摘要
对马尾松 (Pinusmassoniana)人工林内N、P、K、Ca、Mg 5种养分元素的含量、积累、分配和生物循环以及它们随林分年龄的变化趋势进行了研究。结果表明 :针叶的养分含量最高 ,树干材的养分含量最低 ,凋落物的养分含量与树枝或树皮的养分含量接近 ,土壤中K、Mg元素丰富 ,N、P、Ca 3种元素亏缺。树叶、树枝、树皮和树根中各元素含量大小顺序为K >N >Ca>Mg >P ,树干材中则是Ca>K >N >Mg >P ,5种元素含量随马尾松林分年龄的增加呈逐渐减少的趋势。 5种元素贮存总量为 46 0 .19～ 195 0 .32kg·hm-2 ,随生长过程中生物量的增加而增大。树干的养分分配比随林分年龄增加呈抛物线状 ,在不同时期森林采伐利用木材所带走养分的损失量大不相同 ,应选择合理的采伐时间尽量减少森林采伐对林分的养分循环和林地的生产力造成不良影响。年积累量为 49.35～ 5 7.5 3kg·hm-2·a-1,随林分年龄增加呈减少的趋势。吸收量为 137.6 3～ 388.19kg·hm-2 ·a-1,归还量为 84.99～ 338.84kg·hm-2 ·a-1。不同年龄阶段马尾松林的养分利用系数为 0 .0 7～ 0 .34 ,循环系数为 0 .6 0～ 0 .83,周转期为 3.35～ 2 2 .6。马尾松随年龄增加 ,早期自身养分利用率低 ,但其归还速率快 ,周转期短 ,有利于林地生产力维持 ,林分到达成熟期养分的?
The concentrations, accumulation, distribution and biological cycling of 5 nutrient elements (N, P, K, Ca, Mg) in Pinus massoniana stands of different age classes were studied. The results show that nutrient concentrations were the highest in needles and the lowest in stems. Nutrient concentrations among branch, bark and litter were similar. The soil had abundant K and Mg, but was short of N, P and Ca. The order of nutrient elements concentration was K>N>Ca>Mg>P in needle, branch, bark and root, and Ca>K>N> Mg>P in stem. Nutrient concentration increased with stand growth. The total nutrient storage in Pinus massoniana stands ranged from 460.19 kg·hm -2 to 1950.32 kg·hm -2. The nutrient distribution in stems varied in the form of a parabolic curve with increasing stand age. It is important to select a rational cutting time in order to reduce the negative impact of harvesting on forestland fertility. The nutrient retention accounted for 49.35-57.53 kg·hm -2·a -1, which decreased with stand growth. The nutrient absorption and return ranged from 137.63 kg·hm -2·a -1 to 388.19 kg·hm -2·a -1, and 84.99 kg·hm -2·a -1 to 338.84 kg·hm -2·a -1, respectively. The nutrient utilization coefficient, cycling coefficient and recycling period were estimated to be 0.07-0.34, 0.60-0.83 and 3.35-22.6. In early stage stands, nutrient use efficiency in Pinus massoniana stands was lower but recycling rate was higher and turnover period was shorter. Mature stands had a lower nutrient recycling rate and a longer turnover period, so the trees extract more nutrient elements from soil. Hence measures should be taken to facilitate the successional process to reach a stable zonal community.
出处
《植物生态学报》
CAS
CSCD
北大核心
2002年第1期89-95,共7页
Chinese Journal of Plant Ecology
基金
国家林业局重点项目( 96_34)
关键词
年龄阶段
马尾松
人工林
养分循环
Pinus massoniana plantation, Age class, Nutrient elements, Distribution, Biological cycling
