A pot experiment was conducted to study the effects of different kinds and amount of nitrogen fertilizers on cultivating rape( Brassica chinensis Linn) growth and soil properties. Results showed that the treatment of calcium nitrate was the highest increasing yield compared with no fertilizer application. However,the effect of ammonium sulfate increasing yield was not obviously shown. Calcium nitrate could also increase soil pH greatly,and added Ca2 +ion played a dominant role in increasing the content of available cadmium in soil. Coated urea did not influence soil pH,but could greatly decrease the availability of cadmium compared with normal urea; Soil pH value of other treatments( especially DCD application) decreased,and the soil available Cd content increased in response to their soil acidification. Use of urea and ammonium sulfate could decrease the cadmium content in the root and aerial portion of rape compared with calcium nitrate,but the translocation factor had nothing to do with the kinds and amount of nitrogen fertilizers. The treatment with excessive application of urea got a higher soil pH than other doses.

为了探讨氮肥种类和用量对土壤无机氮及土壤有效态镉含量的影响,采用恒温培养的方法,研究不同尿素用量及硫酸铵、硝酸钙、控释尿素和双氰胺(硝化抑制剂,简称DCD)对土壤镉氮含量变化的影响差异.结果表明,高施氮量的尿素处理具有较高的铵态氮和硝态氮含量.DCD能明显抑制硫酸铵的硝化作用.控释尿素通过自身包膜的作用,减缓了尿素向铵态氮和硝态氮转化的趋势.氮素施入土壤后,在微生物的作用下,会发生水解反应和硝化反应,使土壤pH发生变化,从而使土壤中有效态镉含量升高或降低.