Abstract
We measured soil respiration, fine root biomass production, and microbial biomass along a fertilization gradient (0, 56, 112, and 224 kg N ha
-1 per year) in 7-year-old cottonwood and loblolly pine plantations, established on a well-drained, Redbay sandy loam (a fine-loamy, siliceous, thermic Rhodic Paleudlt), in northwest Florida. Annual soil respiration rate was significantly greater in cottonwood (781 g C m
-2 per year) than in loblolly pine (692 g C m
-2 per year). Nitrogen (N) fertilization had a significant negative effect on soil respiration in cottonwood, but no effect was observed in loblolly pine stands. Annual fine root production was significantly greater in cottonwood (221 g m
-2 per year) than that in loblolly pine (144 g m
-2 per year) without N fertilization effect. Microbial biomass, however, was reduced by N fertilization in both species. These results suggest that belowground responses to fertilization can vary widely between conifers and hardwoods.
Parent Publication
Citation
Lee, Kye-Han; Jose, Shibu. 2004. Belowground Processes in Nitrogen Fertilized Cottonwood and Loblolly Pine Plantations. Gen. Tech. Rep. SRS–71. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pp. 446-449