Soil CO2 Efflux and Root Productivity in a Switchgrass and Loblolly Pine Intercropping System

Forests

John R. Seiler¹  Brian D. Strahm¹  Zakiya H. Leggett²  Paliza Shrestha³  Eric B. Sucre⁴ 

[1] Department of Forest Resources and Environmental Conservation, Virginia Tech, 313 Cheatham Hall, Blacksburg, VA 24061, USA;Department of Forestry and Environmental Resources, North Carolina State University, 3122 Jordan Hall, Raleigh, NC 27607, USA;Department of Plant and Soil Science, University of Vermont, 230 Jeffords Hall, Burlington, VT 05405, USA;Production Forestry Research Manager and Senior Scientist, Weyerhaeuser Company, Northern Timberlands Strategy and Technology, Springfield, OR 97478, USA;

关键词: Panicum virgatum L.;    Pinus taeda L.;    soil respiration;    intercropping;    autotrophic respiration;    heterotrophic respiration;   

DOI  :  10.3390/f7100221

来源: DOAJ

【 摘 要 】

Switchgrass intercropped with loblolly pine plantations can provide valuable feedstock for bioenergy production while providing ancillary benefits like controlling competing vegetation and enhancing soil C. Better understanding of the impact of intercropping on pine and switchgrass productivity is required for evaluating the long-term sustainability of this agroforestry system, along with the impacts on soil C dynamics (soil CO2 efflux; RS). RS is the result of root respiration (RA) and heterotrophic respiration (RH), which are used to estimate net C ecosystem exchange. We measured RS in intercropped and monoculture stands of loblolly pine (Pinus taeda L.) and switchgrass (Panicum virgatum L.). The root exclusion core technique was used to estimate RA and RH. The results showed pure switchgrass had significantly higher RS rates (July, August and September), root biomass and length relative to intercropped switchgrass, while there were no significant changes in RS and roots between intercropped and monoculture loblolly pine stands. A significant decrease in switchgrass root productivity in the intercropped stands versus monoculture stands could account for differences in the observed RS. The proportions of RS attributed to RA in the intercropped stand were 31% and 22% in the summer and fall respectively, indicating that the majority of the RS was heterotrophic-driven. Ancillary benefits provided by planting switchgrass between unutilized pine rows can be considered unless the goal is to increase switchgrass production.

【 授权许可】

Unknown