Just What The Doctor Ordered

This year we tried out variable rate prescriptions for applying fertilizer.  At the beginning of the year we grid sampled some of our irrigated acres in order to try to solve some problems we have been having.  Grid sampling is the process of collecting soil samples in an organized fashion.  A GPS system is used to create a grid and will guide the user to the appropriate location to take a sample.  The sample is then tagged with the longitude and latitude of the sample soil and sent to a test lab.

The lab then runs tests on the soil fertility for each sample.  All the samples are then complied and used to create a fertility map.  A fertilizer prescription is created in order to address the fertility deficiencies throughout the field.  After the prescription is created it is then loaded into our guidance system.  The guidance system then communicates with the strip tiller, via a rate controller, the amount of fertilizer it is dispensing at every point in the field.  Below is a picture of the variable rate map that we created.  Each color change in the map represents a change in the amount of fertilizer being applied.  Once I started creating the map I decided I wanted to do a test strip in the middle of the field.  I wanted to test how much of an increase in yield I would see with an increase in the fertilizer rate.  Now that we have yield mapping on our combines I can view the results as soon as we pick the corn in the field.

We are just in the beginning phases of using variable rate fertilizer but in the future I would like to vary the rate of seed population, fertilizer, and the rate of irrigation throughout our farm.  Using variable rate applications will allow our farm to be more efficient in its use of input costs. 

-Field Pharmacist Ryan