He that provides not a cloak before the rain , may chance to be wet to his cost 不在雨前准备好雨衣的人就要冒淋湿的危险;不要等到下雨再做雨衣。
3.
When the rainfall intensity is steady , the time longer of rainfall is , the thinner of slope soil is , the more water in slope soil before rain is , the easier the water flows on the ground . 2 因此,在太行山片麻岩区,在一定的降雨强度下,降雨时间越长,坡面土壤层越薄,坡面土壤雨前的含水量越高,越容易形成地表径流。
4.
The main result is as follows : 1 . after erosion , the content of organic matter , total nitrogen and the available nitrogen in the sediment is more than that of soil sample . namely the enrichment phenomenon of organic matter , total nitrogen and the available nitrogen in slope cultivated land erosion soil is obvious 黄?土受侵蚀后,泥沙样中有机质、全氮和碱解氮的含量都高于雨前采集的坡地表层土样,即黄?土坡耕地水土流失中有机质、全氮和碱解氮流失的“富集”现象明显,而全磷和速效磷却无明显的“富集”现象。
5.
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 )耕作制下紫色土的产流主要机制是: 1 )当雨前土壤含水量未达到饱和状态时,表面产流起始时间有明显滞后现象,这与紫色土的快吸水性和较多非毛管孔隙密切相关;当雨前土壤较干燥,降雨初期雨强较大时,易形成临时相对不透水表层,表面产流峰也有明显滞后现象。 2 )表面径流的产流方式主要是超渗产流,当土壤达到饱和状态后,有四川大学博士学位论文小部分回归流发生,但主要是饱和超渗产流发生,因为紫色土的相对不透水层和其它透水障碍层不明显。 3 )壤中流主要是饱和产流,与降雨过程有明显的滞后,而且雨停后的壤中流产流历时与降雨特征无关。
6.
And we have got the following result : 1 . the technique of storing water in soil in gneiss area of tai - hang mountain : the more water in soil before rain is , the less water capability of soil is , the time shorter of water flowing from soil is , the easier the water flows on the ground ; the soil capability of reserving water of different soil thickness is terrace > acacia land > pine land > grass land , so the soil is more thick , the soil capacity which contains water is more large ; the accumulated water that flows on the ground is remarkable related with the logarithms of rain time 太行山片麻岩区土壤蓄水规律:雨前土壤含水量越高,土壤可蓄水量越小,出流所需时间越短,容易形成地表径流;不同土层厚度的土壤蓄水量为:梯田刺槐林地油松林地草地;累积地表径流量与降雨时间的对数呈显著正相关,拟合方程为w = a + blnt ,相关系数均大于0 . 92 ,即在降雨强度一定的前提下,降雨时间越长,累计地表径流量越多。