KCl煮沸法浸取石灰性土壤可矿化氮存在的问题及改进

用KCl煮沸法浸取石灰性土壤中的可矿化氮时,会造成氨态氮的挥发,浸取出的NH_4~+-N反而比不煮沸时为低。为了解决这一问题,进行了不同温度下的保温静置、水浴加热等处理,浸取出来的铵态氮均未显著增加。采取酸化KCl溶液后再进行煮沸,显著地提高了NH_4~+-N的浸出量,且浸出结果与作物吸氮量有密切的相关性。

The Problem of Extracting Potentially Mineralizable N in Calcareous Soil by Boiling KC1 and Its Improvement

Using boiling KC1 solution to extract mineralizable N from calcareous soil has led to serious loss of N by volatilization, and therefore the amounts of ammonium extracted were less than those without boiling. In order to solve the problem, keeping the extracting solution with soil at different temperatures in different times and heating the solution with soil on water-bath were tried. The results show that the ammonium extracted was not significantly increased. Acidification of the KC1 solution with HC1 and then boiling it with soil for one hour, the amounts of ammonium extracted were significantly increased, and the mineralizable N extracted was well correlated with N uptake by plants.