ROOT SYSTEMS OF TRUE-PRAIRIE SPECIES. 



41 



Table 3. — Water-content of soils in excess of the hygroscopic coefficient at the upland and 

 lowland stations in the true prairie at Lincoln during 1919. 



1 The soil had been no drier at any time since May 5. 



2 Samples taken a few days after heavy rains. 



low prairie areas yield data which indicate that the root development 

 is not so extensive in the more moist lowland soil. This is of consid- 

 erable interest in itself and is especially significant, since many crop 

 plants are found to respond to these different environments in a similar 

 manner. Thus the root development of the natural vegetation may be 

 used as an indicator of the development of those of crop plants. The 

 data on root habits of prairie species are summarized in table 4, while 

 those of cultivated crops are discussed in Chapter VII. 



Table 4. — Root development of grasses on low and high prairies. 



