晋西黄土区不同森林树种及其林地土壤养分含量的变化

The Nutrient Content Variations of Different Forest Species and the Forest Soil in Loess Region of Western Shanxi

[目的]探究晋西黄土区不同树种营养器官(叶、枝、干、根)及其土壤的养分含量变化特征。[方法]通过野外样地调查和取样分析方法,对3种典型森林树种(刺槐、侧柏、辽东栎)不同器官及其林地土壤有机碳、全氮、全磷含量进行了研究,并探讨了不同树种叶片与其土壤C、N、P化学计量的关系。[结果]辽东栎、刺槐和侧柏的叶片有机碳含量分别为468.43、454.96、438.53 g·kg-1,刺槐、辽东栎和侧柏叶片的全氮含量分别为27.52、20.74、12.73 g·kg-1,辽东栎、侧柏和刺槐叶片的全磷含量分别为2.73、2.15、1.35 g·kg-1,叶片C∶N值为侧柏>辽东栎>刺槐,C∶P、N∶P值分别为刺槐>侧柏>辽东栎、刺槐>辽东栎>侧柏;3个树种树枝的有机碳含量均最大,树叶的全氮含量均最大,而树干的全氮含量均最小。侧柏、辽东栎、刺槐树枝的全磷含量分别为3.07、3.07、1.87 g·kg-1,显著比其它器官的大;3种森林土壤的C、N、P含量均随土层的加深而降低,且0 10 cm土层的含量最大,C∶N、C∶P、N∶P值随土层深度的变化不一致;刺槐叶片的有机碳、全磷含量与土壤C∶N值显著或极显著负相关;侧柏叶片的有机碳含量均与土壤C∶N、C∶P、N∶P值极显著负相关,叶片N∶P值与土壤C∶N、C∶P、N∶P值均极显著正相关;辽东栎叶片的有机碳含量、C∶P值与土壤有机碳含量极显著负相关。[结论]辽东栎、刺槐和侧柏的有机碳含量均较高,分别为468.43、454.96、438.53 g·kg-1;辽东栎和刺槐对晋西黄土区干旱环境的防御能力比侧柏强,当地环境较适宜辽东栎的生长发育,而刺槐和侧柏的生长分别受土壤P和N的限制。

[Objective]To explore the nutrient content variation characteristics of vegetative organs （leaf,branch, stem and root）of different tree species and the forest soil in loess region of western Shanxi Province.[Method] The methods of investigation and samples analysis were used to study the contents of soil organic carbon （SOC）,to-tal nitrogen （TN）and total phosphorus （TP）in different organs of three typical forest species （Robinia pseudoaca-cia,Platycladus orientalis,Quercus liaotungensis）and in the forest soil.The stoichiometric relationships of C,N and P between leaf and the soil were discussed.[Result]The results showed that the leaf SOC contents of Q.liao-tungensis,R.pseudoacacia and P.orientalis were 468.43,454.96 and 438.53 g·kg -1 ,the leaf TN contents of＆amp;nbsp;R.pseudoacacia,Q.liaotungensis and P.orientalis were 27.52,20.74 and 12.73 g·kg -1 ,the leaf TP contents of Q.liaotungensis,P.orientalis and R.pseudoacacia were 2.73,2.15 and 1.35 g·kg -1 ,the leaf C∶N value de-creased in the order of P.orientalis 〉Q.liaotungensis 〉R.pseudoacacia,the values of C∶P and N∶P decreased in the order of R.pseudoacacia,P.orientalis,Q.liaotungensis and R.pseudoacacia,Q.liaotungensis,P.orientalis respectively;The SOC content of branch of the three species were the largest.The leaf TN content was the largest, while the stem was the least of the three species.The branch TP contents of P.orientalis,Q.liaotungensis and R. pseudoacacia were 3.07,3.07 and 1.87 g·kg -1 ,which were significantly larger than that of the other organs;The contents of SOC,TN and TP in the forest soil decreased with the increase of soil depth,and the 0 10 cm soil lay-er was the largest,the values of C∶P,N∶P and C∶N in different forest soils were not consistent with the variation of soil depths;The leaf SOC and TP contents in R.pseudoacacia had an extremely significant negative correlation with the soil value of C∶N;the leaf SOC content was significantly negatively correlated with the soil values of C∶N,C∶P and N∶P,and the leaf value of N∶P in P.orientalis was significantly positively correlated with the soil values of C∶N,C∶P and N∶P;the leaf SOC content and value of C∶P in Q.liaotungensis had a significantly negative correla-tion with soil SOC content.[Conclusion]The organic carbon content of Q.liaotungensis,R.pseudoacacia and P. orientalis were higher,with 468.43,454.96,438.53 g·kg -1 respectively;Q.liaotungensis and R.pseudoacacia owned stronger drought stress tolerance than P.orientalis in arid region on the Loess Plateau of Western Shanxi;The local environment was more suitable for the growth and development of Q.liaotungensis,while it would limt the growth of R.pseudoacacia and P.orientalis due to soil P and N,respectively.