Hidden Hunger – What's Happening Below Ground

As the growing season winds down, it is a great time to assess what practices have proven profitable and which ones need refinement for the future. One method that many growers are adopting is tissue testing to discover whether or not their fertility programs resulted in ‘hidden hunger’ issues that were not necessarily manifested via visual deficiency symptoms. The tissue tests are utilized in conjunction with soil tests to see if ample soil fertility has actually reached the plant.

In some cases, growers are surprised to find that although their soils tests showed adequate levels of fertility their plants indeed were deficient. What could be the cause? For the most part nutrients must move to the plant via the process of diffusion or mass flow which requires two things:

#1- the nutrients to get into solution

#2- a gradient pathway for and to the roots.

Issues can occur below ground that increase soil density and cause roots to grow in a restricted manner. Sometimes the cause is conditions at planting, but vertical tillage equipment in the fall or spring could also be a source.

In some cases growers utilize vertical tillage in an attempt to mix residue while leveling the soil surface but this could be creating hidden berms or mounds of soil below ground that contain a density change on the surface of the hump. This can sometimes cause roots to grow over the top or around the mounds limiting a plant’s ability to reach fertility that otherwise shows up on a soil test but becomes unavailable to the plant due to these root restrictions.

As you begin to consider tillage options for this fall, it is a good time to audit your tillage practices to determine if they could be creating hidden hunger in your plant due to unseen issues below ground. New equipment has been introduced that allows growers to mix residue, leave a level soil surface and at the same time reduce or eliminate those below ground berms that may restrict root growth and lead to hidden hunger in the field the next year.