可矿化氮与各有机氮组分的关系

用通气培养法测定了6种肥力36个不同土层土壤的可矿化氮,用Bremner法测定了各有机氮组分,采用相关分析、多元回归分析和通径分析确定可矿化氮与各有机氮组分之间的关系。结果表明,酸解氮与可矿化氮有较密切的正相关关系。在酸解氮中,酸解未知态氮与可矿化氮不相关;而氨基酸态氮、铵态氮、氨基糖态氮的多少与可矿化氮相互平行,相关系数均较高,似乎对可矿化氮皆有贡献。但多元回归分析表明,氨基糖态氮在方程中不显著;逐步回归分析更肯定了这一结果。通径分析进一步表明氨基酸态氮和铵态氮对可矿化氮有很高的通径系数,表明了它们有着直接重大贡献,而氨基糖态氮直接通径系数甚低。这些结果说明,可矿化氮主要来自酸解氮,特别是氨基酸态氮和铵态氮,后两者是其产生的主要来源。

Relation of mineralizable N to organic N components

Six soils with different fertilities were sampled from 6 sites, each consisting of 6 layers, for studying the relation of mineralizable N to organic N components. The mineralizable N was estimated by aerobic incubation and the organic N components by Bremner's procedure. The results showed that the mineralized N was parallel to and very well correlated with the total acid hydrolyzable N. Among the hydrolyzable N, the amino acid N and ammonia N had a highly consistent correlation and were the significant variables in the multiple equations in relation to the mineralized N, showing their importance to the mineralizable N. Amino sugar N, on the other hand, had a relatively high correlation with the mineralized N, but was not significant in these equations. In contrast, the hydrolyzable unknown N had no such relations. Path analysis further indicated that the amino acid N and ammonia N had highly direct path coefficients to the mineralized N and made great contributions to the mineralized through the amino sugar N, but the amino sugar N had no such contributions though other components. Results obtained strongly suggested that the mineralized N was mainly from the hydrolyzable N, particularly the amino acid N and ammonia N, the latter two being the major sources for its production.