MANURES AND FERTILIZERS. 65 



produced an increase of crop in 46 out of 48 

 trials; and (2) in no case has the increase in 

 crop been sufficient to pay cost of fertilizer." * 

 This work is supplemented by further work 

 along the same line.f Twenty-one separate 

 experiments were made on soils varying widely 

 in character and located in different parts of 

 the State, and extending over at least six years. 

 As a result of this work Director Thorne con- 

 cludes: 



"At present prices of cereal props and of fertilizing ma- 

 terials, respectively, the profitable production of corn, wheat 

 and oats upon chemical or commercial fertilizers, or upon 

 barn-yard manure, if its cost be proportionate to that of the 

 chemical constituents of fertility found in commercial fer- 

 tilizers, is a hopeless undertaking, unless these crops be 

 grown in a systematic rotation with clover or a similar 

 nitrogen-storing crop; and the poorer the soil in natural fer- 

 tility the smaller the probability of profitable crop produc- 

 tion by means of artificial fertilizers." 



At the Kentucky station, on land rich in 

 phosphoric acid, a mixture of muriate of potash ■ 

 and nitrate of soda in the proportion of one 

 part of the former to two of the la,tter gave the 

 best yields of grain, viz.: an increase of 39 

 bushels per acre over where no fertilizer was, 

 applied. Combinations of nitrogen and phos- 

 phoric acid, or single applications of either, 

 gave practically a less yield than where no 



* Ohio agricultural experiment station. Bulletin 3, Vol. V, 

 March, 1892. 



t Ibid., Bulletin 53, March 1894. 

 5 



