土壤中可溶性有机氮含量及其影响因素研究

Contents of Soluble Organic Nitrogen in Soil and Its Influencing Factors

研究了农田和日光温室2个生态系统土壤中可溶性有机氮（SON）的含量及施肥和栽培模式对其含量的影响。结果表明，农田和日光温室土壤中SON的含量平均分别为39．19mg kg^-1和320．16mg kg^-1，分别占可溶性总氮（TSN）的80％和73％，说明SON是土壤氮素中不可忽视的氮索组分。不同栽培模式对土壤中SON的含量及其占TSN的比例的影响因生育时期的不同而异。覆草显著增加了小麦拔节期0～5cm土层土壤中SON的含量，覆膜各土层SON含量均较常规模式有所提高；开花期覆草和覆膜模式土壤中TSN和SON含量较拨节期的显著下降。施用无机氮肥对土壤中SON的含量无显著影响。

The contents of soluble organic nitrogen （SON） in soils of foreland and sun - light greenhouse as well as the effects of nitrogen fertilizr and different cultivation ways on SON contents in the arable soils were studied. The results showed that the contents of SON in the soils of farmland and greenhouse were 44.60 mg kg^-1 and 320.16 mg kg^-1, respectively,attainting for 79.27% and 73.23% of the total soluble nitwgen （TSN）, respectively, This indicated that the SON was an important component of nitrogen in the soils. The effects of nitrogen fertilizer and different cultivation types on the contents of SON in the arable soils varied with the growth period of wheat. Straw mulching significantly increased the SON in 0 - 5cm layer of soil at the jointing stage of wheat. Compared with the conventional cultivation method, the plastic film mulching increased the content of SON in the 0-20 cm soil layer. For the treatments mulched with straw or plastic film, the contents of TSN and SON decreased from the jointing stage to the anthesis stage. The application of nitrogen fertilizer had no significant effect on the content of SON in the soil.