例句與用法

1. when soil antecedent condition is dry and the initial rainfall intensity is high, peak surface runoff also considerably lag behind that of rainfall, because of the formation of temporary relative impermeable top layer; b ) surface runoff is controlled primarily by infiltration-excess runoff mechanism under unsaturated condition; the major fraction of surface runoff are dominated by saturated infiltration-excess runoff response, only a small fraction by return flow mechanism when soil is saturated; c ) subsurface flow is dominated by saturated runoff mechanism, and the duration of subsurface post the rainfall end is dependent upon rather the soil properties than the rainfall characteristics; d ) subsurface flow intensity in cultivated soil layer ( 0 ~ 20cm ) is high up to 35mm / h when rainfall intensity is up to 120mm / h, indicating the existing of macropores and pipe flow in cultivated layer
   2)耕作制下紫色土的產(chǎn)流主要機(jī)制是：1)當(dāng)雨前土壤含水量未達(dá)到飽和狀態(tài)時(shí)，表面產(chǎn)流起始時(shí)間有明顯滯后現(xiàn)象，這與紫色土的快吸水性和較多非毛管孔隙密切相關(guān)；當(dāng)雨前土壤較干燥，降雨初期雨強(qiáng)較大時(shí)，易形成臨時(shí)相對(duì)不透水表層，表面產(chǎn)流峰也有明顯滯后現(xiàn)象。2)表面徑流的產(chǎn)流方式主要是超滲產(chǎn)流，當(dāng)土壤達(dá)到飽和狀態(tài)后，有四川大學(xué)博士學(xué)位論文小部分回歸流發(fā)生，但主要是飽和超滲產(chǎn)流發(fā)生，因?yàn)樽仙恋南鄬?duì)不透水層和其它透水障礙層不明顯。3）壤中流主要是飽和產(chǎn)流，與降雨過程有明顯的滯后，而且雨停后的壤中流產(chǎn)流歷時(shí)與降雨特征無關(guān)。