中国温带阔叶红松林不同演替系列土壤有机碳矿化特征

土壤有机碳矿化与陆地生态系统碳循环和全球气候变化关系密切,为准确评估中国温带小兴安岭阔叶红松林不同演替系列土壤有机碳矿化特征及变化规律。以年代序列法代替群落次生演替过程,采用室内恒温培养(碱液吸收法)测定阔叶红松林不同演替系列(中生演替系列、湿生演替系列、旱生演替系列)6种群落类型土壤有机碳矿化量和矿化速率。3个演替系列土壤有机碳含量均表现出一致的剖面变化特征,随着土层深度的加深有机碳矿化量逐渐降少。且不同演替系列土层间有机碳矿化量不同,中生演替系列原始阔叶红松林土壤有机碳累计矿化量最大,其次为旱生演替系列,湿生演替系列最小。3个演替系列土壤有机碳矿化速率随时间变化呈现基本一致的趋势,即培养前期快速下降、后期逐渐趋于平稳。3个演替系列6种群落类型土壤有机碳矿化差异显著,表现为原始阔叶红松林白桦次生林云冷杉红松林红松枫桦次生林蒙古栎红松林蒙古栎、黑桦次生林。阔叶红松林不同演替系列土壤有机矿化采用非线性指数拟合效果较好。阔叶红松林不同演替系列土壤有机碳矿化与土壤全氮、凋落物量显著正相关,与土壤含水率、容重、土壤酸碱度显著负相关。不同演替系列群落的演替历史、土壤质地和养分状况等生态因子是导致阔叶红松林不同演替系列土壤有机碳矿化差异的原因。

Characteristic mineralization of soil organic carbon in different successional series of broadleaved Korean pine forests in the temperate zone in China

The soil carbon cycle and global climate change are closely related to the mineralization of carbon in terrestrial ecosystems. To accurately assess the characteristics of carbon mineralization and variation in the mineralization of carbon in different succession series (mesosere series, hydrosere series, and xerosere series) in the broadleaved Korean pine forests of the Xiaoxing''an Mountains in the temperate zone of China, we measured the mineralization of carbon and the mineralization rate based on the chronosequence method. The results showed that the carbon mineralization rate and the extent of carbon mineralization in the three successional series exhibited consistent cross-sectional variation, and gradually decreased with depth. The extent of carbon mineralization in the different successional series was different. The virgin forest accumulated soil organic carbon and mineralization in the mesosere was the greatest among the three series, followed the xerosere and hydrosere series. The carbon mineralization rate of the three successional series varied with time and exhibited a consistent trend (decreasing quickly during the first stage and gradually stabilizing). The six kinds of community-type carbon mineralization in the three successional series were significantly different. The carbon mineralization rate of the three successional series in broadleaved Korean pine forests was original forest > Betula platyphylla-Pinus koraiensis forest > Picea koraiensis-Pinus koraiensis forest > Betula costata-Pinus koraiensis forest > Quercus-mongolica-Pinus koraiensis forest > Betula davurica-Pinus koraiensis forest. Mesosere series carbon mineralization fit a nonlinear exponential better. Carbon mineralization of soil organic carbon was significantly positively correlated with soil total nitrogen and litter-fall amount in different successional series in the broadleafed Korean pine forests, and negatively correlated with soil moisture, soil bulk density, and soil pH. In short, successional histories, soil texture, and nutrient status resulted in differences in soil organic carbon mineralization of the different succession series in the broadleaved Korean pine forests.