不同氮水平下秸秆和酚类、有机酸对土壤碳含量的影响

利用采集自FACE(Free Air Carbon Dioxide Enrichment)技术平台上田间培养的土壤样品,通过温室培养的方法,研究不同CO₂浓度下导致作物生物量增加和更多酚类、有机酸输入对土壤碳含量的影响. 结果表明,CO₂浓度升高时,通过根系分泌的酚类、有机酸对土壤各粒级分配的影响受秸秆加入和氮水平的调控. 在有无秸秆加入条件下,酚类、有机酸的加入主要增加了粒径>250和<53 μm土壤的碳含量. 单位土壤各粒级的碳含量均增加,粒径>53 μm增加幅度较大;在没有秸秆加入的常规氮水平与有秸秆加入的低氮水平下,碳含量变化幅度较大. 表明来自高CO₂浓度条件下秸秆和酚类、有机酸对土壤碳的固定具有重要的作用和意义. 

Effects of Straw, Phenol and Organic Acids on Soil Carbon in Different Sized Particles under Different Nitrogen Levels

This study examined the change of soil carbon affected by the increaseof biomass crops and more phenol and organic acid input in soil due to elevatedCO₂ concentration. A culture experiment using soil from a field after being cultured one year under FACE platform with two CO₂ levels (ambient CO₂ and elevatedCO₂) and two N levels (normal N and low N) was conducted in a greenhouse at thesame N treatment with the field. The results indicated that compared to soil from ambient CO₂, turnover of different soil particles in soil from elevated CO₂ was increased and affected by added straw and nitrogen levels. Soil carbon content in particles of size >250 and <53 μm was increased due to input of phenoland organic acid under straw added or not condition. Soil carbon content in each particle per unit of soil was increased and the increase magnitude was larger in particles >53 μm. The change was larger at normal N with no straw and at lowN with straw added. The results indicated that straw, phenol and organic acid played a more important role and had great significance in soil carbon sequestration under elevated CO₂ conditions. However, the effect of decomposition of strawon carbon in different particle sizes was dependent on different N levels, which was known poorly and should be investigated further.