连续施肥对毛竹林生长特征及生物量空间构型的影响

以福建省永安市天宝岩国家级自然保护区不同施肥时间的毛竹Phyllostachys pubescens林为研究对象,对不施肥(林分Ⅰ)、施肥5a(林分Ⅱ)、施肥13a(林分Ⅲ)毛竹林的生长特征和生物量分配格局进行了研究.结果表明:施肥显著提高毛竹林分的生物量,3种林分生物量的排列顺序为林分Ⅱ＞林分Ⅲ＞林分Ⅰ,分别为101347 8,91376 0和60.697 0 t·hm-2.长时间施肥林分竹秆生物量与总生物量的比例有下降趋势,而枝、叶、根、蔸所占比例有上升的趋势.竹材主要的经济组分为竹秆,竹秆所占生物量比例下降,可能降低施肥的经济增益.灌木层生物量的排列顺序为林分Ⅲ＞林分Ⅰ＞林分Ⅱ,分别为1 643.37,1 543.70和389.35 kg·hm-2,其中灌木枝和叶生物量与灌木层生物量比例的排列顺序为林分Ⅲ＞林分Ⅰ＞林分Ⅱ,根生物量所占比例的排列顺序为林分Ⅱ＞林分Ⅰ＞林分Ⅲ,长期施肥可以增加枝、叶生物量比例,降低根的生物量比例.草本层叶生物量比例随着施肥时间的延长而降低,草根生物量所占比例呈升高趋势.林分林分Ⅰ,林分Ⅱ和林分Ⅲ的凋落物现存量分别为3.79,4.07和6.64 t·hm-2,施肥可以增加林分凋落物量,可能和施肥提高了毛竹林生产力有关.

Growth characteristics and biomass distribution of Phyllostachys pubescens stands with changes in fertilization time

It was important to study the Phyllostachys pubescens stands with different fertilization periods（Ⅰ：without fertilization,Ⅱ：5 years of fertilization,and Ⅲ：13 years of fertilization）growth characteristics and biomass distribution pattern for maintain the long-term productivity.Growth characteristics and biomass distribution of three Phyllostachys pubescens stands with different fertilization periods were studied by field survey in Yong＇an County,Fujian Province.Results showed that biomass was in the order of ⅡⅢⅠ.The mass fraction of bamboo stems decreased with fertilization time,whereas the mass fraction for bamboo branches,leaves,roots,and culm stumps increased.Biomass of the shrub layer was in the orderⅢⅠⅡ.The mass fraction for shrub branches and leaves increased in forestⅢ,was in the order of ⅢⅠⅡ,and the mass fraction for shrub roots decreased in forestⅢ,was in the order of ⅡⅠⅢ.The mass fraction of grass leaves decreased with fertilization time as the mass fraction of grass roots increased.The litter mass increased with fertilization time.Therefore,litter increases could be related to higher productivity with fertilization in bamboo stands;also,since major economic issues with bamboo concerned its culm,the decrease in bamboo culms with fertilization increases over time could reduce economic gains which fertilization sought to increase.