446 



FIELD CROPS 



shaped potatoes so much desired for the market, of the type 

 shown in Fig. 138. The sweet potato will grow in very poor 

 soils, though it will yield better in those of moderate fertility. 

 The land should be rich enough to produce a good growth of 

 vines and foliage, but too much manure or too rich soil will 

 tend toward the production of a heavy top growth with only 

 a few small, undesirable potatoes. The quantity of commer- 



Fig. 138. The type of sweet potato plants suitable for setting. 



cial fertilizer which is ordinarily used is small, only from 200 

 to 500 pounds to the acre. The use of crimson clover or 

 some other legume in the rotation is desirable to furnish the 

 necessary vegetable matter in the soil. 



586. Growing the Plants. Sweet potatoes are ordinarily 

 grown from sprouts from the roots rather than by planting 

 the roots themselves in the field, though this latter practice 



