氮镉互作下双氰胺对小白菜地尿素转化及土壤酶活性的影响

Effect of Dicyandiamide on Urea Transformation and Soil Enzyme Activities Under Cadmium Interaction Nitrogen in Brassia chinensis Field

以"上海青"小白菜为试材,采用盆栽方法,研究了氮(0.2g·kg-1土)、镉(2.0mg·kg-1土)互作条件下,添加硝化抑制剂双氰胺(DCD,为纯氮的5%、10%、20%分别为处理1、2、3)对小白菜地土壤中NH_4^+-N、NO_3^--N、有效镉转化以及土壤酶活性的影响。结果表明:在试验范围内,添加DCD能显著降低土壤NO_3^--N的累积量,分别降低42.23%、98.45%,DCD施入量为纯氮的20%时土壤中NO_3^--N未检出;且施入双氰胺的量与NH_4^+-N的转化量、NO_3^--N的转化量呈极显著的正相关和负相关,相关系数分别为0.998、0.993。同时,能够显著影响土壤脲酶活性、蛋白酶活性、蔗糖酶活性、酸性磷酸酶活性和土壤有效镉的转化,且土壤脲酶活性与土壤有效镉之间存在极显著相关性,相关系数达0.999,土壤蛋白酶活性、蔗糖酶活性以及土壤酸性磷酸酶活性在不同处理下均有不同程度的变化,与对照相比,处理1与处理3显著提高了土壤蛋白酶及蔗糖酶活性,3个处理均显著提高酸性磷酸酶活性。这说明氮镉交互作用下,添加双氰胺能显著降低土壤NO_3^--N的累积量、显著提高土壤酶活性,可以作为试验范围内菜地土壤系统的有效改良材料。

‘Shanghai Green＇Chinese cabbage was used as test material,using pot experiment,the effect of addition of nitrification inhibitor DCD（for pure nitrogen 5%,10%,20%;named treatment 1,2,3,respectively）on pakchoi soil NH4^＋-N and NO3^--N and available cadmium transformation and soil enzyme activity under nitrogen（0.2g·kg^-1 soil）Cd（2.0mg·kg^-1 soil）interaction conditions were studied.The results showed that within the test range,adding DCD could significantly reduce soil NO3^--N accumulation amount and decreased 42.23% and 98.45%,respectively,DCD was applied to an amount of 20% pure nitrogen in the soil NO3^--N was not detected;and dicyandiamide was applied to the amount of the conversion of the amount of NH4^＋-N,NO3^--N amount of conversion into a very significant positive correlation and negative correlation coefficients were 0.998,0.993.At the same time,could significantly affect soil urease activity,protease activity,invertase activity,acid phosphatase activity and soil available Cd conversion,and between the enzyme activity and soil available Cd urease significantly,the correlation coefficient of 0.999 and soil protease activity,invertase activity,and soil acid phosphatase activity in varying degrees of change under different treatment compared with the control,treatment and treatment 1,3significantly increased soil protease and invertase activity,three treatments significantly increased acid phosphatase activity.The results showed that the interactive effects of nitrogen application and cadmium,add dicyandiamide could significantly reduce soil NO3^--N accumulation and significantly improve the soil enzyme activity and could be used as a test range in vegetable soil system improvement and effective.