336 



Bulletin 241. 



nearest adjacent yielded at the rate of 2410 pounds of hay per acre. 

 Six plats, which received a complete commercial fertilizer in vary- 

 ing amounts and proportions, yielded in 1906 at the rate of 7057 

 pounds per acre, while four unfertilized plats nearest adjacent, 

 yielded at the rate of 3192 pounds or approximately three and 

 one-half and one and one-half tons respectively. The average cost 

 of the fertilizer, which on some plats was put on in excessive and 

 not economical amounts, was at the price given in Bulletin 232, 

 $10.93 P^*" acre. 

 The relative influence of the dififerent fertilizers can best be seen by 

 studying in detail the apparent increases in yield due to fertilizers 



as shown on pages . The following table gives the 



results in condensed form: 



No. of 

 Plats. 



Nitrogen 



Phosphorus 



Potassium 



Nitrogen and Phosphorus 



Nitrogen and Potassium 



Phosphorus and Potassium. 



Nitrogen, Phosphorus and Potassium 

 Manure, 10 and 20 tons 



This table shows clearly that fertilizers containing nitrogen pro- 

 duced the greatest increase in yield of hay, that fertilizers con- 

 taining potassium stood next, while fertilizers containing phos- 

 phorus in the form of acid phosphate produced the least increase 

 in yield. At least a part of the increase in yield on the plats 

 receiving potassium was due to the increase in alsike clover. While 

 only timothy was supposed to be sown, on the plats receiving 

 potassium alone or potassium and phosphorus alone, alsike clover 

 assumed an important part of the total crop, while elsewhere the 

 hay would pass for pure timothy. A critical examination of the 

 plats, however, showed a few plants of alsike clover. On plats 

 receiving potassium alone, or potassium and phosphorus only, 

 these plants grew to large size, but on the other plats they were so 

 small as to escape the notice of the casual observer. The stand of 

 alsike clover seemed greater also, but this may have been due to 

 the larger size of the individual plants. 



