324 SOILS AND FERTILIZERS 



water bath kept at a temperature of about 40 C. Stir occasion- 

 ally, and at the end of five hours observe and compare the amounts 

 of insoluble matter remaining in the beakers, note also the color 

 and appearance of the solution in each beaker. See Section 1 70. 



Experiment No. 27 



Preparation of Fertilizers 



Mix in a box 200 gms. acid phosphate (saved from Experiment 

 No. 25), 50 gms. kainit, and 50 gms. sodium nitrate. Calculate the 

 percentage composition of this fertilizer and its trade value. 



Experiment No. 28 



Testing Ashes 



Test samples of leached and unleached ashes in the way de- 

 scribed in Section 256. 



Experiment No. 29 

 Extracting Water Soluble Materials from a Commercial Fertilizer 



Dry and weigh a 7 cm. filter paper. Fit it in a funnel, and place 

 in it 2 gms. of commercial fertilizer. Pass through the filter, a little 

 at a time, a half liter of pure water at about 40 C. (distilled 

 water preferred). Transfer the filter paper and contents to a watch 

 glass, dry in a water oven, weigh and calculate the per cent of 

 material extracted by the water. If the fertilizer is made of such 

 materials as acid phosphate, kainit, muriate or sulphate of potash, 

 nitrate of soda and sulphate of ammonia, from 60 to 90 per cent 

 will dissolve. Inspect the insoluble residue and note if it is 

 composed of dried blood, bones, or animal refuse material. Of a 

 high-grade complete commercial fertilizer from 40 to 80 per cent 

 or more should dissolve in water. 



