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No. 4.] POTATO GROWING. 361 



spring the land should be thoroughly worked. The best possible 

 seed bed should be prepared, so that the soil will be light and thoroughly 

 pulverized to a depth of 5 or even 6 inches. In a soil thus prepared 

 the planter will run easily. 



The Potato needs Abundant Plant Food. 

 It is always profitable to fertilize a money crop liberally, and, 

 while a crop of 300 bushels of potatoes will remove from the soil 

 about 55 pounds of nitrogen, 25 pounds of phosphoric acid and 85 

 pounds of potash, it is probably wise to furnish the phosphoric acid 

 in considerable excess and the potash in fair excess. The plowed- 

 under clover and the fertility which has been accumulated can be 

 depended upon for part of the nitrogen. By many experiments it 

 has been found that the potato plant thrives best in a soil abun- 

 dantly supplied with all fertilizing elements. In the early stages of 

 growth nitrogen is particularly demanded, and hence a considerable 

 part of the nitrogen should be in a readily available water-soluble 

 form. This is necessary that it may be utilized by the plants early 

 in the season. Later when the tubers are forming, there is special 

 demand for phosphoric acid and potash. 



Selection of the Fertilizer. 



In the selection of a fertilizer, a farmer cannot be guided by the name 

 alone. There are all kinds of "potato" fertilizers upon the market, — 

 those carrying from 1 to 5 per cent nitrogen, from 5 to 10 per cent 

 phosphoric acid and from 2 to 12 per cent potash. In selecting the 

 fertilizer, something more than percentage composition must be 

 taken into account. 



At the present time a 4-G-lO fertilizer, carrying 4 per cent of 

 ammonia, which is equivalent to 3.3 per cent nitrogen, 6 per cent 

 available phosphoric acid and 10 per cent potash is a popular potato 

 fertilizer in Maine. Used at the rate of 1,500 pounds to the acre, 

 such a fertilizer would supply about 50 pounds of nitrogen, 90 pounds 

 available phosphoric acid and 150 pounds of potash. Obviously 

 such a fertilizer when compared with the needs of the crop is out of 

 balance. As the results of field experiments with potatoes, it is prob- 

 able that the excess of phosphoric acid is valuable to the crop. There 

 is no evidence, however, to show that the potato crop is benefited 

 by such a great excess of potash. It would seem that if 1,500 pounds 

 of a high-grade fertilizer is to be used, one carrying 6 or 7 per cent 

 of potash in place of the 10 would be better balanced. 



The Form of Fertilizing Ingredients. 

 In 1907 a high-grade potato fertilizer was used in large quantities, 

 in Maine, on potatoes, which did not carry any nitrate nitrogen. 

 There was quite a general complaint as regards failure with this 



