DEEPIKA SAHU, Department of Soil Science and Agricultural Chemistry
ANJALI PATEL, Department of Agronomy
Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh

*Techniques of remote sensing play an important role in crop management under precision agriculture and its application offers new opportunities to ameliorate various agricultural practice for managing plant disease practices, epidemiological information is utilized using a geographic information system (GIS).

*A GIS is a computer system designed to collect, store, manage, and display all types of geographical data referenced by geographic coordinates and can be installed on any recent model of desktop computer.

*Global positioning system (GPS) has the capability to record field data (slope, aspect, nutrients and yield) as geographically latitude and longitude data. Using GPS, one can determine and record the correct position of an object of interest without interruption; so therefore, it can provide a larger database to the user.

GIS in crop management
GIS applications for agriculture are developing rapidly and include generic commercial packages such as Arc View (ESRI, Redlands, CA) or MapInfo Desktop (MapInfo Corp., Troy, NY). Some other software packages have been introduced by AGRIS Corporation, Agri-Logic, Farm Works TM, John Deere Precision Farming Group, Case Corporation, RDI Technologies, and Rockwell International, have been developed. As with other types of computer software, compatibility between competing systems can be a problem, but data transfer protocols and generic data formats have been developed to work around this problem.

Some of the advantages of using GIS technology:
  • It has the ability of improving the organizational integration. GIS would then integrate software, hardware and also data in order to capture, analyze, manage and so display all forms of information being geographically referenced.
  • GIS would also allow viewing, questioning, understanding, visualizing and interpreting the data into numbers of ways which will reveal relationships, trends and patterns in the form of globes, maps, charts and reports.
  • Geographic Information System is to provide a help in answering questions as well as solve problems through looking at the data in a way which is easily and quickly shared.
  • GIS technology could also be integrated into framework of any enterprise information system.
  • And there would be numbers of employment opportunities.
  • Those are among the advantages that could be provided with the use of GIS technology. Considering the use of the said technology might be considered as of great decision to make.

Disadvantages of using GIS technology:
  • GIS technology might be considered as expensive software.
  • It as well requires enormous data inputs amount that are needed to be practical for some other tasks and so the more data that is to put in.
  • Since the earth is round and so there would be geographic error that will increase as you get in a larger scale.
  • GIS layers might lead to some costly mistakes once the property agents are to interpret the GIS map or the design of the engineer around the utility lines of the GIS.
  • There might be failures in initiating or initiating additional effort in order to fully implement the GIS but there might be large benefits to anticipate as well.

GPS in crop management 
The GPS consists of 24 satellites that circle the earth in six orbital planes having four satellites in each plane and associated ground stations. These satellites are distributed in a unique manner to ensure the coverage of the entire globe. GPS allows farmers to accurately navigate to specific locations in the field, year after year, to collect soil samples or monitor farm conditions. These satellites, known as NAVSTAR (Navigation by Satellite Timing and Ranging), have been launched and maintained by the Department of Defense (DOD) to provide all weather ranging 24 hours a day anywhere on the surface of the earth. Each orbit is at an altitude of 20,200 km (12,500 miles).
Handheld GPS units can be used to obtain land-mark coordinates such as irrigation wells, or road intersections which can then be used as reference points to digitize the hand-drawn detailed map for display with other layers referenced to the same coordinate system.

Advantages of GPS
  • The GPS signal is available anywhere on the globe. Hence user will not deprive of GPS facility anywhere.
  • There is no charge to utilize the GPS service as US Defense bears cost of GPS system. It is maintained and upgraded by US Department of Defense. It is cheaper compare to other navigational systems.
  • The GPS system gets calibrated by it's own and hence it is easy to be used by anyone.
  • It provides user with location based information. This will be helpful in various applications such as mapping (used in cars), location, performance analysis (used in sports), GIS etc. Example: Google Earth Application.
  • GPS helps find retail outlets in new visitor location.

Disadvantages of GPS
  • GPS chip is power hungry which drains battery in 8 to 12 hours. This requires either battery replacement or recharge.
  • GPS signal does not pierce through the solid walls or structures. Moreover it is affected by large buildings or structures. Due to this, user will not be able to utilize GPS service in indoors or under water or in dense tree regions or in underground stores or places etc.
  • GPS accuracy depends on sufficient received signal quality. GPS signal gets affected due to multipath, atmosphere (i.e. ionosphere), electromagnetic interference etc. This leads to error of about 5 to 10 meters in GPS signal.
  • It is better not to rely completely on GPS system. Backup travel maps with directions will help in the event of GPS system failure.

Remote Sensing in crop management
Remote sensing is the study of acquiring data about an item or region from a distance and without connecting physically with the article. This marvel has numerous applications like studying, photography, ranger service, topography and so on and noteworthy utilization of this strategy has been found in agribusiness part. The distant detecting methods utilizing topographical data framework, satellite advances, soil sciences and agronomy are utilized to expand the farming yield. There are various utilizations of far off detecting in the field of agrarian. The following is a synopsis of these applications.

1) Crop production

2) Assessment of crop damage and crop progress

3) Cropping systems analysis

4) Crop identification

5) Acreage estimation

6) Crop condition assessment and stress detection

7) Identification of planting and harvesting dates

8) Crop yield modeling and estimation

9) Identification of pests

10) Soil moisture estimation etc

Fig. Remote Sensing

Advantages of Remote Sensing:
Remote sensing has come a long way in recent years and is an impressive surveying technique with different advantages.
  • Remote Sensing Technology Can Survey Large and Inaccessible Areas.
  • Remote Sensing Data Can Have a Wide Range of Uses.
  • Point Cloud Software Analyzes Data Quickly .
  • Remote Sensing Doesn’t Disturb People or the Environment.

Disadvantages of Remote Sensing:
Unfortunately, nothing is without limitations, and remote sensing does have some disadvantages. While the advantages outweigh the downsides, it’s a good idea to consider the following cons of remote sensing before investing in this survey technique.
  • Remote Sensing Instruments Need to Be Calibrated.
  • High-Resolution Data from Remote Sensing Can Be Hard to Store.