays a vital role in ensuring food security, and it is also the main source of GHG. There is a significant difference of GHG emission when different farm management measures are taken. Clarifying the characteristics of GHG emission, optimizing the management measures and realizing low carbon of production in paddy field, are meaningful for mitigating greenhouse effects and ameliorating climate change.In this study, firstly, the survey sites of paddy planting were chosen based on the natural factors and paddy planting characteristics in Hubei Province; secondly, the main planting patterns and associated farm management measures were defined by the on-the-spot investigation in those selected survey sites; at last, according to the status of paddy growing and planting habits, the characteristics of GHG emission under different farm management measures was simulated by DNDC model, then the effects of farm management measures on GHG emission in paddy fields were analyzed. The main conclusions are as shown below:(1) According to the survey, the most popular planting pattern in Hubei Province is paddy-upland fallow with tractor-ploughing, flooding-irrigation, fertilization and no straw returning. There are 39 households in this pattern, accounting for 9.63% of the surveys. Moreover, the main paddy management measures are tractor-ploughing, flooding-irrigation, paddy-rape rotation or paddy-winter fallow, fertilization, which account for 65.19%, 45.19%, 36.18% and 79.51%, respectively, among the total served farmer households.(2) There are different characteristics of GHG emission in paddy fields under different farm management measures. Changing planting mode mainly has an effect on the emission of CH4; the influence of Water management to rice field CH4 and N2 O emissions are mainly by changing Eh; paddy-upland rotation can effectively reduce GHG emission in paddy field; the effects of fertilizing management on the GHG emission has related with fertilizer kinds, amounts of fertilization, fertilizing methods and organic fertilizer.(3) The interaction between different management measures on GHG emission exists among different paddy planting modes. The interaction between no-tillage and straw-returning restrain GHG emission; while, the interaction among fertilizing organic and inorganic fertilizers and flooding-irrigation accelerates GHG emission.