| In order to choose the most suitable kinds of trees and grasses and the patterns among them in the process of converting slope land into forest and pasture, the study about soil's hydrological-physical characteristics and mechanism of rainfall-infiltration-runoff is made. The results indicate that:(1) Compared with that of agricultural land, the improvement of the soil's hydrological-physical characteristics, including soil unit weight, pore rate, water holding capacity and permeability etc, is little in the soil horizons of 0~20cm, while it is significant in the horizon of 20~40cm. Of all these kinds of forests, it is the mixed forest of Alnus cremastogyne & Cupressus funebris that has the best effects on the soil improvement.In addition, the soil hydrological-physical characteristics of the surface soil horizon in the profiles are better than those of the 20~40cm layer.(2)The amount of the litter differ each other in the different forest-types, and the litter interception losses change greatly, too. The modified interception losses vary from 1026.1t·km-2 to 4058.781 · km-2 ,and the average is 2214.091 · km-2 .All of them, the litter layer in the Pinus elliottii woods II has the maximum interception capacity , then the mixed forest of Alnus cremastogyne & Cupressus funebris followed, and the little Robiuia pseudoacacia is minimum. Further more, the natural moisture content of the litter has a cycle change with the time passing.(3)The varieties of soil moisture content in different soil horizon differ. And it shows in common that the change in the surface soil(0~15cm) is more accurate than that in the subsurface(15~30cm) and in the third horizon(30~50cm). The woodlands have little change in moisture content compared with the agricultural land.(4)The critical rainfall of the agricultural land is from 6.5mm to 10mm, and forest land from 10mm to 20mm. The critical rainfalls are different, which mixed forests have higher ones than pure forests. Among them, the maximum critical rainfall are the patterns of Pinuselliottii & Coriaria sinica and Pinus elliottii & Robiuia pseudoacacia & Cyclobalanopsis glauca, and the minimum is the one of pure Castanea mollissima.(5)The time before runoff correlates with these factors including the volume of rainfall, the average intensity before runoff, the soil original moistureure content and the vegetation coverage etc. According to the evaluation of the eco-hydrological effects which the time before runoff put on vegetation types, mixed forests have the best effects, and pure forests followed, and the agricultural land is the last one. The study also indicates that the patterns of Pinus elliottii & Coriaria sinica., Pinus elliottii & Robiuia pseudoacacia & Cyclobalanopsis glauca, Pinus elliottii & Alnus cremastogyne and pure Alnus cremastogyne woods have better eco-hydrological effects than the others.(6)The relation between the volume of runoff and the intensity of rainfall reflects the regulating ability of the surface conditions to the rainfall. It shows that the abilities of rainfall controlling of the Pinus elliottii & Alnus cremastogyne and Pinus elliottii & Quercus acutissima and Pinus elliottii & Coriaria sinicaand the Pinus elliottii & Robiuia pseudoacacia & Cyclobalanopsis glauca are the highest, and that of the pure Alnus cremastogyne followed closely, and the Castanea mollissima, Coriaria sinica and agricultural land lowest.(7) Different coverages have different volume of runoff in the same runoff field; and envn at the same coverage the same runoff field have the different volume also. Among them, the mixed forests show the maximum effects on reducing the amount of the runoff, the pure forests followed, the agricultural land hi the third.(8)The mixed forest patterns with good adaptation and eco-hydrological effects, such as Pinus elliottii & Alnus cremastogyne, Pinus elliottii & Coriaria sinica, Pinus elliottii & Robiuia pseudoacacia & Cyclobalanopsis glauca and so on, are suggested as the main pattern to apply in the process of conv...
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