INTRODUCTION 



Agricultural iMeteorology is defined as meteorology con- 

 ducted in the interest of agriculture. It considers the effect of 

 the weather conditions upon the development and yield of the 

 different crops. It is a branch of phenology. 



Phenology is defined as the branch of meteorology or of 

 biology that treats of animal or plant life and development as 

 affected by climate." 



Agricultural climatology is that branch of agricultural 

 meteorology which shows the effect of climate upon the geo- 

 graphical distribution of vegetation and the adjustment of farm 

 activities. This is the science that is considered in classifying 

 the vegetation of the globe into great botanical groups or belts, 

 as it is affected by the varying intensities of temperature, sun- 

 shine, and rainfall. 



Natural vegetation has adjusted itself to these climatic fac- 

 tors through long ages of selection, until it is possible to refer 

 to certain well defined locations where any certain tree or shrub 

 maintains its best development, other sections where it has a 

 constant struggle for existence, and still others where it is never 

 found. 



CULTIVATED PLANTS 



While man is constantly trying to grow crops in regions not 

 indigenous to them and indeed not well adapted to them, it will 

 be found that the main standard crops are grown in the region 

 and in the manner best suited for their best development. 



The great law of the survival of the fittest applies in crop 

 management as in everything else, and the farmer has uncon- 

 sciously adjusted his activities to the best crop and applies his 

 labor on it in the proper season for producing the largest yield 

 in the best condition. This relates, of course,, tO' the staple crops 

 in a district that has been occupied long enough to have the crop 

 distribution properly adjusted. 



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