Field Truck Crops 247 



Station also show that organic nitrogen (cotton-seed meal) 

 is preferable to nitrate of soda as a source of nitrogen. 



In making mixtures which furnish these proportions of 

 plant-food, other nitrogenous organic materials furnishing 

 an equivalent of nitrogen as blood or concentrated 

 tankage may be substituted for the cotton-seed meal, 

 if they can be purchased quite as cheaply ; and muriate 

 of potash, furnishing an equivalent of potash, may be sub- 

 stituted for the kainit, if it can be more readily obtained. 



As already stated, however, this fertilizer is too rich in 

 nitrogen for the production of the best quality of potatoes, 

 as, for example, "Vineland Sweets/' which command the 

 highest prices in northern markets. The growers in 

 that district use a fertilizer richer in the minerals; one 

 containing 



Nitrogen 3% 



Phosphoric acid 7% 



Potash 12% 



is very generally used, though reasonably heavy dressings 

 of this are often further supplemented by applications of 

 from 200 to 300 pounds of acid phosphate and 100 to 150 

 pounds of muriate of potash to the acre. 



The application of the fertilizers. 



Owing to the fact that the sweet potato is grown from 

 plants or slips, rather than from seed, and the fact that the 

 best quality of potatoes is produced upon rather light, 

 sandy land, it is desirable that the fertilizer should be 

 applied some time before the putting out of the plants. 

 The practice on this light land is to apply the fertilizer 

 when making up the hills, which usually occurs from two to 

 three weeks before the plants are set. That is, in making 



