The Response Mechanism Of Stress Of Soil Salinizationon Apple Tree In Arid Region

Soil salinity had been considered the most important obstacle of agriculture production in Arid Region, Semi- Arid Region and Intensive Irrigated Area. The matter transferring (salt) and cumulating rule of soil under farming environment in Arid Region was the hotspot problem of soil science research in this years. The purpose of this project was to research orchard soil in Middle East Region (Qin'an County) of Gansu province in Arid Region of North-West of China, and to find out the main problem of formation soil salinity, the grade of soil salinity and salinity distribution. we analyzed the change character of salt in soil profile on time and spatial and discussed the cumulating rule of salinity in apple tree tissue. The results are as follows:1. We analyzed the cause of formation soil salinity in the research area and the main cause of soil accumulate salinity was included climate drought, deficit of water resource and use high mineralize water (1.85-2.82g/L) irrigating. Therefore, soil salinization mainly distributing on irrigate area of plain and in the middle hillside. The relative between tolerance extent and irrigating times was good. The regulation of distribution was random and occupied 3740hm~2 farm land―mostly of them was orchard, which was 22.48% in total orchard area.2. The basics character of soil profile salinization was showed as follow: the 0-40cm layer was the category of sulfate-chloride and salt content variance 0.058%-0.073%;the 40-80cm layer was the category of chloride-sulfate, salt content variance 0.073%-0.093%;the 80-120cm layer was the category sulfate, salt content variance 0.093%-0.117%.There were obvious relativity between the distribution character of soil profile salinity and ion trait and different ion have different extent to harm apple trees.3. Influence by environment and soil condition, the transfer and accumulation of soil profile salt ion generally could be divided four phases: salt basic stabilization period―from April to middle of May; salt speediness accumulating period―from middle of May to middle of June; combine accumulating salt and dropping salt period―from middle of June to last of July;, slow accumulating salt period―from later July. There has a very great variability of salt of the 0-40cm layer during apple growth. It was give priority to accumulate under 40cm...