FERTILIZERS 27 



acidulation, and results in greater fertility. A num- 

 ber of lay experiments and actual practice in, Calk. 

 fornia agree with the results of the Pennsylvania 

 State Experiment Station. Where there was little on 

 no humus-forming material in the soil, 



forms gave the best results. Dr. Hopkins of the 

 Illinois State Experiment Station and many others 

 strongly advocate the use of finely ground, unacidu- 

 lated phosphates with plenty of humus material, 

 rather than the acidulated forms. (7),(8),(11). 



SOURCES OF POTASH. 



41. Potash is found as a chloride, or muriate, as 

 a sulphate, and in a crude form called kainit. The 

 latter contains 12 J /i% actual potash. The muriate 

 and sulphate analyze about 50% actual potash. 

 The Strassfurt mines in Germany supply the most of 

 this product. 



The potash of manufactured fertilizers is never 

 all animal matter. All commercial forms dissolve 

 readily, so there is no danger of buying potash in 

 unavailable form. It takes about two pounds of sul- 

 phate, or muriate of potash to make one pound 

 actual potash, or 10% sulphate to make 5% "actual." 



Wood ashes arid stable manure are also sources of 

 potash, obtainable, however, in very limited quan- 

 tities. Wood ashes, unleached, will contain from 

 4%% to 7% potash: mixed stable manure contains 

 about 0.4% potash. 



The sulphate of potash is the best form in which 

 to purchase. It has no ill effects on many plants, 



