1. Global positioning system
GPS is a set of satellites that identify the location of farm equipment within a meter of an actual site in the field. The value of knowing a precision location within inches is that:
• Location of soil samples and the laboratory results can be compared to a soil map.
• Fertilizer and pesticides can be prescribed to fit soil properties (clay and organic matter content) and soil conditions (relief and
• Tillage adjustments can be made as one finds various conditions across the field and
• One can monitor and record yield data as one goes across the field.
The GPS technology provides accurate positioning system necessary for field implementation of variable rate technology. The
present internet makes possible the development of a mechanism for effective farm management using remote sensing.
2. Geographical information system (GIS)
A geographical information system (GIS) consists of a computer software data base system used to input, store, retrieve, analyse and display, in map like form, spatially referenced geographical information.
3. Grid sampling
Grid sampling is a method of breaking a field into blocks of about 0.5-5 ha. The sampling soils within those grids to determine appropriate application rates. Several samples are tkan from each grid, mixed and sent into the laboratory for analysis.
4. Variable rate technology
Variable rate technology (VRT) consists of farm field equipment with the ability to precisely control the rate of application of crop inputs that can be varied in their application commonly include tillage, fertilizer, weed control, insect control, plant population and irrigation.
5. Yield monitors
Yield monitors are crop yield measuring devices installed on harvesting equipment. The yield data from the monitor is recorded and stored at regular intervals alongwith positional data received from GPS unit. GIS software takes the yield data and produce yield maps.
6. Yield maps
Yield maps are produced by processing data from adopted combine harvester that is equipped with a GPS that is integrated with a yield recording system. Yield mapping involves the recording of the grain flow through the combine harvester, while recording the actual in the field at the same time.
7. Remote sensors
Remote sensors are generally categorized as aerial or satellite sensors. They can indicate variations in field colour that corresponds to changes in soil type, crop development, field boundaries, roads, water etc. Remote science in agricultural terms means viewing crop from overhead (from a satellite or low flying aircraft) without coming into contact, recording what is viewed and displaying the image and provide the map to pinpoint the field problems more earlier and more effectively. In remote sensing, information transfer is accomplished by use of electromagnetic radiation (EMR). EMR is a form of energy that reveals its presence by the observable effects it produces when it strikes the matter. Due to remote sensing we have been able to observe large regions suitable for agriculture, making use of sensors to measure energy at wavelengths which are beyond the range of human vision (ultraviolet infrared, etc.) and globally monitoring earth possible from nearly any site. Remote sensing technology can be used to provide valuable information on various
agricultural resources which influences production. Some of the broad agricultural application areas are:
- Crop production forecasting: It includes the identification of crops, acreage estimation and yield forecasting.
- Soil mapping: Soil maps afford the information on the suitability and limitation of the soil for agricultural production, which are helpful in selection of proper cropping system and optimal land use planning.
- Wasteland mapping: Information on degraded and wasteland e.g. salt affected areas, acidic soils, eroded soils, water logged area, dryland etc.
- Water stress: The use of remote sensors to directly measure soil moisture has had very limited success. Synthetic Aperture Radar (SAR) sensors are sensitive to soil moisture. SAR data requires extensive use of processing to remove surface induced noise such as soil surface roughness, vegetation and topography.
- Insect detection: Aerial or satellite remote sensing has not been successfully used to identify and locate insects directly. Indirect detection of insects through the detection of plant stress has generally been used in annual crops. Te economic injury level for treatment is usually exceeded by the time plant stress is detected by remote sensing entomologists prefer to do direct in field scouting in order to detect insects in time for chemical treatments to be effective and economics.
- Nutrient stress: Plant nitrogen stress areas can be located in the field using high-resolution colour infrared aerial images. The reflectance of near infrared, visible red and visible green wavelengths have a high correlation to the amount of applied nitrogen in the field.
8. Auto-guidance systems
Auto-guidance system allows farmers to maintain straight rows during farm operations and to come back to the same rows the next season. They allow more precise input application with these systems.
9. Proximate sensors
Proximate sensors can be used to measure soil (N and pH) and crop properties as the tractor passes over the field. The soil sample is scooped, pressed against an electrode, stabilization period of about 10-15 seconds allowed, and the reading taken.
10. Computer hardware and software
In order to analyses the data collected by other precision agriculture technology components and to make it available in usable formats such as maps, graphs, charts or reports, computer support is needed.
(Source – http://www.journalcra.com/sites/default/files/Download%20366.pdf)