152 THE FARMER OF TO-MORROW 



the semi-tropical arid climate. In Southern 

 Florida we have the semi-tropical humid cli- 

 mate. Over the country as a whole we have 

 from more than 60 inches to less than 10 

 inches of rainfall and a range in mean tem- 

 perature of more than 70 degrees F. to less 

 than 40 degrees F. The elevation of our 

 arable lands varies from below sea level to 

 6,000 feet above. We also have varying types 

 of rainfall; the greatest precipitation may oc- 

 cur in the winter months or may come in the 

 summer months. We have the greatest differ- 

 ences in relative humidity and sunshine. We 

 have differences in the range of temperature 

 both seasonal and daily, and we have differ- 

 ences in the length of the growing season. 

 Finally we have differences due to slope, ex- 

 posure, large bodies of water, and other in- 

 fluences too subtle for us to measure, 

 which may determine the special fitness 

 of the soil for a particular grade or quality of 

 product." 



He shows that with variations of rainfall 

 with intervals of 10 inches and variations of 

 temperature with intervals of 5 degrees we 

 have forty-six combinations of these two fac- 

 tors alone, which may affect crop development 

 and influence the utilization of soils. He pro- 

 ceeds : 



