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确定水流阻力不仅有助于定量土壤栕魑飽大气连续体（SPAC）描述的水分传输过程，而且对建立减少水流阻力的节水农业措施，解决红壤区季节性干旱有重要意义。本文研究了不同耕作制度下作物气孔阻力日变化及其与蒸腾速率、土壤基质势、作物叶水势的关系，并分析了水流阻力的分布及其日变化规律。结果表明气孔阻力和蒸腾速率受作物种类和耕作制度影响，气孔阻力随着70cm土层以上土壤基质势的变化而变化；SPAC中叶气系统水流阻力为109～1010u001aS，是作物体水流阻力的1000倍，而后者又是70cm以上土层土壤水流阻力的100倍；作物体水流阻力大小顺序为：大豆＞花生＞玉米＞甘薯，除甘薯外，其它作物体水流阻力有明显的日变化；此外，耕作制度也影响作物体水流阻力。
Determining water flow resistance not only helps to quantify the water transport process described by SPAC, but also has important implications for establishing water-saving agricultural measures to reduce water flow resistance and for solving seasonal drought in red soil regions. The paper studied the diurnal variation of stomatal resistance and its relationship with transpiration rate, soil matrix potential and crop water potential under different tillage systems. The distribution of water flow resistance and its diurnal variation were also analyzed. The results showed that stomatal resistance and transpiration rate were affected by crop species and tillage system, and stomatal resistance varied with soil matrix potential above 70 cm soil layer. The flow resistance of leaf system in SPAC was 109 ~ 1010 u001 aS, 1000 times, and the latter is 100 times higher than that of soil above 70cm. The order of flow resistance of crops is soybean> peanut> maize> sweet potato. The flow resistance of other crops except sweet potato has obvious diurnal variation. In addition Tillage systems also affect crop flow resistance.