YIELD OF BARLEY 



33^ 



Yield of Grain per Acre in Bushels — Average Sixteen Years. 



Unmanured .... 



Barnyard manure 



Nitrogen 



Phosphorus 1 .... 

 Potassium ..... 

 Nitrogen and phosphorus . 

 Phosphorus and potassium 

 Nitrogen, phosphorus and potassium 



Salt 



Gypsum 



Oats 



Salt and gypsum both appear to have increased the yield of 

 barley, but to have had less influence on the oats and wheat. 

 Barley appears more dependent on the manurial supplies within 

 the surface soil, probably on account of its shorter period of 

 growth and more limited range of roots. For the same reason, 

 soluble fertilizers, where needed, appear the most effective. 



Phosphorus applied in untreated phosphates. 



