Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2002
Publication Date: 1/1/2003
Citation: Brown, M.F., Whitford, W.G. The effects of termites and straw mulch on soil nitrogen in a creosotebush (Larrea tridentata) dominated Chihuahuan Desert ecosystem. Journal of Arid Environments. 2003. v. 53(1). p. 15-20.
Interpretive Summary: This study was designed to examine the hypothesis that low levels of soil nitrogen in creosotebush-dominated ecosystems were related to the low levels of organic matter in the soils. Because subterranean termites had been shown to reduce soil organic matter, straw mulch was added to plots with termites present and plots from which termites had been removed by insecticide application. Soil nitrogen was significantly higher on plots without termites but addition of straw mulch did not affect soil nitrogen levels on these plots. Soil nitrogen was affected by termites but the addition of carbon in the form of straw mulch did not affect soil nitrogen.
Technical Abstract: The effects of organic matter (wheat straw) and subterranean termites on concentrations of soil nitrogen were measured on insecticide-treated plots to eliminate termites and by adding straw mulch to insecticide-treated and insecticide-untreated plots. Soil nitrogen was significantly higher, 435 mg g (-1 power) soil at 0-5 cm depth, on plots with no termites than on plots with termites (340 mg g (-1 power) soil). There were no differences in total soil nitrogen at soil depths of 5-10 cm. Soil nitrogen was higher in soils with termites than in soils with termites excluded on straw-amended plots. On the plots without straw amendments, total soil nitrogen was higher in soils without termites than in soils with termites present. Termites had no significant effect on total soil nitrogen under shrub canopies in comparison with intercanopy soils. The addition of straw mulch did not result in higher soil nitrogen content in soils without termites. Termites were more important as effectors of soil nitrogen than addition of organic matter in the form of wheat straw.