4种落叶松粗根碳氮磷含量及化学计量比的季节变化

Seasonal Variation of Content and Stoichiometric Ratio of Carbon,Nitrogen and Phosphorus in Coarse Roots of Four Larch Species

以立地条件、林龄及经营措施相同的日本落叶松、长白落叶松、兴安落叶松、华北落叶松4种落叶松为研究对象,分析粗根碳、氮、磷含量及化学计量比的季节变化.结果表明:季节变化对各项指标的影响明显,除华北落叶松粗根碳氮比、长白落叶松有机碳含量季节间差异不显著外,其他指标季节间均存在显著差异.夏、秋季粗根有机碳含量、全氮含量、碳磷比、氮磷比显著高于春季,全磷含量、碳氮比显著低于春季,但夏季与秋季各项指标间差异均不显著.4种落叶松种间对比显示,日本落叶松比其他3种落叶松的碳、氮、磷含量具有更大的变异系数和极差,说明季节变化对日本落叶松生长的影响最大;日本落叶松氮磷比高,表明氮元素限制对其生长的影响最小.建议抚育过程中,在生长旺季对落叶松林,特别是长白落叶松和华北落叶松林施用氮肥,以促进林分生长.

Based on four species of Larix with the same site condition,age and forest management regime(Larix kaempferi,Larix olgensis,Larix gmelinii,Larix principis-rupprechtii),the seasonal changes in carbon,nitrogen,and phosphorus content and stoichiometric ratio of coarse roots were studied.The results showed that seasonal changes had a significant impact on the indicators under investigation.Except for the non-significant seasonal variation in the carbon nitrogen ratio of coarse roots of Larix principis-rupprechtii and the organic carbon content of Larix olgensis,there was significant seasonal variation in other indicators.The organic carbon content,total nitrogen content,carbon phosphorus ratio and nitrogen phosphorus ratio of coarse roots in summer and autumn were significantly higher than those in spring,while the total phosphorus content and carbon nitrogen ratio were significantly lower in spring,however,there was no significant difference in these indicators in summer and autumn.The interspecific comparison of the four species showed that the carbon,nitrogen and phosphorus contents of Larix kaempferi had a larger coefficient of variation and a wider range than the other three species,indicating that seasonal changes had the greatest impact on the growth of Larix kaempferi;The higher nitrogen phosphorus ratio indicates that nitrogen restriction has the smallest impact on the growth of Larix kaempferi.For forest cultivation,it is recommended that nitrogen fertilizer is applied to promote the growth of stand during growth season,especially to Larix olgensis and Larix principis-rupprechtii.