稻田土壤氮矿化速率的研究

STUDY ON MINERALIZATION RATE OF NITROGEN IN PADDY SOILS

稻田土壤氮在淹水密闭培养12周内的矿化累积曲线采用预培期计算法(包括干土效应)的有效积温式精度明显优于扣除预培期计算法(扣除干土效应)。用预培期计算法求得的矿化参数K>0.0<n<1。矿化速率是土壤氮矿化过程的特征值,有效积温105℃时的矿化速率(Y_(105)~′)与土壤氮矿化能力及矿化氮有效性均密切相关。稻田晚发性取决于土壤氮后期的矿化速率,有效积温840℃时的矿化速率(Y_(840)~′)愈大,后四周矿化量愈多,晚发性愈强。

The study carried out By the submerged incubation method and field experiments showed that the mineralization rate could be used as a characteristic value O nitrogen mineralization in paddy soils. The results obtained are summarized as follows:1. Effective accumulated temperature empirical model (Y=K[(T-T_0)D]~n) obtained without deducting the dried soil effect during 12-week incubation period was better than that with deducting the dried soil effect. The empirical model without deducting dried soil effect had a higher precision, and its mineralization parameter K>0 and 0<n<1.2. The mineralization rate Y'(Y'=Kn,[(T-T_0)D]^(n-1)) might be the characteristic value of nitrogen mineralization. A highly positive correlation existed between the mineralization rate at effective accumulated temperature of 105℃ (Y'_(105)) and mineralization power, and Y'_(105) was closely negatively related to the availability of mineralized N. The amount of N mineralized during the last 4-weeks incubation period (effective accumulated temperature of 840 1260℃) was determined by Y'_(840).The higher the Y'_(840), the more the N was mineralized in the late period.