Study Of Chemical Forms Of The Zinc And Cadmium In The Soil And Its Affecting Factors By The Agriculture Utilization Of Lake Sediments

With the development of the agriculture and industry, a lot of pollutants (including heavy metal) drain into the rivers, lakes and seas. The water and sediments are polluted. Even people health is dangerous. It is hot now to research the utilization of lake sediments as resources. Also the utilization of lake sediments as resources is ultimate measure to settle the sediments. There is a lot of heavy metal such as cadmium, which is easy to pollute the soil, water, plants and animals, even gets into the man's body with foods, accumulates to the thousands times to the natural environments, results acute or chronic poisoning. Some heavy metal such as zinc, is nutritious element that is needed by the grow of plants, but is also poisonous to the plants if it is too much in the soils. The chemical forms of the heavy metal elements is of importance to their availability for the plants. So to research the chemical forms of the heavy metal elements is needed. Use some measures to adjust the environmental conditions to control the availability of the heavy metal elements to an extant is worthy to research when the sediments is used as resources. So it is also significant to research the reasons that effect the chemical forms distributions of the heavy metal elements.This paper discusses the chemical forms of the heavy metal zinc and cadmium in the soil by the agriculture utilization of lake sediments by the plot experiments of wheat and the effects of pH, C/N and texture grade of the soil to the chemical forms of the heavy metal zinc and cadmium in the soil by the pot experiments.The results of the research to zinc show that, by the plot experiments, the concentration of the total, exchargeable, carbonate, Fe-Mn Oxide combined, organic and residual forms of the zinc increase in the soil with different extant with the increase of the amount of the lake sediments after the wheat is planted and reaped. The exchargeable, carbonate, Fe-Mn Oxide combined, organic forms of the zinc increase more than other form. In the plant, the concentration of zinc is high in the root, middle in the stem and leaves and low in the seed. The production of seeds, the biomass of the seed, leaf and stem, and the amount of the zinc gotten by the wheat from the soil increase with the increase of the amount of the lake sediments. By the plot experiments, with the increase of pH, the concentration of the exchargeable form of zinc decreases, while the concentration of carbonate and Fe-Mn Oxide combined forms of zinc increase. When C/N decrease, the concentration of the exchargeable form of zinc increase while the concentration of the organic form of zinc decrease. In the clay the concentration of the exchargeable form of zinc is lowest, while the concentration of the carbonate, Fe-Mn Oxide combined, organic forms of the zinc is highest. In the plants, the concentration of zinc is high in the root, middle in the stem and leaves and low in the seed. So when we use less amount of sediments, adjust higher pH, C/N is 25∶1 and clay is used, the concentration of exchargeable form of zinc in soil is lowest.The results of the research to cadmium show that, by the plot experiments, the concentration of the total, exchargeable, carbonate, Fe-Mn Oxide combined, organic and residual forms of the cadmium increase in the soil with different extant with the increase of the amount of the lake sediments after the wheat is planted and reaped. The exchargeable, carbonate, Fe-Mn Oxide combined, organic forms of the cadmium increase more than other form. In the plant, the concentration of cadminm is high in the root, middle in the stem and leaves and low in the seed. The concentration of cadmium in wheat seeds does not exceed the standard. The production of seeds, the biomass of the seed, leaf and stem, and the amount of the cadmium gotten by the wheat from the soil increase with the increase of the amount of the lake sediments. By the plot experiments, with the increase of pH, the concentration of the exchargeable form of cadmium decreases, while the concentration of carbonate and Fe-Mn Oxide combined forms of cadmium increase. The concentration of the exchargeable form of cadmium is lower when C/N is 25∶1 than C/N is 20∶1 or 15∶1, while the concentration of the organic form of cadmium is higher. In the clay the concentration of the exchargeable form of cadmium is lowest. So when pH is higher, C/N is 25∶1 and clay is used, the concentration of the exchargeable form of cadmium is lowest in soil. These conditions can decrease the poisoning of cadmium in soil to plants to an extant. In plants, the concentration of cadmium is high in the root, middle in the stem and leaves, low in the seed, also increases with the increase of the amount of the lake sediments.