College News

Ag Instructor Vic Martin: Weed Control In Drought Conditions

Great Bend Tribune
Published May 6, 2023

The drought monitor report as of Tuesday, May 2 indicates continued expansion of exceptional drought in our area, and slight improvement in parts of Northwest and Southwest Kansas from exceptional to extreme and even small areas severe.  Yes, as bad as that sounds it is a slight improvement.  The six to ten-day outlook (May 9 to 13) indicates a 50 to 70% chance of leaning to above normal temperatures and s 33 to 40% chance of leaning to above normal precipitation.  The eight to fourteen-day outlook (May 11 to 17) indicates a 40 to 50% chance of leaning to above normal temperatures and a 33 to 40% chance of leaning to above normal precipitation.  The temperature outlook isn’t good bur at least there’s a chance of significant rainfall.  A chance as this time of year we don’t tend to receive overall soaking rains but storms so the amounts will likely vary over very short distances.

Today, since the drought won’t disappear anytime soon, it might be useful to discuss how to approach weed control under our current conditions.  You may have noticed last year that even though our crops were drastically affected by drought and heat, that weeds while exhibiting the effects of drought seemed to do much better than the crops.  Most weeds are much better adapted to our weather extremes than our traditional crops.  Most are able to produce viable seed more quickly and the perennial weeds we deal with are especially well-adapted to surviving extreme heat and drought.  Add in that most are very small seeded and easily able to germinate at or near the soil surface while our crops less so.  So, what are some ways to stay ahead pf weed pressure?

  • Start with a weed free seedbed while minimizing the loss of what soil moisture might be there.  Avoid aggressive, deep tillage.  Small weeds are easily cultivated out while larger weeds are likely best treated with herbicide.
  • Spending money on inputs is always expensive but even more of a concern over the last two years.  However, a good pre-emergence herbicide prior to or before the crop emerges is a wise investment.  The challenge for many is the need for moisture or tillage to incorporate them.  For irrigated fields, it’s not a big deal.
  • Keep small weeds small when they’re easier to control.  This is where, if practical, a shallow cultivation can be extremely effective.  Herbicides are also a good option but care must be taken in selecting the correct mode(s) of action to deal with resistance.  And on to the next point.
  • If the drought and heat continue, applying herbicides can be a challenge as under extreme conditions, the herbicide is not absorbed well into the plant and might have little control.  Also read the label and watch rates as stressed may be more vulnerable to injury by a labelled herbicide.