琉球松-琉球木荷混交林生长及其土壤特性的研究

Characteristics of Growth and Soil Properties in a Mixed Stand of Pinus luchuensis and Schima wallichii kort. ssp. liukiuensis Bloenb. in Subtropical Zone

对日本亚热带琉球松 -琉球木荷混交林的生长特性及其对土壤理化性质的影响进行了较为系统的研究。结果表明 :与纯松林相比 ,混交林生长优势显著 ;林分胸高断面积提高 6 3 3%～ 113 3% ;蓄积量提高 1～ 2倍。树高胸径关系分析结果表明混交林中松树个体的高生长得到显著促进 ,其树高生长量比纯林提高 4 6 0 %。混交林地表凋落物层蓄积量平均为 9 81Mg·hm- 2 ,仅为纯松林的 5 6 0 % ,其分解常数 (k)平均为 0 2 0 ,而纯林则高达0 4 6。凋落物层养分贮量除Zn略高于纯林 (11 1% )外 ,混交林均显著低于纯松林 ,约为纯林的 5 7 1% (N)～ 86 2 %(Mn)。混交林土壤理化性质得到明显改善 ,土壤总孔隙度提高 ,保水性能及土壤水分状况比纯松林优越 ;土壤有机质、全氮及有效磷含量均明显高于纯林土壤。

Characteristics of tree growth and soil properties in the mixed and pure Pinus luchuensis stands were investigated in northern Okinawa, southwest Japan. The results showed that the production of the pine_broadleaf mixed stands were much higher than that of the pure pine stand. The total basal area and stocking volume for the mixed stands were, respectively, 55 2～72 1 m 2 ·hm -2 and 406～638 m 3 ·hm -2 ; which were 63 3 %～113 3 % and 94 2 %～205 3 % greater than those of the pure pine stand, respectively. Result from the analysis of height- DBH relation of individual tree indicated that the growth of tree height for luchu pine in the mixed stands was significantly promoted. The mean height of pine trees in the mixed stands reached 18 4 m which was 46 0 % higher than the pure stand. Litter accumulation on the ground surface in the mixed stands averaged 9 8 Mg·hm -2 , and its decomposition constant was 0 20 However, for the pure pine stand, they were 17 5 Mg·hm -2 and 0 46, respectively. Amounts of nutrient accumulation in A 0 horizon under the mixed stands were evidently lower than that under the pure pine stand except for Zn. Soils under the mixed stands had higher porosity, greater water_holding capacity, and better water regime in comparison with the pure pine stand. The contents of soil organic C, total N and available P were much greater in the mixed stands than in the pure pine stand. It is evident that the mixture of P. luchuensis and Schima wallichii kort. ssp. \%liukiuensis\% Bloenb could increase the turnover rate of forest floor organic matter and accelerate nutrient cycling. The results from this study demonstrate that the mixture is suitable for maintaining soil fertility and site productivity in long_term, promoting its growth and establishing a stable, man_made forest ecosystem.