UNIVERSITY OF CALIFORNIA. 



indispensable soil ingredients, their distribution, func- 

 tions and sources of supply. 

 Distribution of Ash ingredients in Horse Chestnut, Beet, Cereals, 



etc. 



Amount and character of ashes in old and young leaves, 

 stems, wood, etc. 



Metallic Elements. 



* 



Potash. Percentage contained in soils. Examples. How 

 contained. Feldspar Zeolitic compounds. Mechan- 

 ical absorption. Liebig's experiments. 

 Laws of surface absorption. Composition of drain waters. 

 Root crops especially exhaustive of Potash. 

 Potash manures in general. 

 Soda. Inferior in importance to Potash. 



, Small amount in soils easily washed out, yet rarely needs 



to be supplied. 

 Salty soils Salt plants. 

 Sodium salts used in agriculture. 

 Oflwr Alkalies in minimum quantities. 



Lime. Amount usually present in soils. Relation to Po- 

 tash. Nutritive as well as stimulant. 

 Largely present in stems. 

 General importance as a soil ingredient, both physical 



and chemical. 



Effects on mechanical condition of Soil. 

 "Flocculation." 



Renders soils loose, pervious, tillable "warms" them. 

 Chemical Effects of Lime "fallowing" action. 



Effects on organic decay, and formation of "humus." 

 How present carbonate, sulphate, phosphate, humate. 

 Natural characteristics of calcareous soils their growth, 



color, thriftiness. Examples. 

 Importance of a supply of lime to Agriculture. 

 Magnesia. Like lime, important stem ingredient. 



Rarely deficient in soils seldom needs to be supplied. 



Partially replaces lime. 

 Percentage in Soils. Numerical relation to potash. How 



present in soils. 

 Copiously carried off in drain waters. Soluble magnesium 



salts injurious to vegetation. 



Alumina. Not a true ash ingredient, though often found in 

 ashes. 99 



