The Effect Of Wormcast On The Forms Of Cd And As In Soil And Uptake Of Cd And As By Pakchoi

With the rapid development of global integration, containing heavy metal pollutants through various channels into the soil, the soil heavy metal pollution phenomenon common.The polluted by Cd and As the proportion of the largest, about contaminated accounted for about 40% of the arable land.Vegetables in some cities in north China, grain base has also been different levels of heavy metal pollution, crop quality and yield decreased,and it also can cause economic losses.Heavy metals in the soil can also be hazardous to human health through food chain, and will lead to further deterioration in the quality of air and water environment.In the wormcast contains large amount of humus, the main component of humus is humic acid.A large number of studies have indicated that humic acid itself is very strong adsorbent and can adsorb dissolved metals and affect the bioavailability of heavy metals.The large surface area of wormcast can increase the porosity of soil, and the adsorption capacity is stronger, so it can adsorb heavy metals to a great extent.In addition, because of the large surface area, many beneficial microorganisms can survive and have a good ability to absorb and maintain nutrients, which is conducive to the growth of crops.This topic research the Effect of Vermicompost on the morphology of As, Cd in the soil and uptake of Cd and As by pakchoi.For the wormcast repair Cd and As pollution soil to provide theory basis.Tt also has a positive guiding significance on pakchoi production,and it also will to improve the quality of people's living environment has a wide range of practical significance.The main results and conclusions are as follows:Wormcas can decrease the amount of dissolved and exchangeable, carbonate and oxidation state in the soil and increase content of organic combined state and residual state Cd and As; With the increase of wormcast adding,amount of dissolved and exchange state,carbonate state and the content of oxidation state gradually low, than did not add theprocessing of wormcast content, organic combination of state and residual state content increased, add wormcast processing content were higher than not, the result shows that the wormcast can better weaken the mobility and bioavailability of Cd and As, reduce the Cd, As the biological toxicity.Earthworm manure on soil enzyme activity test results show that: the influence of Cd and As in soil urease and acid phosphatase has obvious inhibitory effect. After adding wormcast, improve soil urease activity and acid phosphatase activity.The total amount of Cd and As in soil increased with the addition of wormcast in soil.But the contents of As and Cd in pakchoi showed a decreasing trend.Add the wormcast can inhibit the absorption of pakchoi on Cd and As,thus Reducing the Cd and As the content in pakchoi.