of water in soils. Several well-known acids, result- 

 ing from decomposition, unite with soil moisture and 

 dissolve what ordinary water will not. Insoluble 

 forms of fertilizers, such as phosphate of lime and 

 silicate of potash, are probably thus made available 

 to the plant. 



Moist soils swell and are more permeable. Roots 

 can develop faster in them, and the fertilizers, applied 

 to the top six inches, as they gradually dissolve, can 

 be carried more easily and deeply, increasing the 

 feeding area of the roots and the development of the 

 plant. 



IRRIGATION AND FERTILIZERS. 



Plants can take up food, only when it is provided 

 in solution. The food may be dissolved by water, or 

 by direct root action, or by the process of fermenta- 

 tion, which is almost constant in all soils. In either 

 case water is essential, and the common carrier, and 

 the way in which it is used, seriously affects the re- 

 sults of fertilization. Especially is this true because 

 the top foot of soil contains the most valuable 

 fertilizing ingredients. 



There are three kinds of water in soils: free 

 water, which moves by gravity ; hygroscopic water, 

 detectable only by laboratory methods even in the 

 dryest earth, and capillary water, which moves by 

 the power of attraction between particles of matter. 

 This capillary water is what plants feed and depend 



45 



