Biochar influence on subterranean termites: 36 month evaluation

Abstract

This first interim research report concerning subterranean termite activity summarizes the 36-month evaluation of a 5-year study-in-progress on the Stanislaus National Forest, Calaveras County, California, within the Sierra Nevada Mountains. The Lakemont timber salvage site was clear-cut during 2017 and received biochar treatments during November 2017. Wood stakes, ground-boards and PVC termite monitoring stations were installed during 2018. Evaluation and sampling began during 2019. Study plots were established across the open field salvage site. Non-disturbed forest tree plots were also established on the open field periphery. Open field and tree plots were randomly assigned one of two biochar amendments to the soil surface or designated as a non-treated control. Wood stakes were placed in plots to monitor decay and changes in wood soundness each year as well as evaluate subterranean termite activity. To gain additional insight into subterranean termite activity, all open field and tree plots also contain in-ground termite monitoring stations and soil-surface ground-boards. Currently, forest tree plots have not exhibited sufficient termite activity to draw conclusions concerning effects of biochar on foraging termites. However, biochar applications to open field soil may have increased termite activity in the high rate open field plots. The highest biochar application rate of 22,417 kg•ha-1 (10 tons•acre-1) exhibited the greatest termite foraging activity after 36 months compared with the 6,725 kg•ha-1 (3 tons•acre-1) and non-treated control plots. However, another two years or longer evaluations should more clearly identify definitive trends and allow more accurate conclusions concerning effects of biochar soil amendments on subterranean termite foraging activity.

Citation

Kard, Brad M.; Page-Dumroese, Deborah S.; Jurgensen, Martin F.; Tirocke, Joanne M.; Cook, Stephen P.; MacKenzie, Martin; Shelton, Kevin T. 2022. Biochar influence on subterranean termites: 36 month evaluation. In: Arango, Rachel A.; Pureswan, Deepa S., eds. 2022. Proceedings of the 7th North American Forest Insect Work Conference; Shaping Forests: Action in a Changing World. FHAAST-2022-01. Washington, DC: U.S. Department of Agriculture, Forest Service, Forest Health Assessment and Applied Sciences Team. p. 160-166.