海岸沙地木麻黄人工林凋落物归还量及其热值动态研究

Study on Dynamic of Casuarina equisetifolia Plantation Litter and Its Caloric Value on Coastal Sands

2002年11月至2003年10月在福建沿海中部惠安县崇武镇赤湖林场用收集筐法收集木麻黄凋落物,分析了凋落物各组分的归还量;应用GR-3500型氧弹式热值仪测定木麻黄凋落物的热值,并测定分析了凋落物各组分的灰分含量。结果表明:木麻黄人工林的凋落物归还量为14.18 t.hm-2.a-1,其中小枝占72.21%,枝条占23.41%,球果占2.68%,其余部分占1.69%。归还分布情况是:4—9月为归还高峰期,占总归还量的68.48%,其它月份占总归还量的31.52%。凋落物各组分灰分含量平均值顺序为:花(5.32%)>小枝(4.90%)>枝(4.69%)>球果(3.20%);凋落物干物质热值平均值顺序为:小枝>(21.11 kJ.g-1)>花(20.96 kJ.g-1)>球果(19.91 kJ.g-1)>枝条(19.89 kJ.g-1);凋落物去灰分热值的顺序为:小枝(22.19 kJ.g-1)>花(22.18 kJ.g-1)>枝条(20.87 kJ.g-1)>球果(20.63 kJ.g-1)。整个林分的能量归还量为294.55 G J.hm-2.a-1,其中小枝占主体,归还量为215.79 G J.hm-2.a-1,其次是枝条66.07 G J.hm-2.a-1,再次是果7.66 G J.hm-2.a-1,花最小5.02 G J.hm-2.a-1,各月的能流变化与凋落物生物量相似。

By burning samples in a GR-3500 Oxygen Bomb Calorimeter, the caloric value of Casurina equisetifolia litter collected by traps from Nov. 2002 to Oct. 2003 at Chihu forestry centre in Huian county in the middle of Fujian coast was analyzed, and the ash content and ash free caloric value of every components were tested. Result showed branch, cone, flower were 23.41%, 2.68%, 1.69%, respectively. The monthly dynamic variance was that the fastigium was from April to September, occupied 68.48% of total litter, and that in the other months occupied 31.52%. The average ash content order of components were flower （5. 32% ） 〉 foliage twig （4. 90% ） 〉 twig （4.69%） 〉cone （3.20%）. The average gross caloric value order of components were foliage twig （21.11 kJ·g^-1） 〉flower（20.96 kJ·g^-1） 〉cone（19.91 kJ·g^-1） 〉twig（19.89 kJ· g^-1）. The average ash free caloric value order were foliage twig （22.19 kJ·g^-1） 〉 flower （22.18 kJ·g^-1） 〉 twig （20.87 kJ·g^-1） 〉 cone （20.63 kJ·g^-1）. The C. equisetifolia plantation had high returning energy in a year, the amount of total plant was 294.55 GJ·hm^-2·a^-1. The distribution among the components are as follows： foliage twig was 215.79 GJ·hm^-2·a^-1 while twig, cone, flower were 66.07 GJ·hm^-2·a^-1, 7.66 GJ·hm^-2· a^-1 , 5.02 GJ·hm^-2·a^-1 , respectively, with same dynamic tendency as the litter biomass variance.