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results when the same amount and kind of fertilizer applied broadcast 

 is unprofitable, and the same remark applies to light applications on maize. 

 One of the principal reasons for unprofitable results from plot tests 

 is found in failure to make a distinction between the fertilization of crops 

 producing high money values per acre, like truck and fruit, where the 

 whole plant food supply may be profitably secured from chemical manures, 

 and such crops as wheat, oats and maize, where the chemical fertilizers 

 must be used to supplement and balance the supplies from the soil, farm 

 yard and legume held. The cost of full rations of commercial nitrogen 

 can only occasionally be recovered in the wheat crop and rarely if ever 

 in the case of oats and maize. Double ratious of phosphoric acid are often 

 profitable and from one-half to full rations of potash. In most of the 

 early plot experiments full rations were used, and sometimes the cost of 

 the fertilizer for maize was greater than the total sum received for the 

 crop even when the yields were good. 



Perhaps the contrast between the plot tests and the farm practice 

 can be shown better in the form of the amounts per acre and the formula. 

 In some of the wheat plot tests extending over twenty years the fertilizer 

 is the equivalent of 500 pounds per acre of goods having formula of nitro- 

 gen 10 per cent., phosphoric acid 5 per cent, and potash G per cent. ; at the 

 same time this series was started the common wheat fertilizer was 100 to 

 200 pounds per acre of 2-8-2, which has gradually changed to 2-8-6 ; nitro- 

 gen is sometimes increased to 3 per cent. The maize series of plots re- 

 ceived the equivalent of 1.000 pounds per acre of a goods having a formula 

 of nitrogen 12 per cent., phosphoric acid 4 per cent, and potash 6 per cent., 

 while farm practice on maize uses 100 to 300 pounds per acre of goods 

 having little or no nitrogen and containing from 5 to 10 per cent, phos- 

 phoric acid and 4 to 10 per cent, of potash. For clay soils a common 

 maize fertilizer is 0-10-4. for loams 0-8-8 and for black sandy soils 0-6-10, 

 while on the peat or muck soils 100 pounds per acre of muriate of potash 

 or its equivalent in kainit are commonly used. A small amount of nitro- 

 gen is sometimes added, usually about 1 per cent. — rarely over 2. 



The cost per acre of the maize fertilization would be about $30 for 

 the plot work and from $1 to $4 per acre for the fertilizers commonly used. 

 The cost per acre of the wheat fertilization would be about $15 for the 

 plot work and from $1 to $3 per acre for the fertilizers commonly used. 



In general it may be said that the fertilizers used on wheat and maize 

 furnish about as much phosphoric acid as the crop removes, rarely as 



