SWEET-POTATO 437 



answer this purpose well, if so grown as to keep down the 

 growth of weeds. One of the best means of supply- 

 ing both humus and nitrogen consists in growing a pre- 

 ceding catch-crop of crimson clover, to be plowed under 

 in April as a preparation for sweet-potatoes. The clover 

 seed can be sown among the bearing cotton plants in Sep- 

 tember, taking care to inoculate the soil, which is usually 

 done by sowing with the seed some soil from a spot where 

 any true clover, such as crimson, red, or white clover, 

 has recently grown and developed tubercles on the roots. 



408. Effect on land. The large quantities of manures 

 and fertilizers sometimes employed for sweet-potatoes 

 tend to make this field produce good crops the next year, 

 provided the vines be left on the land and somewhat evenly 

 distributed. However, the sweet-potato in itself is an 

 exhaustive crop on account (1) of the large amounts of 

 potash and nitrogen removed and (2) of the leaching of 

 the soil by winter rain, which is apt to be especially great 

 on a field plowed in the fall and left bare of vegetation 

 during winter. To prevent this leaching, it is advisable, 

 where practicable, to sow small grain or some winter 

 cover-crop after harvesting sweet-potatoes. 



However, unless the field is securely fenced, stray hogs, 

 rooting for the small potatoes, will often destroy the stand 

 of any winter-growing plant. An additional reason for 

 selecting a fenced field for sweet-potatoes is in order that 

 the small, injured roots may be utilized by the landowner's 

 hogs, without the expense of handling this unsalable part 

 of the crop. 



It is generally advisable not to grow sweet-potatoes for 

 two years in succession on the same land. This is partly 



