Effect Of Several Nitrogenous And Potassium Fertilizers On Availabilities Of Plumbum And Cadmium In Plumbum Or Cadmium Polluted Soil

The influences of several nitrogenous and potassium fertilizers on the availabilities of Pb ,Cd in soils and the bioavailabilties of these heavy metals to rape, pakchoi and rice were evaluated with laboratory incubation and pot experiments. The effect of nitrogenous, phosphatic and potassium fertilizers on the bioavailabilities of Pb and Cd in the rhizosphere of the red soil were also investigated with pot experiment. The main results were shown as follows:1.The Cl- could distinctively restrain the transformation and nitrification of ammonium nitrogen under 60% field capacity in Pb or Cd polluted soils, but the capability of restraint would drop at a large degree under water flooding. Both presence of Cd and the condition of water flooding could restrain the transformation and nitrification of ammonium nitrogen evidently.2.Several nitrogenous fertilizers could decrease pH under 60% field capacity in Pb or Cd polluted soils. The capabilities in decreasing pH varied in following relationship:(NH4)2SO4SNH4Cl>Ca(NO3)2>CO(NH2)2>CK;but under water flooding the relationship was:NH4Cl> (NH4)2SO4>Ca(NO3)2>CK>CO(NH2)2. Under water flooding, the soil pH in several nitrogenous fertilizers treatments were higher than that under 60% field capacity.3.Applications of NH4Cl and (NH4)2SO4 both could higher the contents of water soluble Cd under two kinds of water contents of culture, but the application of Urea would lower it under water flooding. It was uniform that the effect of several nitrogenous fertilizers on the contents of available Pb or available Cd. The capabilities of several nitrogenous fertilizers for increasing the contents of available Pb or Cd under 60% field capacity was in this relationship:NH4Cl>(NH4)2SO4>CO(NH2)2>CK > Ca(NO3)2, but under water flooding that was:NH4Cl>(NH4)2SO4>CK = Ca(NO3)2>CO(NH2)2. The contents of available Pb or Cd under water flooding were lower than that under 60% field capacity.4.The results of correlation analysis indicated that the pH of several nitrogenous fertilizers treatments was distinctive negative correlated with the contents of water soluble Cd, available Pb and Cd under two kinds of water contents of culture. Several nitrogenous fertilizers could largely affect the availability of heavey metal by changing the pH of soil, which was one of the principle that how it affected the availability of heavy metal.5.Application of KC1 always increased the content of water soluble Cd, butApplication of KNO3 markedly reduced it under 60%field capacity. It would increased the content of water soluble Cd all the time under water flooding when K2SO4 and KC1 were applied. The contents of water soluble Cd of several potassium treatments under water flooding were lower than that under 60% field capacity. Application of KC1 has distinctively promoted the content of available Cd but indistinctively among other treatments after two months later under two kinds of water contents of culture. All the potassium fertilizers could reduce the availability of Pb distinctively but indistinctively among potassium fertilizers varieties.6.The capabilities of several nitrogenous fertilizers for promoting uptaking and accumulating Pb in rape, pkochio and rice varied in this relationship: NH4Cl> (NH4)2SO4>CO(NH2)2>Ca(NO3)2.The capabilities of several nitrogenous fertilizers for promoting uptaking and accumulating Cd in rape and pkochio varied in this relationship: NH4Cl>(NH4)2SO4>CO(NH2)2>Ca(NO3)2. Not only can ensure rice yield but also effectively reduce the Cd toxicity by application of urea in Cd polluted soil.7.Application of KNO3 could largely decrease the contents and cumulant of Cd in rape, pakchoi and rice in soil contaminated by Cd.The highest biomass of rice and the lower contents of Cd were found with application of K2SO4. It is indistinctive that the effect of several potassium fertilizers varieties on bioavailability of Pb.8.The availabilities of Pb and Cd in rhizosphere of red soil would drop with adding phosphatic fertilizer. All the contents of available Pb in red soil rhizosphere w...