Monday, March 2, 2015
Both of our seed dealers have reported to us the specs on each variety of soybean seed we have purchased for 2015. Now, we can begin to build the planting prescriptions for each of those five varieties for each soybean field. Prescriptions are important, for they match planting populations to each soil type’s productivity.
These soil maps (or “soil survey” as they are commonly known) that we use as the basis for our prescriptions were developed many years ago by USDA for every county. They have many agricultural and commercial purposes, as each soil type is rated for farm productivity or how suitable they are for homesites or roads or other commercial development. The latest versions of these maps are now in digital form, which is ideal for our purposes on the farm today. Using a field boundary as a “cookie cutter”, we download into the JD Apex software the soil maps that are specific to our fields.
First step to write prescriptions: Gather seed information, which is the number of seeds in each pound. This is a different number for each variety. I have seen these numbers as low as 2300/lb and as high as 3750/lb. This year’s seed seems to be larger, therefore the numbers are in the lower part of the range. With these numbers, a chart is created giving the pounds per acre needed for low, medium, and high populations per acre. This year, these planting populations are 150K, 180K, and 195K per acre. These populations are assigned to the soil types of each field, depending on the productivity of the soil. The assigned rates are counter-intuitive, for lower rates are assigned to more productive soils, and vice versa. We’ve learned that this method of prescription use has reduced our seed costs by 10%– a significant savings, and the reason for the work to build the prescriptions.
Here are the tools needed to write planting prescriptions:
Now, let’s build a prescription:
This process must be repeated for each field for each of the 5 soybean varieties we are using in 2015.
These prescriptions are transferred to the GS 2630 screen in the planting tractor. As the tractor and planter move across the field, the system reads this prescription information and automatically adjusts the rate which the planter is applying. It is site-specific, and you can actually see the rates change on-the-go as you are planting! It’s really pretty cool to see it work.
There’s going to be some office time spent over the next few days! With the snow outside, this is a productive use of time.