A Botanical and Economic Study. 171 



CHAPTER V. 

 Agriculture — Physiological. 



THE cultivation of Indian corn has been greatly improved 

 within recent years. New machines have been devised 

 for drilling the kernel into the ground, and new culti- 

 vators of improved pattern have been introduced. It is not 

 essential, in describing the maize plant, to decide such ques- 

 tions as the merits of deep or shallow cultivation, the value 

 of removing the tassels as a means of increasing the yield, 

 the value of root-pruning, etc. These are questions of agri- 

 cultural practice and extra limital. 



This chapter will deal with practical physiological consid- 

 erations, such as the effect of fertilizers and the measures 

 necessary to restore soil fertility. The chemical changes 

 which the soil undergoes during plant growth, and the proper 

 rotation to be used in intensive agriculture will be discussed. 

 The object will be to investigate rather the principles under- 

 lying fundamental practices, and it is hoped that the results 

 will be of general and wide application. 



From experiments at Rothamsted, on a large number of 

 cereal and non-cereal plants, Messrs. Lawes and Gilbert have 

 deduced many important principles. The German stations 

 and the experiment stations of the United States also fur- 

 nish material at hand for a general agricultural survey. A 

 few general rules are given. 



It is certain that the increased growth of our staple starchv. 

 yielding grains is greatly dependent on a supply of nitrogen 

 in the soil. 1 The better the cereals are matured, the lower 

 is their percentage of nitrogen, the explanation being that 

 maturation means the greater formation of non-nitrogenoiiN 



1 Gilbert, J. II.. Agricultural Investigation, Rutgers College. X. J . 1SS4. 



