杨凌地区大棚土壤硝态氮累积效应研究

通过调查不同棚龄大棚土壤硝态氮含量的变化,研究了杨凌大棚蔬菜生产中的土壤硝态氮累积特性,结果显示:大棚蔬菜土壤硝态氮含量显著高于露天菜地和拱棚土壤,反映出过高的氮肥投入,各棚龄土壤均表现出明显的硝态氮表土累积。随着棚龄的增加土壤硝态氮及总盐含量呈增加趋势,土壤pH值则表现为逐渐下降,不合理的施肥将导致短龄大棚土壤硝态氮及总盐含量急剧上升而超过长龄大棚土壤;在番茄生长周期内随生育期延长硝态氮在土壤中累积量逐渐增大,但总盐含量变化并不明显。硝态氮在土壤中的迁移,导致土壤底层硝态氮也大量累积。

Effect of Nitric Nitrogen on Different Greenhouse Soil in Yangling Area

This paper analyses nitric nitrogen of the greenhouse soil in different service life in Yangling.The result indicated that the content of nitric nitrogen in greenhouse obviously higher than the open crop field,the salt and nitric nitrogen accumulation was obviously on top greenhouse soil,the content of nitric nitrogen trend to increased along with cultivated year.The pH value was dropped by cultivated year;the content of pH was higher in upper layer than in lower layer.There is a significant negative interrelation between pH value and nitric nitrogen,r=0.942 3.The content of nitric nitrogen changed in different growing period,the nitric nitrogen contents begin to decrease after tomato fruit stage,the nitrogen accumulates does not have a notable relation with the general salt and pH during the whole growth period.