摘要
针叶林混交阔叶树是改善土壤肥力、增强林地养分循环的重要措施,而混交效应受到针叶树种自身特性的影响,马尾松(Pinus massoniana)和湿地松(P.elliottii)是亚热带地区广泛种植的针叶树种,但目前2种针叶林对阔叶树混交的响应特征还不清楚。选取马尾松、湿地松纯林以及木荷(Schima superba)补植后形成的马尾松—木荷和湿地松—木荷混交林为研究对象,采集剖面土壤样品,测定土壤容重、有机碳(OC)、全氮(TN)和全磷(TP)含量,计算碳氮磷储量及化学计量特征,比较不同森林类型间的异同。混交阔叶树显著增加了马尾松林0—60cm各土层OC含量,而湿地松纯林与其混交林间OC含量无显著差异。同时,混交增加了2种针叶林土壤TN含量。马尾松林混交后0—60cm土层碳储量显著增加95.8%,而混交阔叶树对湿地松林土壤碳储量无显著影响。混交阔叶树后马尾松和湿地松林0—60cm土壤总氮储量分别增加了15.8%和28.4%,但混交对土壤磷储量无显著影响。混交显著增加了马尾松林0—40cm各土层C/N,而降低了湿地松林0—10cm土层C/N。混交阔叶树后马尾松林0—20cm土层C/P和0—10cm土层N/P显著增加,而混交仅增加湿地林0—10cm土层N/P。混交阔叶树增加了针叶林土壤氮储量,但对磷储量无显著影响,同时混交改变了土壤碳氮磷生态化学计量特征。与湿地松林相比,马尾松林土壤养分含量、储量及其化学计量特征对混交的响应更敏感。
Mixing broad-leaved tree species is an important measure to improve soil fertility and enhance nutrient cycling in coniferous forests,but their mixed effects vary with coniferous tree species.Masson pine(Pinus massoniana)and slash pine(P.elliottii)are widely planted in the subtropical China.However,the mixed effects of the two coniferous forests are still not clear.Soils with 60 cm depth were collected in four forest types:masson pine plantation(MP),slash pine plantation(SP)and two mixed forest of Schima superba with MP(MPM)and SP(SPM),to determine the bulk density,organic carbon(OC),total nitrogen(TN)and total phosphorus(TP)concentrations.The carbon,nitrogen and phosphorus storages and their stoichiometry were also calculated.The OC concentration of MP in 0-60 cm soil layer significantly increased by mixing with broad-leaved tree species,but there was no significant difference in OC concentrations be-tween SP and SPM.Meanwhile,the TN concentrations of MP and SP increased in response to mixed effects.The OC storage of 0-60 cm soil depth in MPM increased by 95.8%compared with MP,while mixing with broad-leaved species had no effect on soil OC storage in SP.The total N storage of 0-60 cm soil depth in MP and SP significantly increased by 15.8%and 28.4%respectively after mixing with broad-leaved tree species.The soil C/N of MP in 0-40 cm soil layer increased and soil C/N of SP in 0-10 cm soil layer decreased after mixing with broad-leaved tree species.The soil C/P in 0-20 cm and soil N/P in 0-10 cm of MP while significantly increased induced by mixed effect,whereas there was only significant difference in soil N/P in 0-10 cm layer between SP and SPM.Soil nitrogen storages increased after the two coniferous forests mixed with broad-leaved tree species,while no significant influence of mixed effects was observed on the phosphorus storage.Moreover,the characteristics of soil carbon,nitrogen and phosphorus stoichiometry were influenced by mixing effects.And,the soil nutrients concentrations,storages and their stoichiometry characteristics of MP were more sensitive to mixed effects compared with those of SP.
引文
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