Soil EC Mapping on Your Farm
Gary Suess, Precision Ag Specialist
firstname.lastname@example.org (507) 273-7043
If you’re a grower in our trade territory, you all have something in common: your fields vary. The variability may be in water holding capacity, organic matter, yield potential, nematode pressure, soil pH, or many other possibilities. One thing is certain – managing these fields as if they were uniform is not the best strategy.
Before you can manage soil variability, or manage inputs differently, you need to map it with accuracy and intensity that truly captures the variations. Soil EC testing is an effective way to do this map these soil variations. Soil EC is soil electrical conductivity – a measurement of how much electric current the soil can conduct. While soil EC has no direct effect on crop growth or yield, the benefits of EC mapping comes from the relationships that frequently exist between EC and a variety of other soil properties that are highly related to crop productivity. These properties include water-holding capacity, topsoil depth, soil drainage, organic matter levels, and subsoil characteristics. EC readings correlate strongly to soil grain size, making it an effective way to map soil type and texture because smaller soil particles such as clays have a high conductivity, silts have a medium conductivity, and sands have a low conductivity.
A popular way to measure soil EC is done by pulling a Veris Technologies sensor in passes about 50-60 ft apart across the field. The Veris sensors use spring loaded coulter electrodes mounted on a steel frame sensor cart. The sensor measures the soil EC on the go as the cart is pulled across the field. Because the soil types on the farm do not change, the zones identified by a Veris soil EC map are consistent over time, making it a one-time investment.
Once soil EC mapping of a farm is done, Progressive Ag Center agronomists can then work with growers to devise management zones for the farm, create variable rate seeding prescriptions, and better manage nitrogen applications. Options for variable rate application of seed, fertilizer, and water can be explored when producer and agronomists knowledge is combined with EC soil mapping. By optimizing the placement of inputs, the potential for a return on investment improves. The opposite can also be said. By not placing inputs in areas with poor soil, dollars can be saved or shifted to other locations. This also leads to a higher potential for a return.
If you would like to read more about Variable Rate Management Zones here is a link to an article that was published in the February 2016 issue of the Corn and Soybean Digest. http://cornandsoybeandigest.com/precision-ag/better-variable-rate-management-zones
If you would like to know more about this new technology I encourage you to contact a member the All American Co-op Progressive Ag Center agronomy sales team.