The effects of termites and straw mulch on soil nitrogen in a creosotebush (Larrea tridentata) dominated Chihuahuan Desert Ecosystem

摘要

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 mgg~(-1) soil at 0-5 cm depth on plots with no termites than on plots with termites (340 mgg~(-1) 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.