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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。
Using “Shanghai Green” cabbage as test material, pot experiments were conducted to study the effects of nitrogen (0.2g · kg-1 soil) and cadmium (2.0mg · kg-1 soil) Cyanamid (DCD, 5%, 10%, 20% of pure nitrogen treatments 1, 2 and 3, respectively) was used to test the effects of NH 4 + -N, NO 3 - Effect of activity. The results showed that the addition of DCD could significantly reduce the accumulation of NO_3 ~ --N in the soil and decrease the contents of NO_3 ~ -N by 42.23% and 98.45%, respectively. When the DCD application was 20% The amount of dicyandiamide applied was significantly positively and negatively correlated with the conversion of NH_4 ~ + -N and the conversion of NO_3 ~ - N, the correlation coefficients were 0.998 and 0.993, respectively. At the same time, soil urease activity, protease activity, invertase activity, acid phosphatase activity and soil available cadmium conversion were significantly affected, and there was a significant correlation between soil urease activity and soil available cadmium with a correlation coefficient of 0.999. Soil protease Activity, invertase activity and acid phosphatase activity of soil had different degrees of change under different treatments. Compared with the control, treatment 1 and treatment 3 significantly increased soil protease and invertase activity, and the three treatments significantly increased the content of acid phosphatase Enzyme activity. This indicates that the addition of dicyandiamide under nitrogen and cadmium interaction can significantly reduce the accumulation of NO_3 ~ - N in soil and significantly increase the activity of soil enzymes, which can be used as an effective improvement material for soil systems in the vegetable field in the experimental range.