采用氧弹式热值仪测定福建惠安滨海沙地木麻黄凋落物分解过程中的热值,揭示凋落物分解过程中干物质热值、去灰分热值、灰分含量的变化规律,结果表明:凋落物起始干物质热值为21.67kJ·g-1,经过3个月平缓下降后其值为21.40kJ·g-1,到第10个月干物质热值为20.48kJ·g-1,达到最低点,与起始值相差1.19kJ·g-1,随后干物质热值开始回升,第12个月的干物质热值为20.83kJ·g-1,年平均每月降低0.07kJ·g-1;去灰分热值与干物质热值有相同的变化趋势,从开始的22.78kJ·g-1,到第9个月的最小值21.89kJ·g-1,与起始值相差0.89kJ·g-1,随后的回升速度较干物质热值快,到第12个月时达22.41kJ·g-1,但是12个月总体平均每月降低0.03kJ·g-1;凋落物灰分含量的变化与热值呈相反的变化趋势,随着时间的延长灰分含量增加,但和热值一样反映了凋落物分解的规律,开始的灰分含量为4.88%,到3个月时为4.90%,随后进入线性增长的趋势,到第12个月时达7.09%,平均每月增加0.184个百分点。不论热值还是灰分含量与气温和不同层次土壤温度都显著相关,温度,特别是气温是影响凋落物分解的重要因素。The Casuarina equisetifolia litter decomposition experiment site locates at Huian county in Fujian province, south of China. Caloric value were tested by oxygenic bomb caloric-meter. The aim was to expose the law of gross caloric value, ash free caloric value and ash content of litter during decomposition. The result showed the dynamic of the gross caloric value, ash free caloric value and ash content of Casuarina equisetifolia litter during decomposing. The decomposation lasted for three months with the caloric 21.40 kJ·g -1, to which decreased from the beginning gross caloric 21.67 kJ·g -1. At the tenth month, the gross caloric value was decreased to rock bottom, 20.48 kJ·g -1, with the range 1.19 kJ·g -1 to the begin value. After ten months of decomposation, the gross caloric value began to increase, then gross caloric value increased to 20.83 kJ·g -1 at the twelfth month, while with average decreasing ratio 0.07 kJ·g -1 per month; As to ash free caloric value, which the beginning ash free caloric 22.78 kJ·g -1, decreased to nadir, 21.89 kJ·g -1 at the ninth month, with the range 0.89 kJ·g -1 to the begin value. Then it increased faster than gross caloric did, up to 22.41 kJ·g -1 at the twelfth month. While it had average decreasing ratio 0.03 kJ·g -1 per month; The ash content, which had the contrary tendency to caloric, increased with time go by. But as the gross caloric, they all reflected the law of litter decomposition. It increased slowly from 4.88% to 4.90% in the beginning three months, then increased sharply. At the twelfth month, the ash content was up to 7.09%,and with average increasing ratio 0.184 point of percentage per month, in twelve months. While both caloric and ash content related obviously with temperature and soil temperature, especial the air temperature, so temperature was an important factor effecting the litter decomposition.国家“十五”科技攻关项目:“海岸带防护林优化配置模式和可持续经营技术研究”(2002BA516A1615
