POTASH AND SULFUR FERTILIZERS 185 



Whether, under ordinary methods of farming, it is desir- 

 able to use any fertilizer for the sulfur it contains has not yet 

 been ascertained. It would appear, however, to be a subject 

 worthy of consideration. 



QUESTIONS 



1. What occurs to a soluble potash fertilizer when applied to 

 soil? 



2. With thousands of pounds of potash in an acre of soil, why 

 do a few pounds of fertilizer increase the supply available to plants ? 



3. Where are most of the potash fertilizers obtained? 



4. Name the potash fertilizers. 



5. Describe the effects of potash on plant growth. 



6. Name some crops that are particularly benefited by potash. 



7. Is there any indication that the use of sulfur as a fertilizer 

 may be desirable ? 



8. In what manures and fertilizers is sulfur contained ? 



LABORATORY EXERCISES 



Exercise I. — In Exercise V, Chapter I, an experiment designed 

 to show the importance of three plant-food materials to plant 

 growth was described. If this test has been properly carried out it 

 should now be available to show the effects of potash on plant de- 

 velopment. 



Exercise II. — Examination and identification of potash fer- 

 tilizers and sulfur. 



Materials. — Set of fertilizers (consisting of muriate of potash, 

 sulfate of potash, wood ashes and sulfur), nitric acid, hydrochloric 

 acid, silver nitrate, filter paper and funnel, flame, litmus paper. 



Procedure. — The fertilizers should be studied and tested until 

 identification is sure. 



Muriate of Potash 



This salt is placed on the market as opaque crystals, soluble in 

 water. 



Dissolve a small portion of the fertilizer in water and filter. 

 Add a drop of nitric acid and then silver nitrate. A white curdy 

 precipitate indicates the presence of muriate. 



