This document provides an overview of precision agriculture and the role of geographical information systems (GIS) in agriculture. It discusses how GIS allows storage, display, manipulation and analysis of geospatial data. A practical study is described where soil samples were taken from a field using GPS, analyzed for pH and EC, and entered into a GIS database to create maps showing spatial variation in these soil properties. The maps reveal differences in elevation, pH, and EC that can help inform crop selection and management practices tailored to different areas of the field.

1. Practical Report on,
Geographical Information
Systems
Precision Agriculture
32nd Batch
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2. Page of contents
Introduction
What is Precision Agriculture? 3
What is Geographical Information System? 3
What GPS can do? 4
The Role of GIS in Agriculture 4
Practical
Material and equipment 5
Methodology 5
Data 5
Soil sampling and mapping 6
Data analysis 7
References 9
Introduction
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3. 1. What is Precision Agriculture?
Precision Agriculture is the application of technologies and principals to manage spatial and
temporal variability associated with all aspects of agricultural production for the purpose of
improving crop performance and environmental quality.
2. What is Geographical Information System?
A geographic information system (GIS) integrates hardware, software, and data for
capturing, managing, analyzing, and displaying all forms of geographically referenced
information.GIS allows us to view, understand, question, interpret, and visualize data in
many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports,
and charts.
A GIS helps you answer questions and solve problems by looking at your data in a way
that is quickly understood and easily shared.GIS technology can be integrated into any
enterprise information system framework.
GIS Map 1
GPS receiver 1
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4. 3. What GIS can do?
Storage of data
Display data
Manipulation of data
Statistical application
Handling of missing data
Comparison of maps
4. The Role of GIS in Agriculture
Spatial analysis, the study of geographic features, and the relationships that exist between
them can be applied to many areas of the agriculture industry. By better understanding how
features within the landscape interact, decision makers can optimize operational efficiency
and improve economic returns. Regardless of scale-whether at the farm field level analyzing
crop yield information or across an entire country-GIS is becoming fully integrated and
widely accepted for assisting government agencies to manage programs that support farmers
and protect the environment. These are the agriculture GIS application in the field
Combining agronomic and economic data sets
Field data interpolation
Decision support for farm management
Farm asset allocation
Field input reporting
Regulatory compliance
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5. Practical
Material and equipments
GPS receiver - to get positional coordinates
Lord soil Sampler- to get soil samples
Sampling bags- to collect soil samples
pH meter –to measure the soil pH
EC meter –to measure the soil EC
GIS software/ computer/ user interface- to develop map
Methodology
As a group all the students of precision agriculture went to a selected bare field of
faculty. Then we were separated to small groups. Soil samples with depth of 10 inches and 20
inches below from soil surface were taken. Meantime we collected the longitudinal and
latitudinal data of the positions which soil samples were taken.
Then we went to the engineering department’s laboratory and measure the pH and EC
of the soil samples. These data were entered to database and also they feed to the GIS
software, ARC VIEW. Finally soil sample map was developed.
Data
Arc view
ID NO N E pH10 EC10 PH20 EC20
1 0095897 0177419 5.88 22.7 5.50 17.4
2 0095903 0177429 6.02 18.0 6.04 12.8
3 0095899 0177432 7.50 20.7 6.40 19.7
4 0095904 0177426 6.18 16.3 6.28 12.7
5 0095912 0177420 6.55 26.9 7.65 18.4
6 0095927 0177445 7.74 28.0 7.75 24.0
7 0095925 0177433 8.13 30.0 7.83 29.0
8 0095910 0177446 8.90 23.6 8.60 18.6
9 0095929 0177461 8.13 31.3 7.93 38.3
10 0095950 0177444 8.13 39.7 7.73 28.8
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6. Soil sample mapping
Elevation 1
EC-10 EC-20
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7. Data analyzing
Arial Photograph of faculty
Red circular area shows the field which practical was done.
Soil pH @ depth of 10cm Soil pH @ depth of 20cm
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8. DATA analysis
Importance of elevation
This map shows the elevation of the site selected. If this is a large field we can select
the crops according to the elevation. But this selected area is very small and elevation only
varies between 27m-44m. Therefore we can select one common crop which is suitable for
low lands for the whole field.
The importance of the elevation map of this small field is we can apply the
management practices according to the elevation. Specially we can apply soil conservation
measures in the areas where the contour lines are present in more closely.
Importance of soil pH
A pH reading is a measurement that expresses the degree of acidity or alkalinity, very
much like heat and cold are expressed in degrees Centigrade or Fahrenheit. The pH scale has
14 units and is centered on 7, which is neutral. Levels below 7 are considered in the acid or
sour range and readings above 7 are alkaline or sweet. Soil nutrients are at their optimum
availability in the range between 6 and 7. Most plants grow best in this range, although some
type of plant growth can take place anywhere between 3.5 and 10. The pH level greatly
affects the fertility of soil and quality of plant growth.
Under alkaline conditions, the solubility of minerals decrease to the point that nutrient
deficiencies occur. Plant growth is therefore limited by deficiencies in iron, manganese, zinc,
copper and boron. Phosphorus is also less available in alkaline soils and high levels of
calcium may inhibit the uptake of potassium and magnesium.
Under acidic conditions, many soil minerals dissolve and increase the concentration
of metal ions to toxic levels. The primary toxic metal is aluminum, but high levels of
manganese and iron can also inhibit plant growth under these conditions. The nutrients
phosphorus and molybdenum are less available in acidic soils and calcium and/or magnesium
may also be deficient.
In this field South area is more acidic and North area is more saline. Therefore we can
consider the most suitable crops for the field according to this ph map. Acid tolerance crops
are more suitable for south area and salinity tolerance crops are more suitable for north area.
Also if there is any crop available, we can manage soil ph according to that crop’s
requirements by changing soil ph. (by adding acids or bases.)
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9. Importance of soil EC
Soil electrical conductivity (EC) is a measurement that correlates with soil properties that
affect crop productivity, including soil texture, cation exchange capacity (CEC), drainage
conditions, organic matter level, salinity, and subsoil characteristics. By agricultural
standards, soils with an EC greater than 4 dS/m are considered saline.
We can clearly observe the variance of soil EC in this field with the maps developed.
References
Korte B. George, THE GIS BOOK, 5th Edition, 2001-by Onward press-Canada
ISBN- 13: 978-0-7668-2820-9
-10:0-7688-2820-4
http://www.gis.com/content/what-gis
http://en.wikipedia.org/wiki/Geographic_information_system
Special Thanks for Mr. Amila Buddhika ( demonstrator of Agric Engineering dept) for his
kindness Guidance and cooperation throughout this practical as well as developing maps with
GIS.
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