草业学报2016，Vol.25Issue(8)：48-55,8.DOI:10.11686/cyxb2015499
退耕草地土壤有机碳密度的空间分布及动态变化
Changes in the spatial distribution and dynamics of soil organic carbon density in grasslands converted from farmland
摘要
Abstract
The objective of this study was to explain changes in the spatial distribution and dynamics of soil or-ganic carbon (SOC)in grasslands converted from farmland in the Lanlingxi watershed,Yichang City,and thus to provide a theoretical basis for assessments of the carbon sink function of abandoned farmland.The experi-mental scenario subsets included a control group (A1 )and a split-plot design with C4 plant (Rhizoma cyperi ) litter removal (B0 )versus double litter input (B2 )in 2008.Soil samples at different depths were collected at the end of March from 2008 to 2015.SOC density was determined and the results are as follows.1)After the return of farmland to grassland,the balance of SOC density was disrupted and carbon sink functions initiated. The time taken for SOC density to reach a new dynamic equilibrium was 12 years.The annual rate of SOC se-questration was 263.5 g/m2 .2)In 2008,SOC densities in the three experimental areas ranked in the order:B2 (5504±245 g/m2 )>B0 (5476±267 g/m2 )>A1 (5392±306 g/m2 );but by 2015 the rank order had changed to A1 (6022 ±298 g/m2 )>B0 (5963 ±315 g/m2 )>B2 (5807 ±274 g/m2 ).Not only plant species but also the a-mount of litter can affect variations in organic carbon density.3)SOC densities in the control (A1 )and litter removal (B0 )areas increased continuously during the study period,while the double litter area (B2 )fluctuated in 2009-2011 and then increased continuously.Control area (A1 )conditions were more conducive to the accu-mulation of SOC.4)The changes in SOC affected by plant species and the amount of litter were mainly at the 0-20 cm soil layer,while at layers greater than 20 cm there was no change.SOC densities at different depths of farmland and grassland soils were significantly different (P <0.05).The spatial distribution of SOC density in all three experimental areas changed during the farmland-grassland succession process.The amounts of SOC accumulation varied significantly during the transition from farmland to grassland.关键词
退耕草地/土壤有机碳密度/动态变化/空间分布Key words
grassland converted from farmland/soil organic carbon density/dynamic change/spatial distribu-tion引用本文复制引用
田耀武,贺春玲,刘龙昌,王宁,徐少君,刘晶,李东升..退耕草地土壤有机碳密度的空间分布及动态变化[J].草业学报,2016,25(8):48-55,8.基金项目
国家自然科学基金项目（U1404322）资助。 （）
