186 SOILS AND FERTILIZERS 



Sulfate of Potash 



This salt appears as a light yellowish powder, soluble in water and 

 non-deliquescent. 



Dip a crystal in hydrochloric acid and then place in the flame. 

 The violet color is a test for potash. 



Wood Ashes 



Wood ashes are so characteristic as to need but little description. 

 Leach a small portion with water and test the percolate with litmus 

 paper. 



Sulfur 



Sulfur is a yellowish gray powder. It melts readily and burns 

 with a bluish flame, giving a characteristic odor. It is insoluble in 

 water. 



Exercise III. — Comparison of fertilizer effects on plant 

 growth. 



Materials. — Fertilizers, flower pots, poor sandy soil, oat seed. 



Procedure. — The study of the effect of the various potash fer- 

 tilizers as well as of sulfur might be of value. Fill the required 

 number of flower pots with the same quantity of a poor sandy loam 

 after thoroughly mixing the fertilizer with the soil. 



If the effects of the various potash fertilizers are to be compared 

 add them respectively at the rate of 250 pounds per acre (1 of fer- 

 tilizer to 10,000 of soil). Apply at same time sodium nitrate and 

 acid phosphate at the rate of 1 of fertilizer to 5000 of soil respec- 

 tively. Add one gram of lime to each pot. Leave one pot un- 

 treated with potash fertilizers as a check. 



If sulfur is to be used apply it at the rate of 250 pounds per acre. 

 Leave one pot with no treatment, have one to which only sulfur is 

 applied, prepare a third with a complete fertilizer only (mixture 

 of equal parts of sodium nitrate, acid phosphate and sulfate of 

 potash applied at the rate of 1 of fertilizer mixture to 5000 of soil), 

 and a fourth pot with sulfur plus the complete fertilizer. 



Carry out the experiment as explained in Exercise III, Chapter 

 XI, and observe results. 



