POTATOES 121 



gested by Johnson and Rosa for Eastern Virginia conditions: 

 Sweet potatoes, followed by crimson clover or rye ; followed by 

 early potatoes with late corn between the rows and rye or cow- 

 peas seeded between the corn at last cultivation; followed by 

 potatoes or any truck crop; followed by sweet potatoes. For 

 Arkansas conditions, AVicks suggests the following three-year 

 rotation: After the sweet potatoes are taken off, hogs are 

 turned on to pick roots, etc. The land is then ploAved and a crop 

 of corn with cowpeas betAveen the rows is put in. This is fol- 

 lowed by winter oats, which, in turn, are followed by spring 

 cowpeas sown broadcast. The peas are pastured down or cut 

 and followed by sweet potatoes. Such rotations would leave 

 the soil in excellent condition for sweet potatoes. Care should 

 be taken not to plow under heavy crops of rye or clover just 

 before the plants are transplanted to the field. 



Preparation of the soil. — The soil should be carefully prepared 

 before setting the plants. It is a fatal mistake to attempt to 

 make the cultivation of the sweet potato during the growing 

 season take the place of the "tillage of preparation." It is 

 necessary to pulverize the soil thoroughly for the best results. 

 Stucky suggests that this may be done best by breaking the 

 land eight or nine inches deep Avith a two-horse disc i^low and 

 following this mth a disc harrow. 



About a week before planting, the land should be thrown into 

 narrow ridges, about three or four feet apart, liy means of a 

 one-horse plow or "sweep." At planting time these ridges are 

 partly leveled by dragging a small log, or any home-made board 

 scraper, down the rows, leaving a smooth, moist surface for the 

 plants. 



Sweet potatoes demand a soil which carries a moderate 

 amount of organic matter. This may be supplied in sufficient 

 quantity by turning under cover crops, as previously suggested, 

 or by the use of manures and composts. Where stable manure 

 is used it should be applied to the crop preceding the sweet 

 potatoes. Well-rotted composts may be applied at the rate of 

 fifty to seventy-five tons per acre during the winter preceding 

 planting. 



Stable manure, when applied alone to the soil in large 

 quantities, according to Stuckey,* gave a heaw yield of vines 

 and a heaA^^ yield of tubers. The potatoes, however, were rough 

 and poor in quality. 



Commercial fertilizers. — These fertilizers may be used very 

 profitably on sweet potatoes. However, one should be careful 



