CHAPTER XV. 



PLANTS CULTIVATED FOR THEIR ROOTS, 



AND LEAVES. TURNIPS. (Brassica.) 



KOHL RABI. CABBAGE. RAPE. 



432. In Great Britain and Germany roots are grown to a 

 very great extent to feed stock, and to act, indirectly, as a reno 

 vator of the soil, in rotations. It is not yet a century, since the 

 present system of root culture was introduced, but it has entire 

 ly revolutionized Agriculture, and the Ail could not now be 

 profitably exercised without it. This class of plants is not nu 

 merous, and they owe their beneficial effect on the soil chiefly 

 to the fact that they are not allowed to seed. If they bear 

 seed, they cease to be &quot;fallow crops,&quot; and in their effects be 

 come similar to the cereals. They may be comprised in the 

 genera, (a,) Turnips, (including Cabbages;) (b t ) Potatoes; 

 (cj Carrots; (d,) Parsneps; (e^) Beets; (f,) Jerusalem Arti 

 chokes; (g,) Onions; (h,) Sweet Potatoes. Still more are culti 

 vated as garden plants. The climate of a great portion of the 

 United States is but illy adapted for the winter-preservation of 

 several of these roots; and this fact, together with our less 

 scientific and more careless mode of farming, has tended to 

 discourarge their cultivation. In the older States, however, 

 more attention is now being paid to this subject, and there ar 

 none of the above which may not be successfully and profita 

 bly cultivated in Michigan. The profit of a root crop is two 

 fold direct and indirect : direct, when we sell or so consume 

 the produce in feeding animals as to realize more money than 

 the production has cost us ; indirect, when our only profit is in 



