For production purposes, a chemical analysis of the soil should be conducted by using
representative samples from the different layers found in the test pits. In general, the
pH, available nutrients such as phosphorus, potassium, organic carbon and nitrate, etc.,
are determined by chemical analysis of soil.
2.1.6 Land
It should be confirmed that the proposed land area is suitable. The general
conformation of the land should be with slopes not steeper than 2 percent. If wasteland,
unsuitable for agriculture or other direct use, is selected for a project, the cost of the
land will be low. Land elevation and flood level are important factors in determining the
suitability of the area for the construction of a fish farm or hatchery. The land should be
free from deep flooding; the maximum flood level for the past 10 years should not be
higher than the top of the dikes. Observation of the marks left by flood waters on
bridges or other structures at the site, or questioning of local people, may give
information about the expected heights of floods. The shape and size of available land
should be considered: land with a regular shape and extensive enough for future
expansion is ideally suitable for a fish farm. It is very important to know the
development plans for the area as it would be unwise to select a site for a project in a
region where future industrial activity may cause air and water pollution. Similarly, if a
site is adjacent to a heavily populated area, the risk of pollution should be borne in mind.
However, some industrial and agricultural wastes may be utilized in fish farming. In such
cases, special investigations should be conducted on their utilization or required
treatment.Underground utilities crossing the site (oil pipelines, etc.) may render otherwise good
sites unsuitable for a project. Generally, high electric power poles, radio masts and the
like are not allowed in the pond area.
The type and density of vegetation depend partly on the land elevation. Vegetation is
also an indicator of soil types and of the elevation of the water table. The type and
density of vegetation, its size and the root systems of trees largely determine the
method of clearing the site and, therefore, the construction time and cost.
Grassland, abandoned paddy fields, open woodland or land covered with low shrubs
and bushes allow cheaper construction than land with very thick jungle or swampy areas
with high trees. However, in the cyclone belt or in areas where strong winds are
frequent, it is very important to have a wide and high windbreak of thick vegetation
against the direction of the prevailing wind.