杉木林生态系统中土壤酚类物质含量的变化规律

以天然更新常绿阔叶林、老龄杉木 Cunninghamia lanceolata (Lamb.) Hook.]林(代表一代杉木林)、二代杉木萌芽天然更新林和二代杉木人工林作为杉木林生态系统转换模式的系列样地,研究了不同季节(3月、6月、9月和12月)4个样地0～20和20 ～ 40 cm土层土壤中酚类物质(包括总酚、复合态酚和水溶性酚)含量的变化规律.结果表明:各样地土壤总酚含量最高(278.40 ～3 012.98 μg·g-1),复合态酚含量次之(20.67～ 430.54 μg·g-1),水溶性酚含量最低(0.36～6.01 μg·g-1).各样地问不同土层中总酚、复合态酚和水溶性酚含量均值的高低变化不一致,但总体上顺着森林生态系统转换的方向(天然常绿阔叶林→一代杉木人工林→二代杉木人工林),0～20和20～ 40 cm土层中总酚和复合态酚含量以及O～20 cm土层中水溶性酚含量均值均呈现逐渐增加的趋势,而20～40 cm土层中水溶性酚含量均值则无明显变化规律.各样地0～20 cm土层中各种酚类物质含量总体上高于20～40 cm土层,表明随土层加深,总酚、复合态酚和水溶性酚含量呈现逐渐降低的趋势.各种酚类物质含量具有明显的季节变化规律,总酚和复合态酚含量总体上呈现出3月和9月较高、6月和12月较低的变化趋势,水溶性酚含量总体上呈现出随着季节变化(3月至12月)逐渐降低的趋势,不同季节间土壤中各类酚类物质含量的差异均达到了极显著水平.研究结果显示:随杉木人工林栽植代数的增加,土壤中会积累一定量酚类物质,但其中水溶性酚含量远低于使植物中毒的水平(50 μg·g-1),造成杉木中毒的可能性较小.

Change regularity of phenols content in soil of forest ecosystem of Cunninghamia lanceolata

Taking naturally renewal evergreen broad-leaved forest,old-growth forest(representing first-rotation forest) of Cunninghamia lanceolata(Lamb.) Hook.,second-rotation natural renewal sprout forest of C.lanceolata and second-rotation plantation of C.lanceolata as a series of sample plots of forest ecosystem conversion model of C.lanceolata,the change regularity of phenols content(including total phenols,complex phenols and water-soluble phenols) in 0-20 and 20-40 cm soil layers of four sample plots was studied at different seasons(March,June,September and December).The results show that total phenols content is the highest in soil of four sample plots(278.40-3 012.98 μg·g-1),complex phenols content is the second(20.67-430.54 μg·g-1),and water-soluble phenols content is the lowest(0.36-6.01 μg·g-1).The change of average contents of total phenols,complex phenols and water-soluble phenols from high to low is inconsistency among different soil layers of four sample plots.But along the forest ecosystem conversion direction(that is naturally evergreen broad-leaved forest→first-rotation plantation of C.lanceolata→second-rotation plantation of C.lanceolata),average contents of total phenols and complex phenols in 0-20 and 20-40 cm soil layers and that of water-soluble phenols in 0-20 cm soil layer appear a certain extent increasing trend,while that of water-soluble phenols in 20-40 cm soil layer has no obvious change rule.The contents of various phenols in 0-20 cm soil layer of four sample plots are generally higher than those in 20-40 cm soil layer,showing that contents of total hphenols,complex phenols and water-soluble phenols appear a gradually decreasing trend with deepening of soil layer.Each phenols content in soil shows an obviously seasonal change rule,contents of total phenols and complex phenols show a change trend of higher in March and September and lower in June and December,but content of water-soluble phenols in soil generally appears a gradually decreasing trend with seasonal variation from March to December.And content of every phenols in soil has the extremely significant difference among different seasons.It is suggested that as increasing of planting rotation of C.lanceolata plantation,phenols may be accumulated in soil with a certain amount,but the possibility of causing C.lanceolata poisoned is very low because content of water-soluble phenols in soil is obviously lower than the level(50 μg·g-1) making plant poisoned.