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. 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.