College News

Ag Instructor Vic Martin: Weed Control and Drought

Great Bend Tribune
Published January 22, 2023

The drought monitor report as of Tuesday, January 17 no change with about 50% of the state in extreme or exceptional drought and these systems passing through every three or so days don’t hurt but for most of the area the drought conditions are so deep it really doesn’t help.  Again, there is little hope for any change in conditions in the short or even long term.  The six to ten-day outlook (January 24 to 28) indicates a 50 to 70% chance of below normal temperatures and 33 to 40% chance of above normal precipitation, which isn’t much to begin with but it’s something. The eight to fourteen-day outlook (January 25 to February 1) indicates a continued 50 to 70% chance of below normal temperatures and a continued 33 to 40% chance of above normal precipitation.  Not much but hopefully this indicates a more active precipitation pattern that will strengthen as we move into spring.

It may seem a little odd to worry about weed control with little to almost no soil moisture.  After all, if water is lacking for crops, isn’t it also lacking for weeds?  Yes, it is, however, consider what makes a weed a weed. 

  • Weeds are better adapted to thrive in harsher conditions like a lack of soil moisture.  Most are able to germinate and grow more vigorously than our crops, especially early in the growing season.  They are well-adapted to outcompete our crops.
  • Generally, the amount of seed in potentially weedy fields far outnumber crop seed planted.  And they tend to be clustered. 
  • You plant one crop species in most fields, but you are typically dealing with multiple weed species.
  • Most weed species are excellent scavengers of water and nutrients.  They can germinate and thrive under less than ideal conditions than our crops.  And they have the advantage of typically not dealing with the pest pressures our crops do.
  • Our crops have been bred to thrive under controlled conditions to optimize production.  Weeds are genetically, quite simply, made to grow and produce more seed.

Naturally, they have other advantages.  The point here is that this drought isn’t likely going to disappear by spring planting.  There will be rains and most soils will have some moisture.  We will plant crops.  So, the dilemma here is twofold.  Keep the soil moisture we have for the crops by minimizing evaporation and insuring that soil moisture is used by our crops and not weeds. 

It’s a balancing act under these conditions in terms of inputs and operations.  One input, despite the cost that is vital is good weed control, especially at planting.  Trying to save soil moisture means minimizing or eliminating tillage so there is a likely chemical expense for a burndown.  And this is the year, moisture permitting for a soil applied herbicide to control grasses and small seeded broadleaves early in the season and not simply try to rely on post-emergence herbicides which under drought conditions are often less effective.  And naturally, a producer needs to follow the best practices for as vigorous and healthy a crop as possible.  Hopefully, conditions will change for the better in the next three months.