Biomass Partitioning and Root Architecture Responses of Loblolly Pine Seedlings to Tillage in Piedmont and Coastal Plain Soils

Abstract

Abstract In the southeastern United States, site preparation methods often involve surface and subsurface tillage used singly or in combination. However, growth responses to these treatments are often inconsistent across sites and physiographic regions. In an effort to gain insight into how pine growth is affected by tillage, the effects of two treatments, machine planting and combination tillage (i.e., disking, subsoiling, and bedding), were examined in terms of biomass partitioning and root system architecture of loblolly pine seedlings (Pinus taeda L.) on Piedmont and Upper Coastal Plain sites in Alabama and Georgia. Our objectives were to evaluate the effects of combination tillage on root system development and examine whether potential effects were related to aboveground measures. Seedling allometry indicated that for all sites and both physiographic regions, machine planting and combination tillage treatments resulted in similar biomass partitioning above- and belowground. Furthermore, on both Piedmont and Coastal Plain sites, root architecture was primarily influenced by the presence of the subsoil “rip” regardless of treatment. These conclusions suggest that compared to machine planting, combination tillage did not affect biomass partitioning on the functional rooting zone of these young pines to a degree that was biologically significant. South. J. Appl. For. 28(2):76–82.