摘要
为阐明黄土高原典型区域土壤轻组有机碳(LFOC)和重组有机碳(HFOC)含量随土壤类型、土层和土地利用方式的变化规律,分析了从北向南依次分布的干润砂质新成土(神木)、黄土正常新成土(延安)和土垫旱耕人为土(杨凌)等典型土壤剖面(0～200 cm)LFOC和HFOC含量及分布特征。结果表明,从南到北,土壤LFOC和HFOC含量均显著下降(P<0.05),整体来看,黄土高原典型区域土壤LFOC含量占有机碳比例偏低;LFOC含量及在土壤有机碳中的分配比例随土层加深而递减,其比例变化范围为1%～26%;土地利用方式对浅层土壤LFOC和HFOC含量影响较为显著,草地土壤0～60 cm土层LFOC和HFOC含量均高于同层次农田土壤(P<0.05),60 cm土层以下差异不显著;土壤LFOC和HFOC含量与微生物量碳、微生物量氮含量均呈极显著正相关关系(P<0.01),前者的相关性系数更高,分别为0.841和0.507,表明土壤LFOC与微生物关系非常密切,是土壤微生物重要的碳和能量来源,极易受土地利用方式和微生物活性影响,同时表明用LFOC的变化更能快速有效地说明土壤碳库的变化规律。
In order to evaluate the effects of location,soil depth,and land use on the soil light fraction organic carbon（LFOC） and soil heavy fraction organic carbon（HFOC）,we investigated the contents and the distribution characteristics of soil LFOC and HFOC of three types（Ust-Sandiic-Entisols at Shenmu,Los-Orthic-Entisol at Yan＇an and Eum-Orthic-Anthrosol at Yangling） soils profiles（0-200 cm） sampled along a north-south gradient on the Loess Plateau.The results indicated that the contents of soil LFOC and HFOC decreased significantly（P0.05） from south to north.The ratios of LFOC in soil organic carbon ranged from 1% to 26%.LFOC content and the ratios of LFOC in soil organic carbon significantly（P0.05） decreased with soil depth.Both of them were lower than the previous reports in other regions of China.Land use closely（P0.05） correlated with the contents of LFOC and HFOC fractions in the upper soil layers.Compared with farmland,the contents of soil LFOC and HFOC in grassland were significantly higher at the 0-60 cm layers,but had no significant difference below 60 cm soil layers.Both soil LFOC and HFOC contents positively correlated with soil microbial biomass nitrogen and carbon contents,the former with a correlation coefficient of 0.841 and 0.507,respectively.This suggested that soil LFOC was one of the most important carbon and energy sources for soil microbial growth and thus more liable to the impacts of microbial activities and land use change.Our results also implied that soil LFOC could more effectively reflect the variation of soil organic carbon pools than HFOC.
出处
《自然资源学报》
CSSCI
CSCD
北大核心
2011年第11期1890-1899,共10页
Journal of Natural Resources
基金
西北农林科技大学创新团队项目
中央高校09基本科研业务费专项资金(z10921007)
08校内博士科研启动费(z1110020833)
中国科学院"西部之光"地方项目(2008DF02)
