桂南地区4种桉树林分凋落物持水性及养分特征研究

Water Holding and Nutrient Characteristics of Four Eucalypt Stands in Southern Guangxi

以桂南地区桉树×台湾桤木混交林、桉树×红锥混交林、桉树×大叶栎混交林和桉树纯林为研究对象,对其凋落物持水性和养分特征进行研究和分析,为合理选择桉树混交林模式提供参考。结果表明:4种桉树林分凋落物现存量在4.24~6.10 t·hm^(-2),桉树混交林凋落物现存量均显著大于桉树纯林;不同类型桉树林林分凋落物最大持水率、拦蓄率、有效拦蓄变化范围分别为206.61%~310.34%、185.11%~279.84%、154.12%~233.29%,最大持水量、拦蓄量、有效拦蓄量差异显著,变化范围分别为8.76~18.85、7.85~16.97、6.54~14.15 t·hm^(-2),桉树混交林持水率和持水量均显著高于纯林。4种林分凋落物中碳含量454.150~464.950 g·kg^(-1),各林型间差异不显著;氮、磷含量分别为8.130~10.878、0.484~0.589 g·kg^(-1),表现为桉树×台湾桤木和桉树×大叶栎混交林凋落物氮、磷含量显著高于桉树纯林;3种桉树混交林凋落物中C/N、C/P均显著高于纯林。综合考虑各项指标,不同树种与桉树混交对凋落物存量、持水性和养分影响显著;台湾桤木、大叶栎与桉树混交,对促进桉树林凋落物存量、持水性和养分方面更具优势。

In order to provide reference for reasonable selection of eucalypt mixed plantation models,this paper studied water holding and nutrient characteristics of mixed plantations involving eucalypt×Alnus formosana,eucalypt×Castanopsis hystrix,eucalypt×Quercus griffithii,and pure eucalypt plantations in southern Guangxi.The results showed that the ratios of litter stock of the four types of plantations was between 4.24~6.10 t·hm^(-2) with mixed plantations having higher total litter stock than the pure eucalypt plantations.The maximum water holding rate,the maximum interception rate and effective water retaining rate of the plantations were 206.61%~310.34%,185.11%~279.84%,154.12%~233.29%respectively,the maximum water holding capacity,the maximum water retention storage and effective water retention storage of the plantations were 8.76~18.85 t·hm^(-2),7.85~16.97 t·hm^(-2) and 6.54~14.15 t·hm^(-2) respectively,with the mixed plantations having higher water holding rate and water holding capacity than the pure eucalypt plantations.The carbon content in the litter of the four stands ranged from 454.15 to 464.95 g·kg^(-1),and there were no significant differences among the different plantations for this parameter.The contents of nitrogen and phosphorus in the litter of the four plantations ranged from 8.130~10.878 and 0.484~0.589 g·kg^(-1) respectively,and the contents of nitrogen and phosphorus in the litter of eucalypt×A.formosana mixed plantations and eucalypt×Q.griffithii mixed plantations were significantly higher than those of the pure eucalypt plantation.The C/N and C/P ratios in the litter of the three mixed species plantations were significantly higher than those of the pure eucalypt plantations.In general,plantations involving different species mixed with eucalypt had significant impacts on litter stock,water holding capacity and nutrients,with the mixed plantations of eucalypt×A.formosana and eucalypt×Q.griffithii having more advantages in regard to promoting litter stock,soil water holding capacity and nutrients.