闽西北不同类型毛竹林养分分布及生物循环特征

Nutrient distribution and biological cycle characteristics in different types of Phyllostachys pubescens forest in Northwest Fujian

以福建省永安市集约经营的毛竹纯林(Ⅰ)、竹阔混交林(Ⅱ)和竹针混交林(Ⅲ)3种类型林分为研究对象,对其N、P、K、Ca、Mg元素分布格局及生物循环特征进行了研究。结果表明,毛竹林N、P、K、Ca、Mg5种养分元素的排列顺序为土壤层>乔木层>凋落物层>灌木层>草本层,其中土壤层(0～60cm)养分累积量占系统养分总量>99%。3种林分养分元素累积量的排列顺序为Ⅱ>Ⅰ>Ⅲ,分别为146196.59、144466.35和105002.59kg.hm-2,其中植被层养分累积量的排列顺序为Ⅰ>Ⅱ>Ⅲ,凋落物层和土壤层养分累积量排列顺序为Ⅱ>Ⅰ>Ⅲ,竹阔混交林土壤层和凋落物层养分累积量最高,立地生产潜力最大。林分Ⅰ和Ⅱ的养分利用系数显著高于林分Ⅲ,反映了林分维持高生产力需要消耗更多的养分元素;循环系数排列顺序为Ⅲ>Ⅱ>Ⅰ,竹针混交林和竹阔混交林维持林木生长所需的养分元素少于毛竹纯林;毛竹纯林养分周转时间最长,竹阔混交林次之,竹针混交林最短,分别为31.89年、12.39年和12.23年,混交林周转时间显著低于毛竹纯林。竹阔混交林既有较高的生产力,又有较强的养分归还能力,是一种较好的经营方式。

Taking the intensively managed pure bamboo（Phyllostachys pubescens）stand（Ⅰ）,bamboo stand mixed with broadleaved trees（Ⅱ）,and bamboo stand mixed with coniferous trees（Ⅲ）in Yong＇an County of Fujian Province as test objects,this paper studied the distribution patterns of N,P,K,Ca,and Mg and the characteristics of biological cycle in the stands.The nutrient accumulation in the stands was in the order of Ⅱ Ⅰ Ⅲ,being 146196.59,144466.35,and 105002.59 kg·hm-2,respectively,and that in different layers of the stands was in the order of soil layer tree layer litter layer shrub layer herb layer,with the proportion in soil layer（0-60 cm）accounted for more than 99% of the total.The nutrient accumulation in vegetation layers was in the order of Ⅰ Ⅱ Ⅲ,and that in soil layer and litter layer was in the order of Ⅱ Ⅰ Ⅲ.Stand Ⅱ had the highest nutrient accumulation in its soil layer and litter layer,and thus,the greatest productive potentiality.The nutrient utilization coefficient of standsⅠ and Ⅱ were significantly higher than that of stand Ⅲ.The higher productivity depended on more nutrients.The nutrient cycling coefficient was in the order of Ⅲ Ⅱ Ⅰ.Stands Ⅲ and Ⅱ needed lesser nutrients than stand Ⅰ.The nutrient turnover time was in the order of Ⅰ Ⅱ Ⅲ,being 31.89,12.39,and 12.23 years,respectively,and there was a significant difference between stands Ⅰ,Ⅱ and Ⅲ.The bamboo stand mixed with broadleaved trees had higher productivity and stronger nutrient return ability,being a better management pattern of P.pubescens.