Over the years soil fertility declined due to several factors.
It can be attributed to over application of inorganic fertilizer;
soil erosion, depletion of soil nutrients due to continuous tillage
and lack of information on soil characteristics.
Aware of this problem on soil fertility, the Department of Agriculture
in Bicol, conducted test on the capacity and limitations of Bicol
soils. The study focused on rice production areas particularly
the rice cluster farms covered by the GMA Rice production program.
In the past, soil test kits (STKs) were provided free to LGU
technicians, NGOs and farmers to determine the fertilizer requirement
of these cluster areas. The data gathered were turned over to
the Regional Soils Laboratory (RSL) initially as reference for
Today, the RSL together with the LGUs has come up with site
characterization or profiling. Soil characterization is one method
to determine soil fertility. Hence, farmers can now practice
judicious use of fertilizer in a particular soil by referring
to the soil maps.
In order to carry out soil characterization the DA used the
Geographical Information System (GIS) technology in site mapping.
The technology on GIS particularly the Global Positioning System
(GPS) instrument and the data gathered from STK results were
used to characterize and map rice farms in the region indicating
the fertility level. Acidity or alkalinity, macro and micro nutrient
status, fertilizer utilization status, important land features
and other relevant land-base information necessary in understanding
the capacity and limitation of these areas.
How GPS works
The GPS is a fully-functional satellite navigational system.
It is a vital global utility for modern navigation on land, sea
and air around the world and an important tool for map-making
and land surveying. It provides an extremely precise time reference,
required for telecommunications and some scientific research,
including the study of earthquakes. On the ground any GPS receiver
contains a computer that calculates its own position by getting
time signals from three of the four satellites, using a process
called trilateration (similar to triangulation). The result is
provided in the form of a geographic position longitude
and latitude to, for most receivers, within 100 meters.
Some specialized GPS receivers can also store data for use in
Geographic Information System (GIS) and map making.
Methodology of the project
The initial activity of the project was to identify/profile
rice production areas. Physical and biological aspects were quickly
determined using existing reports and maps. Information like
coordinates, elevation and other satellite data were collected
using GPS instrument. Soil properties using the STK and laboratory
results were determined and presented in graphs and maps. Meanwhile,
soil samples were collected in different rice production farms
in coordination with the LGUs and farmer association. A briefing
was also conducted to discuss the details of the activity and
the protocol including the use/operation of the GPS instrument.
The areas for profiling were identified and masterlisted in the
GMA Rice Program. Important characteristics of these areas taken
by the BSWM and the Regional Soils Laboratory (RSL) were gathered
for use in mapping soil characteristics.
The project specifically collects information on the location
of the farm, sampling sites, name of farmers, soil pH, NPK levels
and other relevant data. The GIS map developed using the GIS
software contains result on soil pH, available N, P and exchangeable
K, micro nutrients such as Iron (Fe), Copper (Cu), Zinc (Zn)
and Manganese (Mn) levels and the NPK levels were developed using
the GIS software.
Meanwhile, the fertility maps produced were practical and user-friendly
emphasizing the STK results indicating low, deficient and high
instead of numerical values like 1.0%N, 5% etc. where farmers
seldom understand. The fertilizer recommendations for different
rice production farms were also mapped based on soil characteristics.
In order to validate the effectiveness of the recommended fertilizers
a calibration or correlation with existing yield results will
be conducted in selected areas through techno demo research.
Who will benefit from the maps
The different maps generated will serve as guide for technicians
and farmers on the effective management of their farms by using
the right kind and amount of fertilizers. To come up with a more
complete and reliable result massive soil sampling is being done
in all the six provinces of the region. Information campaign
on how to collect soil samples are being done to create awareness
among farmers and technicians. Furthermore, the STK results are
also validated in the laboratory in order to come up with an
Assistant Regional Director for Operations and Regulatory, Jose
V. Dayao said that with the available maps, and corresponding
fertilizer recommendations, the farmers would save much from
fertilizer as they would be applying the right amount thereby
minimizing excesses or over usage. He also added that the results
are important for policy makers and the DA in particular in order
to effectively implement the rice program in the cluster areas.
He also suggested that same study be conducted for other commodities
and come up with maps up to the farm level.
of the Department of Agriculture RFU 5
October - December 2006
Vol. 15 No. 4