192 SOILS AND FERTILIZERS 



238. Action of Ashes on Soils. — In ashes, the pot- 

 ash is present mainly as potassium carbonate. Ashes 

 are usually regarded as a potash fertilizer only, but 

 they also contain lime and phosphoric acid, and may 

 be very beneficial in supplying these elements. They 

 are valuable too because they add alkaline matter to 

 the soil, which corrects acidity and aids nitrification. 

 A dressing of ashes improves the mechanical condi- 

 tion of many soils by binding together the soil parti- 

 cles. This property is well illustrated in the so-called 

 "Gumbo" soils, which contain so much alkaline mat- 

 ter that the soil has a soapy taste and feel, and when 

 plowed the particles fail to separate. 



239. Leached Ashes. — When ashes are leached the 

 soluble salts are extracted, and the insoluble matter 

 which is left is composed mainly of calcium carbonate 

 and silica. 65 



Uuleached ashes. Leached ashes. 



Per cent. Per cent. 



Water 12.0 30.0 



Silica, etc 13.0 13.0 



Potassium carbonate 5.5 1. 1 



Calcium " 61.0 51.0 



Phosphoric acid 1.9 1.4 



240. Alkalinity of Leached and Unleached Ashes. 

 — A good way to detect leached ashes is to deter- 

 mine the alkalinity in the following way : Weigh 

 out 2 grams of ashes into a beaker, add 100 cc. dis- 

 tilled water, and heat on a sand-bath nearly to boiling, 



