土壤中非代换铵的行为Ⅱ.非代换铵含量与其它形态氮素的关系

研究了西北地区24种、杨陵区12种农田土壤中的非代换铵含量与土壤其它形态氮素的关系。结果表明,土壤中的非代换铵与全氮的密切关系仅是一种表观现象,原因在于全氮包括非代换铵这一因子,扩大了相关系数。如用有机氮计算,这种关系随之消失。非代换铵与HN_4~+-N及NO_3~-N等矿质氮无关;不管从静态或动态考察,都未能发现它们之间有平衡关系。培养后的可矿化氮与非代换铵无本质联系,而碱解氮却与其显著相关。造成后一现象的原因在于碱解过程中有部分非代换铵释放出来,数量取决于原土壤中的非代换铵含量。

The Behaviour of Non-exchangeableAmmonium in Soils II.The relationship between non-exchangeable ammonium and other N forms

The relationships between non-exchangeable ammonium and other N forms were investigated using 24 soils sampled from Northwest China and 12. soils from Yangling, The results obtained show that the close correlation between non-^exchanangeable ammonium and total N was not true but only apparent situation. The reason is that the non-exchangeable ammonium was a part of the total N. When apart and the whole were used to calculate their relationship, the correlation coefficients would be increased. If, however, organic N was used instead of total N, the close relationship disappeared. The non-exchangeable ammonium correlated neither with organic N nor with mineral N, including NH4+-N and NO3"-N. Viewed from either static or dynamic situations, the equilibria amongst non-exchangeable ammonium, exchangeable ammonium and nitrate were hardly found. Also, there was no correlation between mineralized N obtained by incubation methods and non-exchangeable ammonium. However, the released N by NaOH-hydrolysis was well correlated with non-exchangeable ammonium, which was caused by the release of non-exchangeable N during the NaOH-hydrolysis and the amounts of which were determined by non-exchangeable ammonium contents.