College News

Ag Instructor Vic Martin: Understanding Crop Plant Differences

Great Bend Tribune
Published June 17, 2023

The drought monitor report as of Tuesday, June 13 indicates drought in our area has retreated to extreme drought.  Overall, in the western half of the state and extreme Southeast Kansas, conditions are still improving to moderate drought, abnormally dry and even no moisture problems in extreme Northwest Kansas.  The six to ten-day outlook (June 20 to 24) indicates leaning to a 40 to 50% chance of leaning to above normal temperatures and a 33 to 40% chance of leaning to above normal precipitation.  The eight to fourteen-day outlook (June 22 to 28) indicates a continued 33 to 40% chance of leaning to above normal temperatures and the same for precipitation.  It’s obvious in our area how much the precipitation has benefitted our summer crops, especially corn and the soybeans in the ground.  Also, alfalfa and perennial pastures have really improved.  And the forecast, while for above normal temperatures, isn’t for extreme heat.  Combined with higher humidity, this allows crops to better cope with the heat.  We are still in a drought but the pattern, if this continues, should allow for decent to good fall crops.

Producers do what they do for a reason.  Maybe you have wondered why corn here is planted from approximately mid-April to mid-May and as you get plant later yields are reduced.  Yet soybeans have a much wider planting window for the same variety but can’t be planted as early as corn or even milo for example.  Here’s why.

  • The only crop that really is native to Kansas is the sunflower and that is after going to Russia several hundred years ago, being developed into the sunflower we grow today and coming back.  Wheat from the Middle East, corn from Mesoamerica, soybeans and alfalfa from Asia, and grain sorghum from Sub-Saharan Africa for example.
  • For grasses such as corn, wheat, and milo, the growing point stays below the soil surface for an extended period of time.  For winter wheat here usually around mid-March.  This protects the growing point form cold air temperatures that could damage or kill it.  For corn, the growing point doesn’t reach the soil surface until about V6, around twelve inches.  Sorghum is similar.  So, if something like a frost or insect feeding damages the above ground part of the plant at an early stage, the growing point is safe.  For broadleaves like soybeans and alfalfa, when the seedling emerges, that is the growing point so a frost of feeding removes that portion of the plant, the plant will die.  Later, on, if the growing point is lost, secondary growing points can take over and while height won’t increase, the plant will bush out.  This is also why cut or grazed grass regrow quickly while with alfalfa, you remove all the growing points and dormant ones then grow.
  • For flowering, our wheat needs to accumulate a certain amount of cold before is can flower along with increasing daylength.  Our soybeans here are long night plants and will flower once night length increases to a predetermined amount which is dependent on the maturity level.  Finally corn and milo growth stages are reached based on a certain amount of heat accumulation.  The amount depends on the maturity level of the plant.