Research On Soil Water And Salt Movement Of Drip Irrigation Under Different Plastic Mulch In Cotton Field

Drip irrigation under plastic mulch technology has been a large area of application in the arid andsemi-arid region of China since1996, this provides important technical support for water saving irrigationagriculture to increase production. However, along with the extending length of drip irrigation under plasticmulch plant, the film drip irrigation of farmland soil salt content has a tendency to increase gradually. Howto achieve balance of salt in drip irrigation under plastic mulch of farmland, and prevent the occurrence ofsecondary salinization of soil are problems to be solved now. This study is based on Fukang desertecosystem national field station of Chinese Academy of Sciences to solve soil salification problems of dripirrigation under plastic mulch.combined the field experiment and simulation method, Studied water and saltmovmen of drip irrigation under plastic mulch under three different plastic mulch (three mulch wide, threeiner-mulch distance, three inter-mulch treatment). The main conclusions are as follows:(1) In the three different plastic mulch width of40cm (narrow film),130cm (wide film), and220cm(ultra wide film) conditions, desalination order is narrow row in centre film of ultra film> narrow row ofwide film> narrow row of narrow film> narrow row of ultra film; salt lateral movment order is widefilm> narrow film> ultra wide film; salt accumulation rate in inter-mulch is wide film> narrow film>ultra wide film. At the end of the growing periods, Soil salt content order is inter-film> wide row> filmedge> narrow row> narrow row of centre in film. In the growing periods,0-20cm always desalination,80-100cm soil layer always salt accumulation, and20-80cm soil layer become salification in the august.Plastic mulch wide is wider, the soil temperature is higher. Plastic mulch enhanced soil temperature mainlyin cotton growth prophase.(2) In the three different inter-mulch (film wide is130cm) of20cm,60cm and100cm conditions,inter-film is smaller, the soil moisture content and soil temperature is higher. Soil moisture content isincreasing with soil depth, and decreased with extension of the growing season. In narrow row of dropper,desalination effect of inter-film20cm treatment is best, followed by inter-film60cm, iner-film100cm. Inwide row, salification effect of iner-film100cm is highest, followed by inter-film20cm, inter-film60cm islowest. Lateral movment of salt of iner-film60cm is best. Soil salt content of iner-film all increasing withcotton growing season, and the accumulation of salt in the surface soil mainly at the early stage of thecotton grow.(3) Under the three different treatments in inter-film (inter-film ditch, inter-film level, inter-filmridging) conditions, soil moisture content highest is inter-film ditch treatment, followe as inter-film leveland inter-film ridging. In the narrow rows, desalting of inter-film ridging is best, followed by level andditch. The salt lateral movment effect of inter-film ridging is better inter-film level, inter-film dicthtreatment is the worst. Soil temperature the highest is inter-film ridging treatment, followed by inter-film,inter-film treatment soil temperature is the lowest.(4) Through the analysis of soil temperature, soil moisture content, soil salt content and cotton output,under the condition of the soil salt content low, we can choose film width130cm and inter-film60cmplanting patterns. Under the condition of the soil salinity is high, we can choose film width130cm,inter-film60cm and inter-film ridging planting patterns.(5) Using HYDRUS-3D software can be a very good simulation of soil water and salt movementcharacteristics under different plastic mulch.