米老排人工林营养元素积累及其分配格局

Accumulation and distribution of nutrients in Mytilaria laosensis plantation

对广西宁明县34年生米老排人工林的5种营养元素(N、P、K、Ca、Mg)的含量、积累量及其分配特征进行了调查和分析。结果表明:米老排不同器官营养元素含量的变化趋势为树叶>干皮>树枝>树根>干材,树叶和干材各营养元素含量为N>K>Ca>P或Mg,树枝和树根中则是K或Ca>N>Mg>P,干皮为Ca>K>N>P>Mg;米老排人工林营养元素总储存量为1671.74kg/hm2,其中乔木层营养元素储存量(1497.01kg/hm2)占89.55%,灌草层(23.00kg/hm2)和凋落物层(151.73kg/hm2)营养元素储存量分别占1.37%和9.48%;米老排人工林乔木层营养元素年净积累量为44.03kg/(hm2·a),不同养分元素年净积累量的顺序为N>K>Ca>Mg>P,每积累1t干物质需要5种营养元素5.10kg。

Mytilaria laosensis distributed in south subtropical zones in China, with fast growth and high-quality timber, great ecological and economic value. The contents ,accumulation and distribution of the nutrient elements （N ,P,K, Ca and Mg） in M. laosensis plantation（34-year-old）were studied in Ningming County of Guangxi, China. The results showed that the contents of these five nutrient elements in different organs of M. laosensis plantation were in the order of leaves 〉 stem bark 〉 branch 〉 root 〉 stem wood. The order of the nutrient elements contents was N 〉 K 〉 Ca 〉 P or Mg in leaves and stem, and K or Ca 〉 N 〉 Mg 〉 P in branch and root, and Ca 〉 K 〉 N 〉 P 〉 Mg in stem bark. The total nutrient storage in M. laosensis plantation was 1 671.74 kg/hm2. Of the total storage of nutrients, 89.55% was distributed in arbor layer, 1.37% at forest floor layer, 9.4g % at standing litter layer. The annual net accumulation of nutrient dements of M. laosen- sis plantation was 44.03 kg/（ hm2 -a）, and the order of nutrient storage of five kinds of nutrient elements was： N 〉 K 〉 Ca 〉 Mg 〉 P. 5.10 kg mineral nutrients of five elements were needed for the accumulation of a ton of dry organic matter.