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红壤坡地季节性干旱严重危害农业生产和区域发展。季节性干旱时间上多发生于夏末秋初,但其空间发生特征及原因尚不明确。对2006年和2012年两年的坡耕地7、8月份土壤水分时空变化特征的研究结果表明:0~60 cm土壤含水量随土层深度增加而提高;且表层土壤含水量波动最剧烈,随土壤深度增加,波动减弱,60 cm土层土壤含水量变化极小。林地、草地、裸地和农田四种土地利用方式中,农田最易发生季节性干旱,且主要发生在0~30 cm表层土壤。作物根系分布和根系吸水是导致该区季节性干旱的主要原因,土壤蒸发是另一原因。促进作物根系下扎将是缓解该区季节性干旱的有效途径。
Seasonal drought in red soil slopes seriously jeopardizes agricultural production and regional development. Occurred in seasonal drought time in late summer and early autumn, but the spatial characteristics and causes are not yet clear. The results of spatio-temporal variations of soil moisture in July and August in sloping farmland in 2006 and 2012 show that the soil water content in 0-60 cm soil layer increases with the depth of soil layer, and the fluctuation of surface soil moisture is the most The depth of soil increased, the fluctuation weakened, and the change of soil water content in 60 cm soil layer was minimal. Among the four land use types of forestland, grassland, bare land and farmland, the seasonal drought is most likely to occur in farmland, which mainly occurs in 0-30 cm surface soil. The distribution of root crops and root water absorption are the main causes of seasonal drought in this area. Soil evaporation is another reason. It is an effective way to alleviate the seasonal drought in this area by promoting the root system under crops.