一种直接测定硝化—反硝化气体的15N示踪—质谱法

本文对¹⁵N示踪—质谱法的可靠性进行了检验。结果表明,在不同的¹⁵N丰度气体样品的测定中,用两种方法(反硝化作用源的¹⁵N丰度法和气样的¹⁵N丰度法)计得的反硝化损失量基本一致,故建立起来的¹⁵N示踪—质谱法是可靠的。该方法的测定偏差随气样¹⁵N丰度的降低而增大。此外,回收率结果表明,(N₂+N₂O+NO_x)-¹⁵N累积释放量占加入NO₃-¹⁵N量的94.1％。因此,这一方法可用于直接测定氮肥的硝化—反硝化损失的研究中。

A METHOD FOR DIRECT MEASUREMENT OF 15N-GASES FROM NITRIFICATION-DENITRIFICATION WITH MASS SPECTROMETER

Reliability of the method developed in the laboratory for direct measurement of (N₂+N₂O+NO_x)-¹⁵N from nitrification-denitrification was examined in the present paper. The results showed that the amount of (N₂2+N₂O+NO_x)-¹⁵N produced thuough denitrification of added ¹⁵N-nitrate by the two methods (¹⁵N enrichment of the NO₃-N pool undergoing denitrification, and ¹⁵N enrichment of the gas samples) were measured accurately; the recovery of added ¹⁵N-nitrate as (N₂+N₂O+NO_x)-¹⁵N from denitrification was up to 94. 1% in the flooded incubation experiment. The error of the method was increased with decrease in ¹⁵N enrichment of gas samples. It is concluded that the method is reliably. Therefore, investigation on nitrification-denitrification loss of fertilizer nitrogen can be done by using the method.