Grid sampling reveals how the nutrients are distributed across a field. By collecting more soil samples on a field we gain a better understanding of the nutrients available. By understanding the nutrients available, we can be confident the fertilizer dollars are being used efficiently.
In each of these cases the soil sample allows for the fertilizer prescription to be optimized and the chance of a return on the investment improved.
Grid soil sampling and variable rate application of lime, gypsum and fertilizers adds a level of control and security to a fertilizer program.
Over-application of lime can have a negative affect on the crop by increasing the soil pH beyond a neutral level. This causes some nutrients like phosphorus to become less available for the crop. Grids provide a way to prevent the over-application of lime and at the same time save on input costs.
In some areas, regulations are in place that limit the application of fertilizer once a maximum threshold has been met. Grid soil sampling provides a means to monitor soil nutrient levels and ensure fertilizer and manure application meet those standards.
Grid sampling is a convenient way to answer questions before scaling up the entire farm. By combining grids with yield analysis one can explore what nutrients are limiting yield and correct the issue. It is also possible to set up on-farm learning plots to explore how variables interact, like population and fertility.
Our team of Crop Consultants and Precision Ag Specialists provide the services needed to create variable rate prescriptions for nearly any controller. The controller files are delivered by a local agronomist or transferred via the cloud directly to the applicator. We provide a turnkey solution to make it simple to get variable rate prescriptions into the equipment, whoever the applicator.
Grid Soil Test Points
Soil Test Results
Results Map – pH
Directed soil sample points are shown in red. Grid sample points are in blue. The purple background shows the phosphate distribution.
On average, a grid soil sample will last four years, but that is not a black and white rule. A better answer to this question is, it depends.
The preferred approach is to select a few points from the original grid sample and monitor the nutrient levels at those points. Each season directed soil samples are pulled and compared to the previous samples. This shows how the low and high nutrient levels are responding to the variable rate applications. Which allows for adjustments to the fertilizer prescriptions to be made when needed.
As the seasons pass the original grid will gradually no longer represent how the fields nutrients are distributed. By monitoring with the directed points a crop consultant can determine when a field has changed enough to justify re-gridding.
The industry standard grid sample size is two and a half acres per sample. This size likely became the standard due to the economics of sampling at smaller versus larger sizes. The smaller the grid, the more samples and time required to collect them which increase the cost of the service.
There is research to support the idea that when grid size becomes much over four acres per sample the points become too far apart to be statistically sound.
We offer a choice of sample sizes in order to fit the needs of the client but the majority of our grids are pulled every two and a half acres.