Mr. E. S. Carmen, editor of the Rural New Torker, Food for 



experimented with fertilizers on potatoes on rich land with ^^^1 



the following results : ^^ 



1. 400 pounds superphosphate and 300 pounds sul- 



phate of potash 245 bushels per acre. 



2. Same as plot i with the addition of 200 pounds of 



Nitrate of Soda 348 bushels per acre. 



It is evident from the fact that the addition of 200 



pounds of Nitrate of Soda produced 103 bushels more than 



the superphosphate and potash alone, that potatoes must 



have Nitrogen, and that in greater quantities than is supplied 



by the ordinary so-called "Complete Potato Manure." 



It is the usual practice among sweet c- r. 



^ , 9 . ^ Sweet Potatoes, 



potato growers to use large quantities or 



stable manure for this crop. In 1891 the New Jersey 



Experiment Station made some experiments in order to 



determine whether commercial fertilizers could not be used 



instead of stable manure, which is a large item of expense. 



The experiment was conducted on the farm of Mr. 



Theodore Brown, in Gloucester County, New Jersey. The 



following table gives the most important results: 



Experiment with Fertilizers on Sweet Potatoes. 



I." J c c .T J .-. Cost of Bushels rer acre. 



K.ind or rertilizer and quantity per acre. • ■,• , ^ ,, .-., 



fertilizer. Large. Small. Total. 



1. No manure 157 51 208 



2. 320 lbs. bone-black, 160 lbs. muriate 



of potash $7-70 205 36 241 



3. 200 lbs. Nitrate of Soda, 320 lbs. 



bone-black, 160 lbs. muriate ot" potash 12.34 270 58 328 



4. 20 tons barn-vard manure 30.00 263 61 324 



It will be seen that the addition of Nitrate of Soda to 

 the bone-black and potash gave an increase of 65 bushels 

 per acre, and that the Nitrate, bone-black and potash, 

 together costing ^12.34, produced a little larger yield than 

 20 tons of manure, costing $30.00. In speaking of the 

 results. Professor Voorhees says: 



" Another point of considerable importance, since it has reference to the 

 salability of the potatoes, was noticed at the time of digging, viz. : That 

 those grown with chemical manures alone were bright and smooth of skin, 

 while at least one-third of those grown with barn-vard manure were rough 

 and partially covered with scurf." 



