ANNUAL REPORT. OF THE Off. Doc. 



THE PRINCIPLES OF PLANT FEEDING. 



By Prof. W. A. Buckhout, State Colleye, Pa 



The cultivated plants are derived from the wild; and in spite of 

 the changes which cultivation has developed and intensified, the gen- 

 eral principles of plant physiology apply to them. 



Plants stand between the mineral and the animal worlds. They 

 derive their food from the mineral, earth and the air, and in turn 

 become the food of animals. 



The roots of plants are specially fitted for establishing and main- 

 taining a close and intimate contact with the particles of earth. 

 They do this by their extensive ramification and, particularly, by 

 their root hairs which are delicate prolongations of individual cells 

 and are thus the active agents in the solution and absorption of the 

 food substances of the soil. 



The leaves are, correspondingly^, specially constructed so as to pre- 

 sent a large surface of contact with the air, and through their breath- 

 ing pores, some thousands to the square inch of the lower surface, 

 to take in the carbon dioxide of the atmosphere. Under the in- 

 fluence of sunlight and the green substance of the cells of the leaf, 

 carbon dioxide is decomposed, the carbon retained to be used in con- 

 nection with food substance derived from the roots while the oxygen 

 is returned to the atmosphere, thus restoring its purity and making 

 it better fitted for the use of animals. 



' The practical question is. How can the best conditions be main- 

 tained so as to secure the best growth of cultivated plants? 



The ground should be put in good mechanical condition and of 

 good fertility, so that the roots may penetrate freely and come in 

 close contact with food materials. Particularly should a liberal and 

 constant supply of water be maintained by irrigation, it may be, and 

 by cultivation and organic matter which conserve the water supply 

 by restricting its evaporation and loss. 



The aim should be to secure a rapid, continuous and vigorous 

 growth of plants. This will not only secure a better crop return, but 

 will also give more resistant plants which outgrow and ward off 

 weeds and diseases. 



