Soil Sampling and Analysis

In the past, farmers estimated the conditions of an entire field by averaging the results from analysis of soil samples randomly gathered around the acreage. Then the entire field was treated based on the average analysis. This approach of treating a whole field on the average made fertilizer recommendations and applications very simple. Only one rate of fertilizer was applied. With new precision farming technologies that allow changing fertilizer rates on-the-go, fertilizer is only applied as needed at each spot in the field. This change in application methods has shifted the goal of soil sampling from measuring the whole field average to measuring the variability of soil properties throughout the field. The two most common methods that accomplish this are through grid sampling and soil type sampling.

Grid sampling involves dividing a field into square or rectangular sections of several acres or less in size. The grower gathers soil samples from each section and sends them to a laboratory for analysis. The objective is to better estimate the need for soil nutrients on a scale smaller than the entire field.

Soil type sampling involves sampling sections of the field that have similar soil types. A grower uses soil survey maps to select sampling locations. Several samples are combined from each area of different soil type. This method results in samples being taken from different spacings around the field.

Dr. Robert Stephenson (driver) discusses soil sampling collection with Dale Leikam, Farmland Industries. The white ball mounted on top of the front platform is a GPS receiver that allows for the determination of a location by measuring the distance from several satellites in space.	Field information from the soil sampling locations is imported into AgInfo software for correlation with the soil sample results.
The learning process takes place in the field. "Hands-on" data collection will enable students to become trained for the 21st century. Students learn how to lay out grids and drive field boundaries.	Students determine correct locations for soil sampling, interpret on-board computer information, and make in-field decisions regarding data information
Students learn how to generate soil maps in the field, import and export data to take back into the classroom, and the procedures for taking soil samples.