不同园龄果园土壤腐殖质组分数量及其元素组成特征1）

摘要

以长期冻融条件下的典型中国北方果园土壤为研究对象，分析了不同园龄果园土壤腐殖质的结合态组分数量及其元素组成。结果表明：重组有机碳、松结态、稳结态腐殖质质量分数均逐年增加；紧结态腐殖质质量分数逐年减小。土壤重组有机碳、松结态腐殖质质量分数60 a间分别增加了11．59％、95．15％；果园土壤松/紧比逐年增大，种植60 a年均增长2．09％。近果园荒地土壤腐殖质以紧结态为主，占49．63％，种植60 a时果园土壤腐殖质结合形态以松结态和紧结态为主，分别为41．43％、38．50％；种植果树后，松结态、稳结态比例逐年上升，而紧结态比例逐年下降，松结态腐殖质相对质量分数上升了17．74％，紧结态腐殖质相对质量分数下降了11．13％。果园土壤松结态、稳结态胡敏酸（HA）、富里酸（FA）质量分数及其w（胡敏酸）/w（富里酸）均随种植年限逐年上升。种植果树60 a后，土壤松结态HA、FA质量分数分别增加了131．76％、66．67％。 FA、HA中N、C质量分数逐年上升，H、O质量分数则呈下降趋势；FA、HA中N与C原子数量比均逐年上升且大于近果园荒地；H与C、O与C原子数量比均逐年下降且小于近果园荒地；HA中H与O原子数量比果园土壤均大于近果园荒地。果园土壤稳结态腐殖质HA中的N、C和H元素质量分数均大于FA；HA中O元素质量分数小于FA中O元素质量分数。 FA、HA中N与C、H与O原子数量比均大于近果园荒地土壤，H与C、O与C原子数量比均小于近果园荒地。%We analyzed the effect of elemental composition and combined humus of typical orchard soils with different cultivation years in northern China under long-term freezing-thawing conditions.The content of the heavy fraction organic carbon, the loosely combined humus, the stably combined humus are increased with the cultivation year, and the tight combined humus is gradually decreased .The content of the heavy fraction organic carbon and the loosely combined humus annual growth rates are 11.59%and 95.15%in 60 years, respectively.The ratio of loosely and tightly in the orchards soil shows annual increasing trend by 2.09%.On uncultivated area near the orchard, the tight combined humus is main part about 49.63%, the loosely combined humus and the tight combined humus are main parts in the orchards soil, and respectively 11.59%and 95.15%in the 60th year.After the planting of fruit trees, the relative content of the loosely combined humus are in-creased by about 17.74%with the cultivation year, and the relative content of the tight combined humus is gradually de-creased by about 11.13%.The contents of the loosely combined humus acid (HA), the loosely combined fulvic acid (FA) annual growth rates are 131.76% and 66.67% in 60 years, respectively.On elemental composition the loosely combined humus, the contents of nitrogen (N) and carbon(C) are increased with the cultivation year, and hydrogen (H) and oxygen (O) are gradually decreased.N/C is increased and it is higher than that in wasteland soil, and H/C and O/C was opposite.H/O of HA is higher than that in uncultivated area near the orchard.On the stably combined humus in or-chard soil, the contents order of N, C, N is HA>FA, and that of O is HA