Study On Key Technologies Of Ecological Restoration For Erosion Gully In The Eco-fragile Area Of Black Soil

With increasing development,the problem of soil erosion has been paid wide attention,especially the occurrence and harm of erosion gullies,in black soil area,China.In recent years,the state has invested tremendous manpower and material resources in control engineering of erosion gully,but the basic research of erosion gully control is relatively rare.Especially for the eco-fragile areas in the northwest of the black soil region,there is an urgent need for the research and development of basic theory and ecological restoration technologies.This paper researched the occurrence and development of erosion gully in eco-fragile area of black soil by means of data investigation,field monitoring,sampling and experiments.The main results and conclusions are as following:(1)The location of eco-fragile area of black soil lies in Fuxin in Northwest Liaoning,Baicheng in Northwest Jilin,Chifeng in Inner Mongolia,northern Tongliao and Xing'an League.The regional eco-vulnerability tends to deteriorate.The main driving factors include concentrated rainfall,single industrial type,hilly topography,drought and barren soil,low vegetation coverage and so on.(2)The erosion gullies were developed in slope farmland and barren hillside in the region,with 41 019 erosion gullies over 100 m,total length is up to33877.322 Km and total area 92092.78 ha.The control measures are single,the soil in the gullies is dry and barren,and the vegetation planting is difficult.The main problem of control engineering is that most check dams have been damaged after years.(3)The shape of check dam was changed from line to arch.The simulation analysis by ANSYS LS-DYNA and MIDAS GTS software and monitoring of similar field engineering showed that the improved check dam is beneficial to sediment deposition,vegetation restoration and stability of bank of erosion gully.(4)The physical properties of the soil in this region are not conducive to water storage and water conservation.With the increase of erosion,the soil texture tends to be coarse-grained and sandy.The total nitrogen content of the soil in erosion gully ranges from 0.039% to 0.257%,the phosphorus content from 0.071% to 0.177%,the potassium content from 0.4% to 1.75%,and the average organic matter level of the soil is about 4%,which is similar to that of the whole country.The nitrogen,phosphorus and potassium were deficient in soil,and the content of organic matter was moderate.The best way to water conservation is the compound of water retaining-agent and film mulching.Adding 40-160 mg/kg of nitrogen fertilizer,20-80 mg/kg of phosphorus fertilizer and 40-320 mg/kg of potassium fertilizer could obviously promote the growth of plants.over 320 mg/kg of nitrogen fertilizer,160 mg/kg of phosphorus fertilizer and 160 mg/kg of potassium fertilizer,the promotion effect is weakened,even has the opposite effect.