Trace Elements Of Agricultural Soils Of Zhejiang Province, The Northern Part Of Effective State And Impact Study Of The Factors

Ecological and environmental effect of elements in soil depends on their chemical forms. Chemical forms of elements in soil, especially the bioavailability of elements with strong activity, have direct and obvious relation to ecological effect. The availability of elements in soil is affected by many factors. Due to the influence of such factors as soil type, geomorphic features, type of land use, sandification and so on, changes will happen to the composition and concentration of soil solution, acid base reaction, oxidation reduction potential, organic content, salinity and total contents of elements in soil. As a result, they have important effect on the availability of elements. Studies on the relation of the availability of elements in soil to total contents of elements, organic matter and pH values and revealing the main controlling factors having effect on the availability of elements in soil are not only of important theoretic significance, but also of practical significance in the aspects of soil nutrition and fertilization, heavy metal pollution prevention and prediction and early warning of geochemical hazards. This thesis systematically analyzed total contents and available contents of eleven elements, pH values and organic contents obtained from the investigation in the availability of elements in the northern Zhejiang Province, and briefly discussed the geochemical characteristics of elements in the agricultural soil in the study area: as a whole, the soil was meta acid, the organic content was moderate ~ high, B and Mo were poor in most places of the northern Zhejiang Province and Cu and Zn were also poor in some places, and however, the available Mn was relatively abundant, and the bioavailability and environmental risk of Pb and Cd in soil were by far greater than those of As and Hg. Regression analyses on all the data and the data sorted by soil types showed that the available contents of trace nutrient elements and toxic elements in soil were affected by such factors as total contents of elements, organic matter, pH value, soil type and so on and at the same time, their relationship was more complicated when the soil types were different.