林分年龄与坡位对燕山北部山地典型植物群落土壤有机碳含量的影响

Effects of Stand Age and Slope Position on Soil Organic Carbon Content in Typical Plant Communities in Mountain Areas of Northern Yanshan

摘要: 基于36个土壤剖面的实测数据，研究了林分年龄与坡位对燕山北部地区4种典型群落类型土壤有机碳含量的影响。结果表明：次生杨桦林0~10 cm层，9a生有机碳含量(76.85 g/kg) > 28a生(67.26 g/kg) > 16a生(65.61 g/kg)。在20~40 cm和60~70 cm土层范围内，有机碳含量表现出随着林分年龄的增加而降低的趋势。人工落叶松林在0~10 cm层次上，最大值出现在18a生中(86.25 g/kg)，其次为9a生(79.16 g/kg)和33a生(68.33 g/kg)，再次为43a生(63.46 g/kg)，最低为5a生(48.25 g/kg)，在20~70 cm范围内，有机碳含量随年龄增长而增加的趋势不明显。在深层土壤(20~70 cm)中，成熟林(43年生)各层次有机碳含量要明显高于其他各发育阶段相应层次的有机碳含量。各群落土壤有机碳在从下坡–中坡–上坡环境梯度上没有表现出一致的规律性。在绣线菊灌丛群落中，不同坡位之间有机碳含量的变化规律最为复杂。榛子灌丛群落表现出有机碳含量随着坡位的降低而呈现出增加的趋势。次生杨桦林和人工落叶松林的0~10 cm中，上坡有机碳含量，中坡次之，下坡最低，而其余各层次的变化规律不一致。

Abstract: Based on the measured data of 36 soil profiles, the effects of stand age and slope position on soil organic carbon content of 4 typical community types in northern Yanshan were studied. The results showed that the secondary poplar birch forest was from 0 to 10 cm layers with 9a organic carbon content (76.85 g/kg), >28a (67.26 g/kg) and >16a (65.61 g/kg). In the 20 - 40 cm and 60 - 70 cm soil layers, the organic carbon content decreased with the increase of stand age. Larch plantation in 0 - 10 cm level, the maximum value appeared in 18a students (86.25 g/kg), followed by 9a (79.16 g/kg) and 33a (68.33 g/kg), once again for the 43a (63.46 g/kg), the lowest is 5a (48.25 g/kg). In the 20 - 70 cm range, the organic carbon content’s increasing trend along with the increase of age is not obvious. In deep soil (20 - 70 cm), the organic carbon content of mature forest (43 year old) is obviously higher than that of other stages of development. The soil organic carbon in different communities did not show consistent regularity from the slope to the middle slope to the uphill environment gradient. In the shrub community of Spiraea, the change law of organic carbon content in different slope positions is the most complex. The content of organic carbon in hazel shrub community showed an increasing trend with the decrease of slope position. In the 0 - 10 cm of the secondary Yang Hualin and the artificial larch forest, the organic carbon content in the slope is lower than the middle slope and the lowest in the slope, while the change law of the other levels is inconsistent.