Semi-detailed Soil Survey of the LIuidas Vale Area, St. Catherine-St ...

DESCRIPTION OF THE SURVEY AREA
until December. Rainfall peaks are centered around October and June. The
annual R75/PET value for Ewarton is the lowest for all mentioned stations.
For the hills surrounding the basins no climatic data are available from
rainfall stations in the survey area. Based on the information of the Agroclimatic
zones map for Jamaica (SSU 1989i), rainfall should be higher and
PET should be lower than in the basins. Yearly R75/PET values will be
between 1.00 and 1.25 and the dependable growing period will extend for at
least eight months (May-December). The rainfall data from Point Hill are
chosen for the hilly part of the area (Appendix I).
A wide range of annual crops can be grown throughout the dependable
growing period provided their growing cycle matches the length of the
dependable growing period and the temperature is within the acceptable
range (see Section 2.2.2). Nevertheless, it should be avoided that crops are in
a stage sensitive to heavy rainfall in the months of October, September and
May.
Rainfall intensities are not measured in the survey area. Studies of rainfall
data from a wider range of stations in St. Catherine, more recent data and
analyses of longer records of data can be found in different publications (SSU
1987a, SSU 1989h, SSU 1989i).
2.2.2 Daily air temperature^
The daily air temperature, as presented in Appendix I and Table 3, is
calculated with linear regression equations, relating elevation above mean
sea level (msl) to minimum, mean and maximum day temperatures for all
months (SSU 1988a). Temperature requirements of the different crops are
defined in JAMPLES (see Chapter 5).
Ewarton which is located in the St. Thomas in the Vale basin at an elevation
of 260 m above msl. has temperatures varying from 17 °C (mean Tmin in
February) to 30 °C (mean Tmax in August), as can be seen in Table 3. The
Liuidas Vale basin at an elevation of approximately 370 m above msl is
represented by Worthy Park, has approximately the same rounded off
values for Tmin and Tmax, but the yearly mean temperature is lower.
Generally January to March are the coolest months and July to September
the hottest months. These periods coincide roughly with the driest and the
wettest periods respectively.
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