Controls on the Storage and Loss of Soil Organic Carbon with Reforestation of Abandoned Pastures

在全球范围内，土壤碳储量一般随粘粒含量的增加而增加，通过土壤呼吸的碳损失可以从年平均温度和降雨量中相对较好地预测。 在生态系统尺度上，负责碳的保留和损失的机制还不太清楚。 本研究将使用一个长期的和复制良好的牧场到森林的时间序列，以研究的因素，有助于土壤碳储存和损失。 这项研究将跟踪C从植物凋落物输入到分解到土壤储存，以及通过CO2损失。 植物组织的化学性质在次生演替过程中发生变化，因此凋落物化学对生态系统过程的影响也可能随着时间的推移而变化。 该研究将使用现场和实验室实验和稳定的放射性同位素，比较和对比凋落物化学，地上和地下凋落物输入的作用，和土壤化学性质在地下C循环超过82年的再造林。 本研究将有助于理解植物如何影响土壤碳动态，提高预测造林和再造林对碳固存影响的能力。

At a global scale, soil carbon storage generally increases with clay content, and carbon loss via soil respiration can be relatively well predicted from mean annual temperature and rainfall. At an ecosystem scale, the mechanisms responsible for C retention and loss are less well understood. This study will use a long-term and well-replicated pasture-to-forest chronosequence to study the factors that contribute to soil C storage and loss. The research will follow C from plant litter inputs through decomposition to storage in soils, and loss via CO2. Chemical properties of plant tissues change during secondary succession, and thus the impact of the litter chemistry on ecosystem processes is also likely to change over time. The research will use field and laboratory experiments and stable- and radioisotopes to compare and contrast the roles of litter chemistry, above- and belowground litter inputs, and soil chemical properties in belowground C cycling over 82 yr of reforestation. This research will contribute to understanding of how plants influence soil C dynamics, and improve the ability to predict the effects of reforestation and afforestation on C sequestration.