关键词: 稻田, CH₄和N₂O排放通量, 水分管理, 水旱轮作, 土壤水分, 时空变化, 黄土塬区, 土地利用方式, 土壤干层

Abstract: CH₄ and N₂O fluxes from late-rice fileds in Guangzhou region were measured simultaneously by closed chamber method.The results show that the mean CH₄ fluxes are respectively 17.63,2.84 and 0.36mg·m^-2·h^-1 from the treatments of continuous flooding ,routine succession cropping and rice-vegetabele rotation,and the mean N₂O fluxes are 6.74,11.69 and 55.07 μg N₂O-N·m^-2·h^-1 correspondingly,which indicates that continuous floodin can greatly increase CH₄ emission,while sinnificantly reduce N₂O emission.Rice vegetable rotation is the reverse.There exists a trade off between CH₄ and N₂O emission.The factors affectin CH₄ and N₂O emssion are discussed,and the contribution of CH₄ and N₂O to global warming is preliminarily alalysed.

Key words: Rice field, CH₄ and N₂O fluxes, Water management, Rice-vegetable rotation, spatiotemporal variation, land use type, soil water, soil dry layer, Loess Tableland