GRANITIC SOIL POTASSIUM AND ITS RELATION TO 

 THE PRODUCTION OF HAY* 



By B. E. Curry and T. O. Smith 



Until recent years, the theory of soil fertilization has rested al- 

 most entirely upon the practice of adding plant food or amend- 

 ments to the soil in the form of fertilizers and manures for the 

 purpose of increasing production. In practice, the ultimate aim 

 is to obtain an increased production at a profit. With our present 

 knowledge of soil management, tillage, and fertilization, it is a 

 simple proposition to increase yields, but it is not as simple a 

 proposition to secure profitable increased yields. It is doubtful, 

 from a practical point of view, whether the maximum yield is the 

 most profitable. 



The practice of applying fertilizers is followed because the 

 amount of plant food in the soil is considered insufficient or un- 

 available for the needs of the crop. For special cases, as in mar- 

 ket gardening and greenhouse culture, where high-priced crops 

 are grown, the relatively small cost of fertilizers becomes almost 

 negligible. In other crops, such as the average farmer grows, 

 the difference of a few dollars makes the difference between 

 profit and loss. The aggregate of values of farm crops is largely 

 derived from the ordinary' crops grown under ordinary con- 

 ditions. 



In New Hampshire, one of the large cash crops is hay. The 

 farms have generally been allowed to run down and become un- 

 productive. The soil is apparently as good as it ever was, but 

 through neglect, production has decreased. A larger acreage 

 is devoted to grass than to any other crop. This condition has 

 become established through the natural adaptability of the soil 

 to grass culture, and through certain economic factors due to 

 location and labor problems. The heavy horse and ox power 

 once so common on New Hampshire farms is now largely a con- 

 dition of the past. Parth' because of this, the land does not get 

 the cultivation it once had. Commercial fertilizers have in part 



* A continuation of the work reported at the Eighth International Con- 

 gress of Applied Chemistry, Vol. XV, page 51. 



