Precision agriculture is an excellent example of a range of technologies that have come together to offer farmers across a range of agricultural systems benefits to their crop management processes. The horticulture industry however has been slower to take up these technologies due to the smaller scale of our farms and the enormous variability across our growing systems (eg. regions, climatic influences, range of plant physiology – orchards vs plantations vs field crops vs protected cropping, seasonality requirements, etc). However the industry is now showing strong signs of interest to learn from these other industries, and apply these lessons to their own horticulture crops. For this reason, precision agriculture is considered a relevant and important emerging technology to horticulture.

Precision agriculture/farming assumes the existence of in-field variability. By using global positioning (GPS), a range of sensors (eg. soil, plant, weather), satellites or aerial images, information management tools (GIS) to assess and understand variations, information can be collected that can enable a grower/farmer to more precisely evaluate optimum sowing density, estimate fertilizers and other inputs needs, and to more accurately predict crop yields. It seeks to avoid applying inflexible practices to a crop, regardless of local soil/climate conditions, and may help to better assess local situations of disease or lodging.

The most common use to date of precision agriculture has been in allowing a grower/farmer to vary the rate of fertilizer across a field according to the crop’s need identified by GPS guided Grid Sampling. Fertilizer that would have been spread in areas that don't need it can be placed in areas that do, thereby optimizing its use.

Precision farming may be used to improve a field or a farm management from several perspectives:

• agronomical perspective: adjustment of cultural practices to take into account the real needs of the crop (e.g., better fertilization management)
• technical perspective: better time management at the farm level (e.g. planning of agricultural activity)
• environmental perspective: reduction of agricultural impacts (better estimation of crop nitrogen needs implying limitation of nitrogen run-off)
• economical perspective: increase of the output and/or reduction of the input, increase of efficiency (e.g., lower cost of nitrogen fertilization practice)

Other benefits for the grower/farmer may be to help establish a history of farm practices and results, in order to help in decision making and traceability requirements (as increasingly required in developed countries).1

Source:
1.  http://en.wikipedia.org/wiki/Precision_agriculture (dated 17 August, 2009)