Precision agriculture uses among other techniques the Normalized Difference Vegetation Index or NDVI. This index considers the development, quantity and quality of the vegetation. Its use dates back to the year 1973 when it was developed through satellite infrarred imagery, as a method to identify and locate areas of vegetation on the planet. Except in large areas of cultivation in the United States, Australia and other countries, the study of NDVI in agriculture had no sense for small farms until the appearance of the civil drone.

Now, with the light multispectral cameras and the development experienced by the sector of unmanned flight, a whole range of new possibilities has opened up for smaller operations that require greater precision images for the specific localization of problems in crops. Some of the applications are:

• Identification of crop varieties
• Count of plants
• Early identification of health problems
• Management of the use of fertilizers and plant protection products
• Design of irrigation systems adapted to the needs of the plantation
• Ecological benefit to the substrate of the plantation and the environment

Application in vineyards

Mallorca has a burgeoning wine market in expansion, which requires advanced solutions to produce quality wines in small tracts of crop and distinguished from wines produced in regions of more extensive farming. Imaging with drones allows to produce a map of the vineyard and identify areas of the crop with health problems and focus treatment. This can be useful also for experimentation with new varieties. It is possible to numerically quantify the production of chlorophyll in the new experimental planting and compare it with other data.

A recent study in Australia describes the economic benefit of using NDVI images in a plantation of 3.3 hectares producing only one wine at $ 19 per bottle. By selecting the highest quality vineyards and designing a collection plan, they offered a second better quality wine ar $ 30 per bottle. The winery grew next season benefits to $104.600 or $ 37,000 per hectare, increasing 19 percent annual profit. With the cost of the investment to obtain the NDVI orthomosaic, the return was 1200%.

Used properly by the manager and the winemaker at the vineyard, precision farming will achieve:

• Increase the economic return of the vineyard thanks to greater efficiency in management
• Improve gestion protocols
• Improve the quality of the grapes
• Increase the uniformity of the farming blocks
• Identify the qualities of the vineyards within a same block
• Improve the efficiency of the collection system, producing higher quality wines
• Improve efficiency in the sampling for tests

On the other hand, images taken in the visible spectrum can be used also for the production of 3D models of the ground of the vineyard, and measure the average height of the plants, produce high definition maps of the planting, or preparation of contourline maps for calculations of pressure in irrigation systems, etc.

Application in golf courses

In golf courses, management of water resources has a vital importance, both by the economic cost and environmental cost of irrigation and the associated public image. 3D modeling and quantification of the health of the grass with NDVI images are 2 excellent tools for the elaboration and design of more efficient irrigation systems and localize problems in the substrate thus focalizing treatment.

3D modeling of the field can become an innovative and attractive tool for promotion, since it allows to export the interactive model for incorporation into websites and smartphone applications, improving the user experience. The acquisition of high quality 2D mosaics is useful to elaborate large high quality maps of the fields, or to print contour line maps, offering the golfer greater information about the field and its difficulty before getting to it.