112 The Sweet Potato 



soil hastens the maturity of the crop and increases the 

 yield. On poor soil, lime and potash work together to 

 produce uniform sizes and shape. Lime, for the best 

 results, should be applied the year previous to planting 

 sweet potatoes. 



Application of fertilizers. (Plate III.) 



Since the sweet potato plant .when transplanted in the 

 field is ready to begin growth, all fertilizers are best 

 applied sometime before the plants are set. The com- 

 mon practice is to apply commercial fertilizers in the 

 drill at the time of making the rows. This is ordinarily 

 done by distributing the fertilizer in the middles be- 

 tween rows, mixing it with the soil by stirring with a 

 scooter or bull-tongue, and then bedding on top of it by 

 throwing two furrows together with a turn plow. It 

 is very important that kainit (when used as source of 

 potash) be thoroughly mixed with the soil before plant- 

 ing, as cases have been reported in which this fertilizer 

 injured the crop. 



EOTATIOlir 



The growing of a series of crops on the same land in 

 definite order throughout a period of years constitutes 

 what is termed crop rotation. 



Proper rotation is now recognized to' be a necessity to 

 maximum production and efficiency with all crops. In 

 fact, it is quite as important to the permanent welfare 

 of the soil as to the yield and quality of the plants 

 grown, and the kind of rotation practiced will have 

 fully as much influence on both as does cultivation or 

 fertilization. 



A seed-bed may be perfectly prepared; plant-food 



