Experimental Study On Water Infiltration Of Different Underlying Surface In Qiugedong Ditch Watershed

The test selected typical underlying surface according to the classification of arbor, shrub, grass and crop,used the double loop method for determination of rainfall infiltration, done systematic research of soil water infiltration regular of different types of underlying surface in the Qiugedong Ditch Watershed. And done fitting regression analysis and the comparison and evaluation of for each test session infiltration curve obtained by experimental data through three kinds of models as Kostiakov empirical formula, Horton empirical formula, general empirical formula.The topography and land use factors on the influence of soil infiltration capability has discussed, the main research results are as follows:(1) In the test conditions of this watershed, Kostiakov empirical formula can be cooperate best with the measured values in the transient phase; Horton empirical formula in high fitting degree in the transitional phase and the stable infiltration phase; General empirical formula is ineffective in the transient phase, although Horton empirical formula is better than General empirical formula in the transitional phase, but the difference is not too obvious. General empirical formula fitting degree is high in the stable infiltration stage, but Horton empirical formula is almost the same formula. In aggregate, Horton empirical formula is more suitable for this watershed. (2) The soil initial infiltration rate at the Qiugedong Ditch Watershed is between 0.796-4.896 mm/min, the minimum value appeared on the walnut forest land under the half cloudy slope, the maximum value appeared on the potato farmland under the half sunny slope.The gap between the maximum and the minimum is 5.15 times.The steady infiltration rate changed between 0.476-1.232 mm/min, the minimum and minimum value gap is 1.59 times, the maximum appeared on the pinus tabulaeformis forest land under the half sunny slope, the minimum appeared on the corn farmland under the half sunny slope. The cumulative infiltration volume of 30 min ahead changed between 14.72-70.43 mm, the maximum value appeared on the potato farmland under the half sunny slope, the minimum value appeared on the walnut forest land under the half cloudy slope. (3) The greater the slope gradient, the smaller the initial infiltration rate and stable infiltration rate, the longer to reach steady infiltration stage. Due to the difference of litter layer of vegetation status, the initial infiltration rate of the sunny slope is greater than the shady slope and the steady infiltration rate is lesser. The impact on the infiltration of slope positions is the soil steady infiltration rate increase gradually from top to down of the slope positions. (4) The size relations of surface soil bulk density (0-20 cm) under different land use types of the underlying surface are:corn< millet < potatoes< grassland< elm< pinus tabulaeformis< seabuckthorn< poplar< north China larch< armeniaca sibirica< walnuts.The size relations of initial soil moisture content basic between 5%-10%range,the average soil moisture content within the scope in 0-20 cm soil depth of the underlying surface are shown as:millet< potatoes< corn< grassland< elm< north China larch< walnut< seabuckthorn< armeniaca sibirica< pinus tabulaeformis< poplar.(5) The initial infiltration rate of the underlying surface under different land use types is shown as:walnut< north China larch< armeniaca sibirica< poplar< pinus tabulaeformis< elm< seabuckthorn< grassland< millet< corn< potatoes,Overall the size of the relationship is:the arbor forest land< the shrub forest land< the grassland< the farmland.The steady infiltration rate of the underlying surface under different land use types is shown as:corn< millet< potatoes< grassland< seabuckthorn< walnuts< elm< poplar< north China larch< armeniaca sibirica< pinus tabulaeformis,Overall the size of the relationship is:the farmland< the grassland<the shrub forest land< the arbor forest land. The pinus tabulaeformis with good infiltration performance can be used as a fine tree species of soil and water conservation.Forestland infiltration performance is better than that of grassland and farmland, through afforestation can dammed-up rainfall, increase the infiltration, prevent and control of soil erosion.