Objectives:

• To evaluate the persistence and movement of picloram on rangelands in southeastern B.C.

Experimental Design:

The study has two components. For component 1, five sites were chosen throughout the Murry Gulch area. At each site 10m by 1m plots are established along the existing roadsides. These plots were sprayed with Tordon 22K® at a rate of 0.561kg/ha active ingredient. Soil samples representing depths from 0-15cm, 15-30cm, and 30-60cm are taken for picloram residue analysis. Samples are taken prior to the spray, at 24hrs following the spray and at weeks 1, 3, 6, 12, 37, 45, 52, 64, 77 and 104.

For component 2, a detailed study site has been established with three transacts to measure herbicide residues in soil, as well as three transects to measure residues in soil water. Sampling sites for both are located within the spray zone and at 2.5, 5, 10, 20, 40 and 80 m downslope of the spray zone. As with component 1, soil residues will be analyzed in the 0-15cm, 15-30cm, and 30-60cm depths. Water is extracted from the soil using tension cup lysimeters. At each sampling site, lysimeters are located at 7.5, 22.5, 45, and 90cm in the ground.

History:

• 1990 Climate station and soil moisture and soil temperature stations established.
• 1991 Preliminary soil sampling (all sites)and lysimeters established on one line
• 1992 Soil sampling (all sites) and lysimeters established on two additional lines,
• 1992 Component 1 study sites sprayed with Tordon® and soil sampling on component 1 sites.
• 1993 Soil sampling on component 1 sites.
• 1994 - 1996 Sampling continued
• 1999 Report prepared by Environment Canada.
• 2000 Additional spraying, Data collection

Status: Active

Reports and Publications:

Gluns, D.R. 1993. Picloram Residues on Rangeland: A Project Review. B.C. Min. For., Nelson, B.C. Research Summary RS-010.

Wan, M.T., D.R. Gluns, and J. Stroh. 2001. Persistence of Picloram on a rangeland in the Southern Interior of British Columbia. submitted to J. Env. Quality.