Study On Salinization Effect Of Silt Dam Construction In Chakou Small Watershed

Soil salinization will cause soil consolidation,fertility decline,hindering the absorption of nutrients by crops,seriously affecting the normal growth of crops.In recent years,the problem of soil salinization in Chakou small watershed has become increasingly prominent,which poses a threat to food yield and ecological security in the watershed.In this paper,according to the characteristics of each ditch warping dam in the basin,the surface runoff of each warping dam is simulated by using Ann AGNPS model,and 24 warping dams are selected for soil sample collection combined with remote sensing images.The sampling depths are 0-5cm,5-10 cm and 10-20 cm,respectively.In this paper,the characteristics and influencing factors of soil salinization of warping dam in the study area were analyzed by using Arc GIS,Excel,SPSS software and Ann AGNPS model,and the corresponding control measures were put forward.The results show that:(1)the soil salinization of warping dam in the study area is light,and the soil belongs to non-saline soil and mild saline soil,among which the salt content of warping dam in Xinshenggou,Muguagou and Xiyu ditch is the highest.And the degree of salinization decreases with the deepening of soil layer.In terms of alkalinity,there are more lightly alkalized soils,moderately alkalized soils,followed by strongly alkalized soils,and a few non-alkalized soils.The maximum alkalinity of soil is 14.67% and the minimum is 7.06%.The difference of alkalinity of each soil layer in each warping dam is small.(2)in the study area,the salt content in front of the warping dam is larger than that behind the dam,among which the difference between the front and back of the warping dam in Xinshenggou is the biggest.In terms of alkalinity,on the whole,the soil alkalinity in front of the warping dam is less than that in the back of the dam,and the difference between the front and back of the dam is the greatest.It was 8.73%.(3)the analysis of influencing factors showed that there was a significant or very significant positive correlation between available nitrogen,available potassium,cumulative water sink and soil salt content(p < 0.01).There was a significant negative correlation between soil p H value and soil salt content(p < 0.01).In addition,the drainage ditch will affect the salt content in front of the dam,the salt content in front of the dam is greater than that in the back of the dam,and the salt in front of the dam is larger than that in the back of the dam,and the salt content in front of the dam is less than that in the back of the dam.From the point of view of alkaline influencing factors,electrical conductivity,available nitrogen,available phosphorus,available potassium,clay and soil alkalinity were significantly or very significantly negatively correlated(p<0.01),and positively correlated with silt(p<0.01).From the point of view of alkaline factors,there was a significant or extremely significant negative correlation between electrical conductivity,available nitrogen,available phosphorus,available potassium,clay and soil alkalinity(p < 0.01).There was a significant positive correlation between soil alkalinity and silt(p < 0.05);(4)in the treatment of salt,According to the specific conditions of each warping dam to establish,improve,clean up the drainage system,in addition,the use of straw,plastic film mulching and other methods,as well as the combination of flood diversion and soil pressure salt to improve the saline soil of the basin.In the aspect of alkali control,organic fertilizer,gypsum,soil replacement pressure alkali,cushion pressure alkali and other methods can be used to reduce the content of soil alkali,so that the alkaline soil in the study area can be effectively improved.