We firmly believe there is no single ‘best’ soil sampling method for every field. Depending upon your goals and each field’s history, we help you determine the most effective soil sampling approach to use (management zones or grid sampling).
It is important to consider field history and conditions of each field when establishing management zones. Soil type maps, yield maps, aerial photos, topography, soil electrical conductivity, previous cropping, fertilizer, manure application history, and many other factors can be used to help create the right management zones.
It can be more beneficial for farmers and consultants to learn about the conditions of specified management zones in each field instead of sampling arbitrary squares (grids) every four years. Management zones improve return on fertilizer dollars; allowing for more targeted use of resources in certain areas.
Grid sampling is sometimes preferred because it can better describe nutrient variability across a field due to more samples per given area. Grids are easy to create with modern field software and do not require an agronomist to set sample points.
There are certain drawbacks and limitations of grid sampling, though, that should be considered:
- Higher cost than zone sampling due to the additional samples required.
- Sample size must match the sophistication of the application equipment being used, as not all applicators can handle small grids.
- Grids may straddle soil types.
On large fields, grid sampling is a way to establish future management zones, making it easier to get a base line on a particular field. If you’re pushing to maximize yield, there is value in the precision that comes from intensive grid sampling and other site-specific information.
In order to initially determine baseline nutrient status, the ‘best’ approach for your fields may be to do a one-time intensive grid sampling and then develop and utilize management zones thereafter.