CROP PRODUCTION 155 



course, great variation in the climate of the respective sections. 

 Northern Illinois receives an annual rainfall of less than thirty-five 

 inches, while the southern third of the state receives from forty to 

 fifty inches. Temperature variations for these areas are even more 

 striking than rainfall differences, and result in a marked change in 

 the length of the crop-growing seasons. At Fairfield corn may be 

 planted during the last days of April, while at DeKalb, May 18 is 

 the earliest date at which it can safely be planted. 



The soil survey, which is more than three-fourths completed, 

 shows how great a variation we have in our soil types. To date, 

 about one hundred and twenty-three types have been recorded. Such 

 extremes of soil type indicate clearly the complex nature of the crop- 

 production problem with which we have to deal. With such great 

 variation in soil type and climate as we have in Illinois, is it any 

 wonder that a man who is a successful farmer in southern Illinois 

 might be a failure in northern Illinois? 



A satisfactory solution of crop-production studies in Illinois must 

 be founded on a full knowledge of the soil and what is taking place in 

 it, as well as a complete understanding of the influence of climate and 

 the inter-relationship of these great factors as they affect plant growth. 

 Much has been done looking toward a proper solution of the soil prob- 

 lem, tho many vital questions remain unsolved. It will be some time 

 before plant studies have overtaken soil investigations, because the 

 former field remains largely untouched. 



Again, what are the outstanding problems which should be 

 attacked first? It seems to me that the fundamental crop problem 

 is "adaptation." If this is granted, what is the method of attack? 

 We believe the approach must be made through a study of plant 

 physiology. "The aim of plant physiology" as stated by the great 

 botanist Palladin, "is to gain a complete and thoro knowledge of all 

 the phenomena occurring in plants, to analyze the complex life pro- 

 cesses so as to interpret them in terms of simple ones and to reduce 

 them finally to principles of physics and chemistry." 



Little is now known of the sensitive or critical period in crop 

 plants in relation to environmental factors such as moisture, tempera- 

 ture, and light, as viewed from the physiological aspect, more partic- 

 ularly in its application to field conditions. The basis of attack, then, 

 must be the study of the relationship of environmental factors to the 

 various life stages of crop plants. These life stages or physiologic 

 phases may be grouped as follows : ( 1 ) the seed stage ; (2) the germ- 



