Water Infiltration Process Of Pisha Sandstone Weathering Soil And The Effects On Ryegrass

Owe to its unique geological features and climates characterisitcs, the Pisha sandstone region is called as “the maximum of soil and water loss”. In this paper, we collected the undisturbed soil, laboratory simulate the soil infiltration test and the artificial pot plant in the outside the laboratory to study the effects of wearthering Pisha sandstone on plant nutrient,and mechanism of water infiltration processes of soil structural characteristics on weathering Pisha sandstone. For further theory basis research on weathering Pisha sandstone improve the newly construction soil on loess plateau, and provide technical support on wearthering Pisha sandstone recycling use. The main conclusions are as follows:1. In Heidaigou opencast dump, below 40 cm soil layer, the value of bulk density and saturated hydraukic conductivity has no significant difference. In the 0~40 cm soil layer, the value of bulk dnesity in the sandy soil are higher than in the loamy soil, but the saturated water content drcreased with the increase of soil bulk density. The soil organic matter in 0~40cm and 120~140 cm are higher than in other soil layer. The modeling soil column showed that the cumumlative infiltration increased with time in all the soil layers both in the sandy and loamy soil layer. Infiltration rate and cumulative infiltration decreased with the increase of soil depth in the stabilize infiltration. The Green–Ampt equation infiltration model described the infiltration processes well.2. Modified dump(newly configurated) soil column showed: wearthering Pisha sandstone, coal gangue, caliches used as a soil amendment material in the newly configurated soil can prevent the soil infiltrated to the below layer. The cumulative infiltration and saturated hydraulic conductivity reached the minimum in the Pisha sandstone in the middle layer in the loessial or the sandy soils.Water infiltration can be described well by the Kostiakov infiltration model, and when the wearthering Pisha sandstone in the middle layered position can well prenend the infiltration than in other soil layer position. The infiltration process of the sandy soil or the loessial soil containing caliches and coal gangue can be described by Kostiakov infiltration model very well. The wetting front changed with time can be described well by powed function. The presence of the two kinds of rock fragment with the wearthing Pisha sandstone in the soil impended infiltration than those of not rockfragment and wearthing Pisha sandstone presenced soil. The cumulative infiltration, wetting front andthe saturated hydraulic conductivity firstly increased with the increase of rockfragment and the decrease of pisha sandstone, then the cumulative infiltration, wetting front and saturated hydraulic and conductivity decreased, at last the cumulative infiltration, wetting front and saturated hydraulic and conductivity increased with the increase of rockfragment and the decrease of pisha sandstone. The wetting front, the cumulative infiltration and the saturated hydraulic conductivity reached the minimum in the pisha sandstone and the rockfragment soil with the height ratio of 1:3.3. Improvement coal mine area by wearthering Pisha sandstone study in the soil column experiment showed: wearthing Pisha sandstone as the material of mine reclamation, added Pisha sandstone in the sandy soil, loessial soil and irrigated-silt soil increase the water holding capacity. As the increase of added wearthering Pisha sandstone, the saturated water content increased in the improvement soil. The cumulative infiltration and wetting front firstly decreased with the increase of wearthering Pisha sandstone increase, and then increase with the increaseof wearthering Pisha sandstone increase. The cumulative infiltration and wetting front showed a correlative linear relationship. Both cumulative infiltration and wetting fronting were lowest in wearthering Pisha sandstone mixed with sandy soil or the loessial soil in the 1:3 treatments. Saturated hydraulic condutivity were also lowest in the 1:3 treatments in the wearthering Pisha sandstone mixed with sandy soil, loessial soil and the irrigaitong silt soils. The Kostiakov infiltration model and the Philip infiltration model described the infiltration processes and the wetting front changed with time can be described by the Pisha sandstone mixed with the sandy soil, loessial soil and irrigation silt soils.4. Grow ryegrass in the plot showed: The soil nutrient, the shoot nutrient after three time cutting and root nutrient was higher in the sandy soil mixed with rockfragment(coal gangue,caliches) treatment than other treatment in the homogeneous filling ways. The soil nutrient,the shoot nutrient after three time cutting and root nutrient has no significant difference. In the layered soil filling ways, the waerthering Pisha sandstone mixed in the middle layer with sandy soil treatment and the wearthering Pisha sandstone mixed in the middle layer with the sandy soil mixd with caliches treatment has higher soil nutrient, the shoot nutrient after three time cutting and root nutrient than in other treatment. Soil nutrient in the middle layer was higher than in the upper and bottom layer. The soil nutrient, shoot and root nutrient in the same soil layer has no different significance. Enough water can increase the ryegrass shoot and root nutrient in the improvement soil, and enhanced the absorption of N, P, K nutrient of the regrass. In the water treatment, the shoot nutrient and root nutrient of ryegrass has significant different.5. Grow ryegrass in the plot showed: In the Homogeneous soil treatment, added thewearthering Pisha sandstone in the sandy soil obvious increase the ryegrass length, root area,root diameter and root density. The effect of different treatment was: sandy soil mixed with gangue, sandy soil mixed with caliches, sandy soil mixed with wearthering Pisha sandstone.The treatment sandy soil mixed with coal gangue has the higheat water use efficiency, but no significant different change in the loessial treatment. In the layered filling ways, the treatment in the sandy soil mixed with Pisha sandstone increase the ryegrass root biomass and total biomass, in the three soil layer, the root biomas and total biomass has significance different. The pisha sandstone in the middle mixed with coal gangue and the Pishan sandstone in the middle mixed with caliches has the highest ryegrass length, root area,root diameter and root density. And change a decrease from the upper layer to the bottom layer, but in the loessial layer has no significant difference.