Precision Agriculture and GIS

Modern farming is about optimizing agricultural production. In this aspect, nothing has changed for thousands of years. Farmers have always been aware of striking a balance when applying inputs that increase crop yields but incur costs and reduce the eventual value of their harvests. So what has changed?

Ever increasing acceptance of information technology in everyday life has had an impact on farming, and this will only grow with increased accessibility. Perhaps the most influential development to expedite technology transfer to agriculture has been the development of GPS. By incorporating GPS into standard farming practices, farmers, researchers, and consultants have been able to improve the precision of existing agronomic management activities by implementing them at a subfield scale. Precision farming and associated variable rate technologies have been the result. Potentially, factors that influence crop productivity can be identified, mapped, and used to provide an implemented solution.

Added field level precision opens the way to better manage natural in-field variations where previously, in terms of treatments, a field was normally assumed to be homogenous. Of course, the farmer working on the field would have had "inside" knowledge of the field, but this information is not always transferable, and those without experience would have had to rely on imprecise management practices. This heightened awareness and ability to map more precisely has enabled the agricultural sector to implement important spatial tools in a GIS.

Precision farming (PF) and variable rate technologies (VRT) use spatial databases within field environmental and management variables with the aim of evening the application of field inputs while maximizing production across a field. Data is collected in a variety of ways, from handheld computers connected to a GPS unit using ArcPad to mobile georeferenced sampling hardware such as tractors and combine harvesters. Once mapped, this data, which can include soil characteristics, pest locations, drainage systems, and previous harvest yields, can be used to formulate a location-based prescription for the field management in the coming year. Much of the functionality to do this is offered by ArcGIS and ArcView 3.x and their associated software extensions—ArcGIS Spatial Analyst, ArcGIS Geostatistical Analyst, and ArcView Image Analysis. These extensions provide the farm manager the tools to interpolate data surfaces from point information, calculate the probability of certain agronomic events such as unfavorable climatic events, and incorporate satellite data concerning land use or live weather reports.

Precision farming relies heavily on the spatial analysis embedded in GIS. As the costs of modern agricultural practices continue to grow as a result of natural resource price increases, more agricultural legislation, greater environmental awareness, and the need to feed burgeoning human populations, so will the need to optimize agricultural management through the utilization of GIS.