I did some informal evaluations of the various fertilizer treatments on the Blank Slate on Thursday with Lonny Smith. Thanks for visiting, Lonny!
One thing that we noticed was leaf disease as pictured above. The interesting part of the story to me was how the incidence of leaf disease varied greatly throughout the field.
On the strips where 10 gallons of fertilizer was applied at planting (5 gal Sure-K plus 5 gal Pro-Germinator with micros) we saw the most disease. To be fair, my soils had almost zero fertility and very little organic matter. We needed to apply more than 10 gallons of fertility to raise a decent crop. Where we followed up by side-dressing another 10 gallons of the same mix we saw much less disease.
On strips where 15 or 20 gallons of the same fertility mix were used at planting as the total fertility treatment, there was disease present. It was less than the 10 gallon strip, but more than the areas where 10 gallons was applied at planting and another 10 gallons at side-dress.
The lesson learned from the Blank Slate field is this. If fertility runs short, the plant is weakened. A weak plant is more susceptible to disease. Once a plant has one stress (in this case it’s nutrient deficiency), adding more stress (i.e. disease) will multiply the misfortune. A slightly nutrient deficient and slightly diseased plant will now be the first to suffer from moisture stress, heat stress, etc.
We’ll see how this all turns out when the combine runs through the field in the fall. By the way, I snapped a picture of the first tassel on the Blank Slate while we were walking the field on Thursday.
There is some unevenness in the field due to the lack of topsoil in areas, poor drainage, etc. We’re still a little bit away from seeing the whole field tasseling. If the disease really starts to blow up across the field, it will be difficult to time a fungicide application to hit when the entire field is fully tasseled.