296 THE SMALL GRAINS 



THE CEREAL PLANT COMMUNITY 



319. Plant ecology. The study of a cereal crop is 

 fundamentally a study in plant ecology. It is much more 

 extended, however, than the latter, as ordinarily consid- 

 ered, because of the tremendous influence of human 

 agencies. 



Native plants commonly group themselves into associa- 

 tions, comprising but a few species, but many individuals 

 of each, in certain localities or over rather extensive uni- 

 form areas, where conditions of environment are favor- 

 able for these particular species. In such cases, the 

 individuals of a species exhibit characters considerably 

 different from those possessed by more isolated indi- 

 viduals in other places. The crowded individuals may 

 become dwarfed, etiolated, slender, or may possess small 

 (especially narrow) leaves, or small seeds which mature 

 quickly. 



320. Agronomy or study of the crop. If now human 

 agencies intervene to put individuals of the same species 

 under cultivation and therefore out of competition with 

 other species, then, aided by soil tillage, regular seeding, 

 and perhaps fertilizers or irrigation, the differences in 

 characters of these individuals from those of individuals 

 more isolated will be still greater, but in the other direc- 

 tion of larger size and better quality. Cereal crops, 

 because of the mutual protection of crowded individuals 

 and the favorable environment given them through cul- 

 tivation and soil adaptation, will succeed under condi- 

 tions so severe that the same individuals, if isolated and 

 without cultivation, could not survive. On the other 

 hand, the individuals of a crop must also compete with 

 each other, sometimes to their disadvantage. They 



