Is your phone ringing off the hook with growers complaining about yellow wheat fields? If so, you are not alone!
I have looked at many wheat fields in the past 10 days and pulled many diagnostic plant and soil samples. Problem areas are generally confined to side slopes on sandy fields or around the perimeter of fields where fertilizer could not overlap.
Test results from problem fields suggest a sulfur problem even where sulfur was applied. Soil test results show adequate sulfur in the soil but plant results show low to deficient sulfur. How can this happen?
Remember all of the rain we had this winter? Sulfur is a mobile element and can leach below the root zone with excessive rainfall. Sulfur will leach to the clay layer in our heavy textured soils and will accumulate for plant uptake once plant roots reach clay layer. When sulfur leaches in sandy soil it is gone and must be replenished for a balanced nutritional program. Our wheat crop has a shallow root system this year because of abundant rainfall. Why should roots grow deep when there is adequate moisture near the soil surface?
Now that the cool night temperatures are gone, wheat is growing 24 hours a day and growing quickly. When this happens there is a demand for vegetative growth but if root system is limited the plant cannot pick up all the nutrients it needs.
Nitrogen is more than sufficient in yellow fields however sulfur is not. Consequently there is a high n/s ratio in the plant. Given time wheat will return to a green color. However when the crop is under stress a yield loss will occur if the sulfur problem is not corrected. Time is NOT on our side, and sulfur should be applied to correct the problem.
Generally 100 lbs. of k mag broadcast will fix the problem. The extra potassium will benefit the next crop more than the wheat crop. With k mag in short supply other substitutions can be made but it will take at least 20 lbs. of sulfur per acre to turn the crop around.
Listed are pictures of sulfur problems with wheat and examples of compacted and non compacted areas in sandy soils and root development in these areas. Below are some links to view a Wheat Report, & Plant Tissue Analysis.
REMINDER: UPCOMING WHEAT FIELD DAYS! Excellent Opportunity to learn more about wheat production as well as Harvey’s Wheat Varieties in the OVT trials!!
If you have questions do not hesitate to give me a call.
Sincerely,
Rick Morris
