涪江中游4种造林树种碳氮磷化学计量及养分重吸收特征

C∶N∶P Stoichiometry and Nutrient Resorption Characteristics among Four Afforestation Tree Species in the Middle Reaches of Fujiang River

【目的】探究涪江中游不同造林树种间植物-凋落叶-土壤连续体的生态化学计量以及叶片养分重吸收特征,为该区域人工林的经营管理提供理论支持。【方法】以涪江中游4种常见造林树种(柏木Cupressus funebris、马尾松Pinus massoniana、桉树Eucalyptus robusta、构树Broussonetia papyrifera)为研究对象,探讨不同树种植物叶片、凋落叶和土壤碳(C)、氮(N)、磷(P)生态化学计量及叶片氮磷养分特征。【结果】①构树叶片和凋落叶的N含量均显著高于其他树种;桉树和构树的叶片及凋落叶P含量显著高于柏木和马尾松,且马尾松土壤P含量最低;②桉树和构树叶片的养分重吸收效率总体上高于马尾松和柏木;③叶片和凋落叶N、P含量分别与土壤N、P含量呈显著正相关,N重吸收效率与叶片N和P含量、凋落叶P含量呈显著正相关,P重吸收效率与叶片N、凋落叶N∶P、土壤C∶P和N∶P呈显著正相关。【结论】在涪江中游地区,这4种造林树种的叶片-凋落叶-土壤之间存在显著的相关关系,构树和桉树叶片N、P含量相对较高,养分重吸收能力较强,对养分限制具有较高的适应能力。因此,在研究区域内改造马尾松、柏木等低效人工林时可以适量补植构树和桉树,有助于提升该区域人工林质量。

【Objective】This study is aimed to explore the ecological stoichiometry and nutrient reabsorption characteristics of the leaves-foliar litter-soil continuum among different afforestation species in the middle reaches of Fujiang River,and to provide theoretical support for the management of plantations in this region.【Method】This study measured the C,N,P contents in leaves,foliar litter and soil,and analyzed the ecological stoichiometry and nutrient reabsorption in Cupressus funebris,Pinus massoniana,Eucalyptus robusta,and Broussonetia papyrifera,which are among the main afforestation species in the middle reaches of the Fujiang River.【Result】①The N contents of leaves and foliar litters in B.papyr⁃ifera were significantly higher than that of other species,and the P contents of leaves and foliar litters in E.robusta and B.papyrifera were significantly higher than that of C.funebris and P.massoniana.The soil P content in P.massoniana plantation was lower than the other species.②The nutrient reabsorption efficiency of E.robusta and B.papyrifera was higher than that of C.funebris and P.massoniana.③Soil N and P contents were positively correlated with the N and P contents in leaves and foliar litters.The N reabsorption efficiency(NRE)was positively correlated with N and P contents in leaves as well as P contents in foliar litters.The P reabsorption efficiency(PRE)was positively correlated with N content in leaves,foliar litter N∶P,soil C∶P and N∶P.【Conclusion】The results above indicated that there were significant correlations among leaves,foliar litters and soil in the middle reaches of Fujiang River.The N,P contents of leaves in E.robusta and B.papyrifera were relatively higher compared with those of C.funebris and P.massoniana,with stronger nutrient resorption ability,which illustrates a higher adaptability when subjected to soil nutrient limitations.Therefore,E.robusta and B.papyrifera could be properly supplemented in the management of the low-efficiency C.funebris and P.massoniana plantations,which would contribute to the improvement of planation quality in this area.