| In recent years, both the shortage and the pollution of water resources are deteriorating gradually. Therefore, the irrigation with sewage has become an important way to save water, which is widely used now. However, with the development of sewage irrigation, people are becoming more and more concerned about the effect of the minimum element in the sewage, especially the heavy metal ion on the crops and soil environment. Based on the researches both at home and abroad, the paper studied on the influence of heavy metal such as Cd,Hg,As,Pb on the field and crop's growth by means of field experiments on wheat and maize, the result shows that:First, the crop's production is in proportion to watering; also, the one using sewage is higher than that using fresh water, as a conclusion, appropriate sewage irrigation can improve the crop's growth.Secondly, the investigation on the heavy metal content inside crops shows that the number inner spring wheat are like the following, Pb> As> Cd>Hg, while the number is largest in root. As far as the maize is concerned, the corresponding order is that, Pb> As> Cd, Hg is too small to be taken into account. Besides that, there is much more heavy metal in the parts of flower,leaf and root than in the stem an seed.Third, the tests on the fields indicated that the heavy metal content decreased as the increasing in depth at soil, but varied not much. Heavy metal increased and Hg slightly decreased after irrigation. In addition, the content of Cd and Pb grows with the watering, while As is on the contrary. Moreover, the simulant experiments are performed indoors, which used heavy metal such as Cd, the discovery is listed below: The linear adsorbï¼model that can describe adsorbent characteristic of Cd in the soil; we used a mathematical simulate to describe the movement of Cd through the convectionï¼dispersion model(), the calculation conform to the mensuration, so it is a good method to describe the rule of Cd's movement in the soil. ...
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