Smoke effects on plant growth due to reduced light

Asked September 5, 2017, 2:39 PM EDT

I'm noting a reduction in the growth of our grass in the pasture. It has slowed down noticeably over the past month. This slowdown is more than normal due to increased temperatures of August. I was wondering if the smoke is having a filtering effect on the light that reaches the ground, particularly early to mid morning and then again towards evening. It appears the visible light is being reduced, in example I'm able to look at the sun and see it's shape clearly. Have you received any other similar observations?

Crook County Oregon

1 Response

The smoke is decreasing the amount of light which has also reduced the temperature each day by a couple of degrees compared to what it would have been without smoke. This run of hot weather and smoke since the end of June is almost unprecedented. In my 28 years here, I cannot think of a worse summer! Alfalfa and other legumes love this weather as long as you are irrigating properly, Our cool season grass species on the other hand do not like this hot weather. The cumulative effect of the heat over two months has certainly upped the evapo-transpiration of the plants, so more irrigation water was needed to keep plants growing. If a person is grazing tight to the ground, this would also increase surface soil temperature and increase evaporation as well as hold the soil biological life in check as well (near surface).

Call me if you want to talk some more or have more questions at 541-447-6228 and also to sign up for our C.O. Ag Newsletter .if you are not receiving it.

Mylen Bohle
Area Extension Agronomist
Central Oregon
OSU Extension Service