Nov., 1912.] ANNUAL REPORTS. 19 



(i. When other potassium salts react, with the soil new bases do appear in 

 solution. 



7. Excepting phosphoric, the solubility of the common acid readicals is not 

 affected by the action of the soil. 



8. The effect of such salts as sodium chloride, sodium nitrate, sodium car- 

 bonate and acid phosphate is to greatly increase the solubility of the soil 

 potassium. 



9. The reaction between these salts and the soil is chemical. 



10. Calcium carbonate, calcium sulphate and calcium oxide have practically 

 no effect on the solubility of soil potassium. 



1 1 . The feldspar minerals have a definite solubility in water. This solubility 

 is affected by lime and the common salts found in fertilizers. The effect of 

 these is modified by the presence of clay. 



12. Field observations show that potassium fertilizers do not produce 

 increased yields of grass particularly on clay soils. In some combinations they 

 are more effective on the sandy soils, but not profitably so. 



13. In many cases nitrate of soda alone produces yields as good as are 

 obtained with a combination of nitrate of soda and potassium salts. This 

 may be due to the effect of the nitrate of soda on the soil potassium. 



14. The composition of the hay shows that when no potassium fertilizers 

 are used the soil affords plenty of potassium for the growth of the crop. This 

 is true for large yields. 



15. From a practical point of view little profit can be expected from the 

 use of potassium fertilizers for the production of hay. 



These statements are taken from Volume 15, page 70, original communica- 

 tions, Eighth International Congress of Applied Chemistry, and constitute a 

 summary of the results reported there. The facts discussed in this paper have 

 a very practical bearing on the economical production of grass. 



The department has also published a technical paper on a short method 

 for the determination of soluble arsenic in commercial lead arsenate. Journal 

 of Industrial and Engineering Chemistry, Vol. 4, 1912. A method is given 

 whereby the time necessary for the determination may be shortened very 

 materially over that required by other methods. 



The cooperative work on grass production shows the universal need of more 

 nitrogen. Nitrogen is found to be one of the chief limiting factors in the pro- 

 duction of large yields. The need of more cultivation and better methods of 

 fertilization has been found. 



Under the Adams Act no new work has been undertaken. The facilities 

 and personnel have undergone no change since the last report. The present 

 status of this work is represented by the report above cited. No general 

 conclusions can yet be di*awn from the lime work. 



The department is required to do a larger amount of miscellaneous work from 

 year to year. During the past year the total numbers of fertilizers and feeding 

 stuffs have practically doubled in number. 



