THE POTATO 



315 



the needed nitrogen, and the decay of the vegetable matter may free all of 

 the potash required, but we now have relatively small areas in which 

 phosphorus does not add materially to crop yields. As potato production 

 continues, a need of nitrogen develops, and as has been said, potash is a 

 requirement for most sandy soils. A lack of fertility may be met by use of 

 a fertilizer containing 3 per cent of nitrogen, 10 per cent of phosphoric acid 

 and 5 or 6 per cent potash excepting, naturally, areas where the percentage 

 of nitrogen must be increased. The amount of fertilizer used per acre 

 varies greatly. Some growers in the seaboard states apply one ton of a 

 high-grade complete fertilizer per acre, and many growers on naturally 



A Potato Planter. 1 



fertile soil in the Central states use none at all. It is a common practice 

 to apply all of the fertilizer in the row, and when the amount is in excess 

 of 1000 pounds per acre, there is danger of injury to the plants as they start 

 growth 



Lime is not applied to land immediately before potatoes are planted, 

 as it favors the development of potato scab. Acid soils are more free from 

 this disease than alkaline ones, but clover demands lime and is needed in a 

 rotation with potatoes. The best practice is to use finely pulverized 

 limestone rather than burned lime and to make the application immediately 

 after the potato crop in the rotation. 



The Planting. — As the potato thrives best in cold latitudes the planting 

 should be made as early as possible in the spring in the Southern states and 



1 From Farmers' Bulletin 365, U. S. Dept. of Agriculture. 



