PRINCIPLES OF FARM PRACTICE 



How plants get water. If the roots of a young radish 

 plant which has been developed by placing seed between two 

 moist pieces of paper are examined, they 

 will be found to be covered with fine hairs. 

 These hairs are called root-hairs. They 

 are the absorbing organs of the roots. The 

 roots themselves absorb little water. 

 They serve to hold the plant in place. 

 They also furnish surface for the develop- 

 ment and distribution of root-hairs, in 

 much the same way that twigs and 

 branches of a tree afford surface for the 

 development and distribution of the 

 leaves. All the roots of a plant taken to- 

 gether are known as a root-system. As 

 roots grow in length new root-hairs appear 

 near the root-ends, while the root-hairs 

 farthest away from the ends shrivel up 

 and disappear. Thousands of little roots 

 of a vigorously growing plant push their 

 way into all parts of the upper layers of 

 the soil, where they develop root-hairs for 

 the absorption of water. In this way, 

 much of the capillary water in the region 

 of root growth is reached and supplied 

 to the plant. 



The extent of the root-system of a 

 plant can be realized only by carefully 

 measuring or estimating the total length 

 of all the roots. It has been estimated that if all the roots of a 

 nearly mature corn plant were placed end to end they would 

 extend about one thousand feet, and that those of certain 



Diagram ot root- 

 hair much enlarged. 



A . Cell or root from 

 which root-hair is an 

 outgrowth. 



B. Root-hair. 



C. Soil particle. 



D. Film of water 

 around soil particle. 



Arrows show path of 

 water through root- 

 hair. 



