SAGEBRUSH DYING IN SMALL PASTURE - Ask Extension
The sagebrush has completely died in a 1-1/2 acre pasture. Sagebrush thrived until 2yrs. ago when the irrigation canal less than 100 ft from the west ...
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SAGEBRUSH DYING IN SMALL PASTURE #868215
Asked May 13, 2024, 2:22 PM EDT
The sagebrush has completely died in a 1-1/2 acre pasture. Sagebrush thrived until 2yrs. ago when the irrigation canal less than 100 ft from the west end of the pasture was piped. Also, large juniper trees were cut down on the west boarder which served as a windbreak. We have had a horse in pasture for over 30 yrs. being fed adequate hay with no effect on the sagebrush previously. Every other year we spray for mustard weed in the front area where there is no sagebrush which has not affected the sagebrush in past years either. The adjacent neighbor's sagebrush hasn't been affected. He has an abundance of juniper trees and no livestack. I am curious why my sagebrush and other plants in the back half of the pasture died.
Deschutes County Oregon
Expert Response
Hi Nick,
Could you send me some photos of the pasture including the area where the juniper were cut and the canal was piped? Also, when was the last application of herbicide on the mustard and what product/herbicide was used?
Thanks
Gordon
Could you send me some photos of the pasture including the area where the juniper were cut and the canal was piped? Also, when was the last application of herbicide on the mustard and what product/herbicide was used?
Thanks
Gordon
The first photo shows the contrast between my property and the neighbors. The second photo shows where the canal was piped about 25 ft from my west fence line. The third photo shows the west fence line where several large junipers were taken out for the canal piping. Please see attached the application description using Opensight & Broncmax on June 3, 2022. Those are the same products we have used since 2016 with no effect on the sagebrush.
Thank you
Nick Crannell
Thank you for the details and photos, Nick.
The difference between your and your neighbor's sagebrush is quite distinct, and that makes me think that the piping of the canal and removal of the juniper were not the main cause.
Opensight contains two active ingredients: aminopyralid and metsulfuron methyl. The former is a commonly used woody plant/brush control herbicide with a relatively long half-life in the soils. I'd hypothesize that enough herbicide built up in the soil over successive applications that it was finally enough to kill the sagebrush plants.
Gordon
The difference between your and your neighbor's sagebrush is quite distinct, and that makes me think that the piping of the canal and removal of the juniper were not the main cause.
Opensight contains two active ingredients: aminopyralid and metsulfuron methyl. The former is a commonly used woody plant/brush control herbicide with a relatively long half-life in the soils. I'd hypothesize that enough herbicide built up in the soil over successive applications that it was finally enough to kill the sagebrush plants.
Gordon
The pasture's front half, bare ground plus weeds, was the only area sprayed. The back half with the sagebrush was not sprayed. Would the herbicide have spread somehow to the back half with successive applications?
Nick
Ah. Okay. One path of movement of this herbicide would be through manure. Aminopyralid is pretty inert in grass plants and when passing through livestock. There's a warning on the label to ensure that manure, compost, and bedding from forage treated with Opensight not be applied to broadleaved plants. I suspect that the horse(s) moved some herbicide from the treated areas into the untreated area over the course of the past several years.
Thanks for your efforts and assessment. I appreciate it!
Nick
