Increased rainfall variability and reduced rainfall amount decreases soil CO2flux in a grassland ecosystem

作者：C. W. Harper, John M. Blair, Philip A. Fay, Alan K. Knapp, Jonathan D. Carlisle · 发表于：Global Change Biology · 年份：2005 · DOI：10.1111/j.1365-2486.2005.00899.x · 被引用次数：407 · 研究领域：Soil Carbon and Nitrogen Dynamics、Plant Water Relations and Carbon Dynamics、Pasture and Agricultural Systems

Abstract Predicted climate changes in the US Central Plains include altered precipitation regimes with increased occurrence of growing season droughts and higher frequencies of extreme rainfall events. Changes in the amounts and timing of rainfall events will likely affect ecosystem processes, including those that control C cycling and storage. Soil carbon dioxide (CO2) flux is an important component of C cycling in terrestrial ecosystems, and is strongly influenced by climate. While many studies have assessed the influence of soil water content on soil CO2flux, few have included experimental manipulation of rainfall amounts in intact ecosystems, and we know of no studies that have explicitly addressed the influence of the timing of rainfall events. In order to determine the responses of soil CO2flux to altered rainfall timing and amounts, we manipulated rainfall inputs to plots of native tallgrass prairie (Konza Prairie, Kansas, USA) over four growing seasons (1998–2001). Specifically, we altered the amounts and/or timing of growing season rainfall in a factorial combination that included two levels of rainfall amount (100% or 70% of naturally occurring rainfall quantity) and two temporal patterns of rain events (ambient timing or a 50% increase in length of dry intervals between events). The size of individual rain events in the altered timing treatment was adjusted so that the quantity of total growing season rainfall in the ambient and altered timing treatments was the sa...