Yellow Corn Fields
Many corn growers are finding that their once dark green cornfields have now transitioned into a sea of yellow and lime green colors. It seems as though this transition has happened overnight in some areas. This situation occurs almost every year, but certain years like 2012 it becomes more noticeable. The plants most generally recover, but there are various causes and effects of this color change.
The Ugly Corn Stage
Color changes in the crop seem to suddenly appear around the V3-V5 (3-5 collars) growth stage when the crop previously looked healthy. Upon emergence, the corn plant primarily grows off of food reserves stored inside the kernel. These food reserves become less available as the crop matures and develops its nodal root system. Once the plant gets to the V3-V4 growth stage the crop starts switching from growing off of kernel reserves and becomes dependent upon its nodal root system for water and nutrient uptake. This can sometimes be a rocky transition because any injury or restriction that has occurred to the root system or poor growing conditions in general, will now start affecting the plant due to the lack of root mass and uptake. A plant with a small root system cannot support its above ground vegetative tissue and deficiencies are expressed. This timeframe is sometimes called “The Ugly Corn Stage”. The crop can fully recover, but it will first have to grow a greater root system so it can reach out and capture the water and nutrients it is lacking. Starter applications such as 2x2, pop-up, and shallow broadcast applications of UAN help this transition by positioning nutrients in closer proximity to these struggling root systems. Yellow corn fields are more apparent in the growing season of 2012 due to the adverse growing conditions that some of these corn fields received after emergence, such as scattered frost events, large fluctuations in air temperature and dry, or in a few areas, saturated soil conditions.