Study On Regulating Function Of Compound Soil Coordination For Vegetative Establish In Ming Area

The moisture and nutrients of soil are the main limiting factor for vegetation restoration in arid and semi arid aeolian sand area due to lack of rainfall, bad sand soil texture led to leakage of water and fertilizer, and lower nutrition in soil. In this paper, the texture character, fertilizer and water holding performance of the soil as well as the possibility of new texture traits to soil water holding and fertilizer retention characteristics were studied by investigation of precipitation and soil characteristics in Maowusu Desert aeolian sand area, with laboratory simulation and field experiments to trace the loess and sand mining area of aeolian sandy soil in different proportions. Hedysarum mongolicum Turcz. photosynthesis and physiological resistance were researched by combination of soil coordination, adding nitrogen fertilizer (CO (NH2) 2), plant growth regulator (PP333), precipitation and other factors for selection of the optimal mixture ratio of soil coordination and optimal factor level combination.(1) Soil particles of 89.69% in 0-100cm depth excavation were sand particles, and the texture of sand was sand soil. The contents of underground loess silt and clay content were 74.46%, texture was silt loam, and particle composition and texture traits existed complementary. The pH value of aeolian sandy soil and trace underground loess were alkaline, the contents of organic matter, total nitrogen, phosphorus and available nitrogen and phosphorus nutrient were extremely low, and the contents of total potassium and available potassium were abundant.(2) The types of compound soil were sand, loamy sand, sandy loam, loam and silt loam with increase of the ratio of loess in the mixture of aeolian sandy soil and covered underground loess mixed. The particle gradation was benign, bulk density decreased, capillary porosity increased, and water holding fertilizer performance gradually enhanced. The spatial variability of compound soil bulk density, capillary porosity, water capacity, protecting fertilizer performance were almost controlled by the proportion of loess.(3) The activities of Pn,Tr, Gs, Ci, qP, ETR, Fv/Fm, OPS Ⅱ, POD, SOD and CAT in Hedysarum mongolicum Turcz., and contents of Chla, Chlb and Chltwith first increased and then decreased with the increase of the loess proportion and precipitation under interaction of soil coordination and precipitation. The change trend of WUE, qN, Pro, MDA, REC and Chla/Chlb were opposite. The most favorable comprehensive physiological function of soil coordination and rainfall were that the proportion of loess in compound soils was 25%, and the rainfall in plant growth season from April to September was 155-233mm.(4) The activities of Pn,Tr, Gs, Ci, qP, ETR, Fv/Fm, ΦPSⅡ, POD, SOD and CAT in Hedysarum mongolicum Turcz., and contents of Chla, Chlb and Chit with first increased and then decreased with under interaction of soil coordination and adding nitrogen. The change trend of WUE, qN, Pro, MDA, REC and Chla/Chlb were opposite. The most favorable comprehensive physiological function of soil coordination and adding nitrogen were that the proportion of loess in compound soils was 25%-50%, and nitrogen level was 120kg/hm2(5) The activities of Pn,Tr, Gs, Ci, qP, ETR, Fv/Fm, ΦPSⅡ, POD, SOD and CAT in Hedysarum mongolicum Turcz., and contents of Chla, Chlb and Chlt with first increased and then decreased with under interaction of soil coordination and plant growth regulator PP333. The change trend of WUE, qN and Chla/Chlb were opposite, while the contents of Pro, MDA and REC increased with the increases of the proportion of loess and PP333 concentration. The most favorable comprehensive physiological function of soil coordination and PP333 were that the proportion of loess in compound soils was 25%, and PP333 concentration was 50-100mg/L.(6) The effects of the interaction of soil coordination, nitrogen, precipitation and PP333 on photosynthesis and physiological resistance of Hedysarum mongolicum Turcz. were differences in response to the changes of various factors, and the effects of soil coordination and nitrogen fertilizer is more obvious. The favorable synthetic effects of photosynthesis and physiological resistance under four factors were 25% soil coordination, 50mg/L PP333, no nitrogen fertilizer and 387.5mm precipitation in 4-9 month, and 25% soil coordination, 100mg/L PP333,360kg/hm2 nitrogen fertilizer and 155 mm precipitation in 4-9 month.