Study On Soil Moisture Dynamics Of The Mixed Plantation Of Manchurian Ash

In order to research the water conservation function of Ash plantation, factors of different stands, such as biomass and hydrological parameter of litter, soil moisture content as well as dynamics were investigated in the mixed and pure stands of Manchurian ash. Results are as follows:1 the holding water ratio of litter layer of Fraxinus mandchurica and Pinus koraiensis mixed forest was maximize, the alteration range of these stands style varied from 9.05mm to 15.82mm,among of thest, the maximize water holding of Fraxinus pure forest was 12.82mm. 2 Each style of stand were all increased in the soil bulk density with the increment of the thickness.3 Soil capillary porosity decreased with the increase of the soil thickness in every stand, among them the decrease variety range of Fraxinus mandchurica and Pinus koraiensis mixed forest was minimum, the ratio of the soil non-capillary porosity in sequence as: Fraxinus mandchurica and Larix mixed forest (17%)> Fraxinus mandchurica and Pinus koraiensis mixed forest (15.5%)> Fraxinus mandchurica pure forest (12%)> Fraxinus mandchurica and spruce mixed forest (9.1%). 4 The water-holding capacity calculated according to actual soil thickness saturated in different stands was varied from 2871 to 3035t.hm^-2,among them, the saturated water-holding of Fraxinus mandshurica and Pinus koraiensis mixed forests was maximize, but Fraxinus mandshurica pure forest was minimum. 5 The rule of infiltration were the same in four style of stands, that was with the deeper soil layer, the lower speed of soil infiltration of water; among the style of stands the speed of soil infiltration in Fraxinus mandchurica pure forest was higher than other three Fraxinus mandchurica mixed forest, of which, the infiltration function of Fraxinus mandshurica and Pinus koraiensis mixed forest was the worst.(6)In the direction of horizon, the water-holding capillary in low layer of forest had a larger trend than in the gap of forest, in the direction of vertical, the soil moisture changed obviously, with the soil depth increase by degrees, according to the water-holding capillary and the water absorbability of the roots, the soil moisture divided into tree layers. 7 In the scale of time, the distribute rule of soil moisture was coincided with the precipitation in correspond period, this showed that the soil moisture was effected by the character of precipitation before the corresponding measure period. According to the long time observation of the experimental area, the dynamic change of the soil moisture was divided into: consuming period, accumulating period, losing and stabilizing period from March. It can be concluded that Ash and conifer mixed forest is not only suitable for industrial wood forest but also for cultivating water conservation forest.