Agroclimatic classification of the semi-arid tropics. I. A method for the computation of classificatory variables.

REDDY, S. J.; S. JEEVANANDA REDDY, Consultor CPATSA.

Agroclimatic classification of the semi-arid tropics. I. A method for the computation of classificatory variables.

1983

REDDY, S. J. | S. JEEVANANDA REDDY, Consultor CPATSA.

A simple method based on rainfall (R) and potential evapotranspiration (PE) for deriving variables to classify the semi-arid tropics into relevant agronomically homogeneous zones in suggested. A term 'available effective rainy period' is introduced for this purpose. The available effective rainy period is defined as the number of consecutive weeks in which the 14-week moving average of R/PE is >ou= 0.75, but for the initial week the value of R/PE is >ou= 0.50. The preceding week is taken to be the week of commencement of the sowing rains. The method permits estimation of weet and dry spells during the available effective rainy periodo and an estimate of the likely percentage of cropfailure years. These selected parameters allow a more relevant and realistic assessment of the agroclimatic environment and agricultural production potencial of a selected location or region.

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