FERTILITY AND HUMUS IN DRY AREAS 421 



seem profitable to grow them for such a use. Promi- 

 nent among the non-leguminous crops that are grown 

 for burial are winter rye, buckwheat and Dwarf Essex 

 rape. Winter rye has peculiar adaptation for such 

 growth, since it can be sown in the autumn and buried 

 in the late spring without losing a crop the season that 

 it has been buried. It may be drilled in amid the stub- 

 bles and without discing them in the autumn. It may 

 be buried in the spring in time to follow with a crop of 

 corn or to summer-fallow the land as may be desired. 

 Buckwheat and rape may be grown for such a use on 

 summer-fallowed land. When thus grown the late sea- 

 son at which the crop is buried may to some extent 

 prove adverse to the retention of soil moisture, but this 

 will be probably more than offset by the benefits that 

 will result from the burial of one or the other of these 

 crops. Winter rye should be buried usually not later 

 than the earing stage, buckwheat at the stage of full 

 bloom, and rape when it has reached maximum growth. 



Alfalfa furnishes large supplies of organic matter 

 in the decay of its roots when the crop is broken by 

 the plow. The roots not only increase the plant food 

 content in the soil and subsoil, but they add greatly to 

 the moisture-holding power of the soil by the absorbing 

 power of the roots in their decay, and also by the many 

 small channels which they open up in the subsoil for 

 the downward passage of ground water. So beneficial 

 is the mission of alfalfa in this respect, that in dry areas 

 it may be wise to grow it in somewhat short, rather than 

 in long, rotations, so that the benefits resulting from 

 the humus which it supplies may be accelerated and 

 increased. 



The Canadian field pea is a most excellent humus- 

 supplying plant when buried in the soil, but to the burial 

 of a crop of peas there is the same objection that applies 

 to the burial of a crop of alfalfa, viz., that the pea crop, 



