Pettiet Ag Services Incorporated (PASI) was founded in 1973 by Dr. Joe V. Pettiet in order to provide detailed soil test information to growers in the Mid-South.

Long before the use of GPS technology in agriculture, PASI developed a method of grid sampling on a 10-acre grid size using aerial imagery and NRCS standard soil surveys. With our soil test data we were able to partition areas within fields that had varying needs. Early report maps were hand-drawn and the data and recommendation maps were hand-written.

GIS/GPS Technology
In 1984, Clinton Pettiet joined his father in the business and began to implement the use of Geographic Information Software (GIS) to prepare reports. In 1995, he began developing a new method of GIS, mapping field boundaries and developing sampling plans for growers using GPS receivers.

The GPS allowed the method of locating sample points to convert from the old “dead reconing” method to actual projection coordinates. This allowed us to create sample grids at a grid intensity determined by the grower and specific to the data set.

First in New Testing Methods
Clinton met with equipment manufacturers who were building single bin and multiple bin fertilizer and limestone spreading equipment. Working with their software developers, he found a way to use Pettiet Ag data to create prescription maps for soil amendment applications that can be applied variably across a field.

Soon afterwards, Clinton met with area fertilizer dealers and presented this totally new concept of variable rate application. Within the year a number of applications were available in the Mid-South.