352 GARDEN FARMING 



IV. Nitrogen in the form of nitrate of soda containing 16 per 



cent nitrogen . . . . . . . 200 Ib. 



Nitrogen and phosphoric acid in the form of tankage con- 

 taining 8 per cent nitrogen and 1 1 per cent phosphoric 



acid 600 Ib. 



Phosphoric acid in the form of 1 6 per cent acid phosphate 800 Ib. 

 Potash in the form of high-grade sulphate of potash con- 

 taining 50 per cent potash 400 Ib. 



This mixture contains 4 per cent nitrogen, 9.7 per cent available 

 phosphoric acid, and 10 per cent potash. 



In using commercial fertilizers it is the common practice to 

 apply about half with a grain drill, and the other half in the row 

 with the potato planter or some other distributor at the time the 

 seed is covered. The quantity of high-grade fertilizer used depends 

 upon the character of the soil and the preparatory crop ; for the 

 late, or winter, crop of potatoes from 500 to 1200 pounds to the 

 acre are used, while from i ooo to 2000 pounds are frequently used 

 on the spring crop in the trucking region. Where the quantity is 

 as small as 500 pounds, it is not necessary to distribute it broad- 

 cast with a grain drill ; it may be applied with the potato planter 

 at the time the planting is done. Ordinarily it is best to distribute 

 the fertilizer several days in advance of planting the seed in order 

 that any free acid which may exist in the chemicals may become 

 neutralized by the soil or dissipated through it. Large quantities 

 of fertilizers placed immediately in contact with the seeds seem to 

 have a detrimental effect, especially in dry seasons, and as the 

 character of the season cannot be foretold it is advisable to ob- 

 serve the precautionary measures just noted. 



Planting. As has been suggested, potatoes are commonly planted 

 at intervals of from 9 to 1 5 inches in rows about 30 inches apart. 

 Where labor is scarce, however, and it is desired to carry on the 

 entire cultivation of the area by horse power, some growers have 

 satisfied themselves that it is more economical to plant in hills 

 30 inches apart each way so as to admit of cultivation in both di- 

 rections. This of course gives only half as many hills to the acre, 

 but admits of the use of horse-power implements in the field 

 cultivation of the crop. When grown in a small way potatoes are 

 usually planted by hand, but when grown on an extensive scale a 

 planter similar to the type shown in figure 127 is employed for 



