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THE IRRIGATION AGE. 



HON. JOHN E. FROST. TOPEKA. KANSAS. 



carbonic acid, ammonia, and nitric acid are the most 

 important. These compounds we shall take up in their 

 order, a knowledge of all of them being of essential 

 importance in agriculture. 



WATER. 



The following are the three qualities of water im- 

 portant to plant life : 



First A solvent power. 



Second An affinity for certain solid substances. 



Third An affinity for its own elements. 



First Water possesses the power of absorbing the 

 several gases of which the atmosphere is composed, and 

 carries them to the roots of plants whence they are 

 taken into the circulation. 



It dissolves many solid inorganic substances, earthy 

 and saline, and conveys them in a fluid form to the 

 roots of plants, which enables them to ascend with the 

 sap. It also takes up substances of organic origin, 

 such as portions of decayed animal and vegetable mat- 

 ter, and likewise brings them within reach of the roots. 



When warm the solvent powers of water over solid 

 substances is very much increased, a fact which ac- 

 counts for the luxuriant vegetation in the tropical and 

 semi-tropical regions, and in what are known as "warm 

 soils." 



Second Water exhibits a remarkable affinity for 

 solid substances. A familiar instance is mixing water 

 with quick lime. The lime heats, cracks, swells, and 

 finally becomes a white powder. This is familiarly 

 known as "slaking" lime. When thoroughly slaked, the 

 lime will be found to be one-third heavier than before. 

 Every three tons of lime, therefore, absorb one ton 

 of water; hence, if four tons of slaked lime is put 

 upon land one ton of water is also mixed in the soil. 



Water has an affinity for clay, the hottest sum- 

 mer seldom robbing the clay of its water, enough be- 

 ing retained to keep wheat green and flourishing when 

 plants on lighter soils are drooping and burning up. 



An affinity for water causes vegetable matter to 

 combine chemically with it, but in the case of a porous 

 soil the water is merely "drunk in" mechanically and 

 it is retained unchanged in the pores of the soil, whence 

 it may be evaporated out, as related in the last chapter, 

 but not where there has been a chemical transforma- 

 tion. This is a fact that should be remembered in 

 applying mixtures of vegetable matter to the soil by 

 way of fertilization. A mere mechanical mixture is of 

 little effect; there must be a chemical transformation 

 provided for. And it should also not be forgotten that 

 water itself is capable of a chemical change whereby its 

 qualities are preserved and retained much longer, in- 

 deed, than if merely poured upon the soil as a mechan- 

 ical attempt to assist plant growth. 



Third Water possesses an affinity for its own ele- 

 ments, and this fact exercises a material influence on 

 the growth and production of all vegetable substances. 

 In the interior of plants, as in animals, water undergoes 



GEO. L. McDONAUGH. 

 COLON1XATION AGENT, UNION PACIFIC RAILWAY. 



1*ROF. CHAS. W. HALL 

 FARGO, N. D. 



