MIXTURES FOR CROPS 



supplied freely, and phosphoric acid and potash 

 must likewise be given the soil. The draft upon 

 the soil is heavy, and at the same time the effort 

 should be to have a sod to be broken for corn that 

 will produce a big crop without the use of any 

 fertilizer. The grass is the natural crop to re- 

 ceive'the plant-food because its roots fill the ground, 

 and the corn should get its food from the rotting 

 sod, when broken. Station tests have shown 

 that a sod can be caused to increase in productive- 

 ness for several years by means of annual applica- 

 tions of the right combinations of plant-food in the 

 early spring. A mixture of 150 pounds of nitrate 

 of soda, 150 pounds of acid phosphate, and 50 

 pounds of muriate of potash is excellent. This 

 gives nearly the same quantity each of nitrogen, 

 phosphoric acid, and potash, and is near a 7-7-7 

 fertilizer. The only material change in relative 

 amounts of plant-food constituents, when com- 

 pared with a 3-10-6 and 3-8-10 fertilizer, is in the 

 increase of nitrogen, due to the heavy drafts made 

 by continuous mowings of timothy. This fer- 

 tilizer should be used as soon as any green appears 

 in the grass field in the spring after the year of 

 clover harvest. The large amount of nitrogen 

 makes this an unprofitable fertilizer for clover, and 



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