Climatological factors in relation to dryland agriculture

Detailed statistical studies were made on climatological data pertaining to important dry farming research stations In India, and certain aspects of climate Investigated. Relationships among the climatological parameters were investigated. Rainfall distribution curves pertaining to long periods were examined for identifying regularities in the pattern of distribution, if any. Number of rainy days and annual rainfall ware closely correlated. Log monthly rainfall and log variability of rainfall were inversely correlated. Rainfall curve patterns indicated that the ascending and descending portions of the rainfall curve were very closely correlated. In the case of Kovilpatti, the magnitude of the ascending portion of the rainfall curve and the span of a sequence were very closely correlated. For Kovilpatti Centre wind velocity was established to be the best parameter for predictiug Piche's evaporation. In the many relationship patterns studied it was interesting to none that a single relationship pattern held good for a number of different places or years, in spite of the fact that the ranges of values for the data studied were quite wide. Thus the study of these data was simplified as a very few relationship patterns were sufficient for prediction purposes.