两种氮肥不同用量及添加双氰胺对蔬菜品质和土壤氮形态的影响

采用网室盆栽结合田间小区试验,研究了两种氮肥(尿素和硝酸铵)不同用量及其添加双氰胺对土壤铵态氮、硝态氮、土壤硝化细菌动态变化的影响,以及与空心菜、菠菜中硝酸盐、产量和品质关系。结果表明,2种氮肥不同用量都与空心菜的产量呈显著或极显著的二次曲线关系,与土壤铵态氮和硝态氮、以及蔬菜中硝酸盐含量呈正相关。不论施用尿素还是硝酸铵的处理,添加双氰胺都有利于提高蔬菜产量和维生素C、降低土壤中硝化细菌数量、减缓铵态氮的转化,从而减少蔬菜对硝酸盐的吸收。不论是减少土壤硝化细菌数量、减少土壤硝态氮含量、增加土壤铵态氮含量,还是减少菜体硝酸盐含量的效果上来看,在尿素中添加双氰胺处理的效果均好于在硝酸铵中添加双氰胺的处理,证实了双氰胺作为一种硝化抑制剂,能有效抑制硝化细菌数量,从而降低土壤硝态氮含量,最终导致降低菜体硝酸盐含量。

Effects of Different Dosage of Two Nitrogenous Fertilizers and Dicyandiamide on Vegetable Quality and Soil N Form

Hyocaust and field plot experiments were carried out to study effects of different dosage of two nitrogenous fertilizers and dicyandiamide(DCD) on the kinesis of NH4+-N,NO3--N and nitrobacteria on soil,as well as the relationship with the amount of nitrate,yield and quality of swamp cabbage and spinach.Results indicated that the relation between different dosage of two N fertilizers and yields of swamp cabbage was significant and taking on the curve of second order,while the correlations of dosage of N fert...