干扰／利用方式对喀斯特石灰土团聚体分布及其碳氮含量的影响  

Carbon and nitrogen contents in calcareous soil aggregates affected by disturbance and land use in karst region,China

作　　者：肖霜霜[1,2,3] 叶莹莹[1,2,3] 张伟[1,2] 吴敏[1,2,3] 王克林[1,2] 

机构地区：[1]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,广西环江547100 [3]中国科学院大学,北京100049

出　　处：《生态学杂志》2016年第5期1140-1146,共7页Chinese Journal of Ecology

基　　金：中国科学院科技服务网络计划(STS计划)“广西喀斯特区生态服务提升与民生改善研究示范”(KFJ-EW-STS-092);国家自然科学基金项目(41471445,31270555)资助

摘　　要：基于长期控制实验，研究了干扰／利用方式（封育、砍伐、火烧，种植牧草和种植玉米等5种处理方式）对典型喀斯特地区石灰土团聚体分布及团聚体碳、氮含量的影响，结果发现：各干扰／利用方式土壤团聚体组成都以〉5和2～5mm粒级为主，其中封育和砍伐地〉5mm粒级团聚体含量显著高于其他3种方式，火烧和玉米地则在〈2mm的4种小粒级团聚体含量呈现较高值；全土和团聚体中有机碳和总氮含量基本以封育最高，砍伐、火烧居中，而以牧草和玉米地最低；各干扰／利用方式下团聚体有机碳分布规律不同，随团聚体粒级减小，封育和砍伐地呈波浪形分布，玉米地呈倒“V”形分布，团聚体总氮分布较平稳，团聚体碳、氮在0．054～0．25mm均呈现最低值；封育和砍伐处理的〉5mm团聚体碳、氮占全土含量和贡献率显著高于其他3种处理，且各干扰／利用方式土壤团聚体碳、氮主要存在于〉5mm和2—5mm粒级（均为60％～82％），可将〉2mm粒级团聚体作为喀斯特山区土壤碳、氮固持的特征团聚体。Carbon and nitrogen contents in aggregates are influenced greatly by human distur- bance and land use. However, it is uncertain how disturbance and land use affect carbon and ni- trogen in aggregates, especially for calcareous soil in karst region in southwest China, where is extremely vulnerable to human disturbance. Based on a long-term field trial in Huanjiang Obser- vation and Research Station, this study identified the distribution characteristics of carbon and ni- trogen in calcareous soil aggregates under five kinds of disturbance and land use treatments （en- closure, cutting, burning, pasture, and maize cropland）. The results showed that the aggregate composition was dominated by particles 〉5 mm and 2-5 mm under the different disturbance and land uses. The aggregates of enclosure and cutting lands showed significantly higher values in par- ticles 〉5 mm than those of the other three land-use patterns, while burning land and maize crop- land had high values in 〈2 mm fraction. In whole soil and all size classes of aggregate particles, enclosure had the highest values of organic carbon and total nitrogen, followed by burning and cutting, while the values of organic carbon and total nitrogen in pasture and maize cropland were relatively lower. The distribution patterns of carbon in different aggregates were variable： enclo- sure and cutting presented an undulation distribution, and maize cropland showed an inverted ＂V＂ shape. The lowest values of organic carbon and total nitrogen appeared in particles 0.054- 0.25 mm. The contribution of organic carbon and total nitrogen in 〉5 mm fraction under enclo- sure and cutting was significantly higher than that under the other three land-use patterns. Most of the organic carbon and total nitrogen were accumulated in 〉5 mm and 2-5 mm fractions, which both accounted for 60%-82%. The results suggest that particles of aggregate size 〉2 mm hold the major parts of the soil carbon and nitrogen in karst calcareous soils. Our findings could provide fundamen

关 键 词：喀斯特 石灰土 干扰 利用方式 团聚体 有机碳氮 

分 类 号：S152.4[农业科学—土壤学]