THE GROWTH OF THE ROOTS OF PLANTS. 163 



water, and offers an obstacle to the deeper penetration of 

 the roots of crops. 



The presence of oxygen is indispensable in the soil wher- 

 ever the roots of plants may go. It is or should be obvious 

 to the intelligent reader that the more of the soil that can 

 be occupied by the roots of a crop, the better for the crop, 

 for it extends the feeding ground. It is something like 

 opening asecond field, by removing a fence, andthrowingit 

 open to a herd of cows or a flock of sheep. It increases the 

 food supply proportionately, and as plant food is always be- 

 ing carried down into the lower soil by the water, the far- 

 mers desire should be to give the roots of his crops the ut- 

 most facility for extending themselves in their search for 

 food. Roots are very enterprising in this way, and farmers 

 cannot do better than take a lesson from the instincts of the 

 plants which they cultivate. Wheat, which is considered 

 a shallow rooted plant, has been known to send its roots 

 down 8 feet into the subsoil. The author has traced the 

 roots of corn in a deep washout nearly 10 feet from the sur- 

 face; clover sends its roots down 10 or 12 feet; lucern a 

 most eager feeder and consequently exceedingly productive 

 has been known to extend its roots 18 feet down into the 

 subsoil. Common grass roots often go down 3 or 4 feet in the 

 soil where inducements in the shape of available food are 

 given. No doubt these are exceptional cases, but they 

 show what plants will do in their search for food, and in 

 every case these deep rooted plants are the most vigorous in 

 growth, proving that their purpose in sending down their 

 roots was successful. Where these roots went there were 

 air, and oxygen, and carbonic acid with it; and had not 

 the soil been porous and accessible to these nutritious gases 

 the roots could not have penetrated into it. It is not nec- 

 essary to break up the soil to this depth ; all that is needed 

 is to break up the crust under the surface, by running the 

 subsoil plow a sufficient depth under the first furrow, to let 

 in the air and open a way for the rains to enter freely, and 

 to permit both air and water to pass and repass, under the 

 influences of heat, and expansion and contraction, with the 



