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Global Positioning System (GPS) in Precision Agriculture
U.K. Shanwad, V.C. Patil, G. S. Dasog, C.P.
Mansur and K. C. Shashidhar
Department of Agronomy, University of Agricultural Sciences
Dharwad - 580 005. Karnataka, India
shanwad@rediffmail.com
The growing food demands due to ever-rising human populations forced world farmers to adopt resource-intensive and unsustainable practices that increased both economic and environmental costs. Developing countries farming systems, therefore, present both obstacles and opportunities for adoption of precision agriculture. Tailoring soil and crop management to match varying conditions (soil texture, moisture, nutrient status and pest distribution) within a field is not entirely new to farmers. The growers traditionally noted yield variability in space, time and changed farm practices depending on site conditions to optimize soil resources and external inputs. This was possible because most developing countries farms were relatively small and farmers were familiar with spatial and temporal variation. However, the precision farming in terms of using technologies such as Global Positioning Systems (GPS), Geographic Information Systems (GIS) remote sensing, yield monitors, guidance systems for variable rate application to manage within-field variation is still in its infancy in almost all developing countries including India (Srinivasan, 1999). Precision agriculture is an integrated crop management system that attempts to match the kind and amount of inputs with the actual crop needs for small areas within a farm field. Precision agriculture is often referred to as GPS (Global Positioning System)- based agriculture, variable-rate farming, prescription farming, site-specific farming etc.
The need for Global Positioning System (GPS)
Global positioning system has revolutionized positioning concept, though it started primarily as a navigation system. Today, the Global Positioning System (GPS) has become an international utility. In addition to its ease of use and worldwide all-weather operation, GPS owes its popularity to the dependable high accuracy with which position, time and direction can be determined. (Ajai, 2002). As a tool of precision Agriculture, Global Positioning System satellites broadcast signals that allow GPS receivers to calculate their position. This information is provided in real time, meaning that continuous position information is provided while in motion. Having precise location information at any time allows crop, soil and water measurements to be mapped. GPS receivers, either carry to the field or mounted on implements allow users to return to specific locations to sample or treat those areas.
GPS role in Precision Agriculture
Precision Agriculture is doing the right thing, at the right place, at the right time. Knowing the right thing to do may involve all kinds of high tech equipments and fancy statistics or other analysis. Doing the right thing however starts with good managers and good operators doing a good job of using common tools such as planters, fertilizer applicators, harvesters and whatever else might be needed. (Colvin and Kerkman, 1999).
In this context, GPS becomes part and parcel of precision agriculture. For analysis and processing of remote Sensed images requires ground truth information, collected in the field, at a variety of sites and often at various times throughout the crop production season. Conventionally this data has been manually recorded on field sheets, air photos or paper maps and considerable time and effort is required to convert it to digital format for use in remote sensing or GIS. For image analysis the ground data must be digitized in order to create a mask for training the software to recognize different conditions and classify the remote sensing imagery. We have developed an interactive, portable system to record field data directly into a digital database consisting of yield, soil, road, water and contour maps overlain on air photos or remote sensing imagery. A GPS receiver is linked to a note book computer displaying appropriate, pre loaded information layers, and a software package then combines incoming GPS signals with the displayed data to allow the user to see where they are with respect to the map components. The various layers of information can be easily edited and modified in the field and new data can be added as point or polygon layers and attribute tables. (Mc Govern et al., 1999).
The system also allows the user to save GPS data to view and track field activity at a later date. Data recorded in the field, such as the location of weed patches, field boundaries and crop condition noted can be moved easily to other GIS. Spreadsheet and image processing systems to enhance datasets and improve analysis. The image classification process in particular can be improved with the accurate and easily accessible ground-truth data.
Precision Farming at a Glance-Steps
Involved
Strategy Formulation and Impact of Precision Farming
System Elements of Precision Farming
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