66 STATE HORTICULTUEAL SOCIETY. 



Chemical analysis may determine that all the necessary elements 

 are present in a given soil, and yet its cultivation may yield very unsat- 

 isfactory results. Why? Because one or more of these elements may 

 be in such a form as to make assimilation difttcult or impossible. 



In making a chemical analysis of a soil or fertilizer, solubility in 

 cold water and susceptibility to the influence of oxygen are the princi- 

 pal points for determination. To show the necessity of such a determi- 

 nation, take an example : The leaves of the fruit-trees in a given 

 orchard are small and the wood growth is slow. A careful diagnosis 

 of the case may determine a deficiency of carbon in the soil, and, con- 

 sequently, in the surrounding atmosphere. i?ow, charcoal is almost 

 pure carbon ; yet no one would think of using charcoal as a fertilizer. 

 Why ? Because charcoal is insoluble in water and will not yield to the 

 influence of oxygen. In other words, oxygen will not convert it into 

 a soluble form. But carbonate of lime in the form of common porous 

 limestone, or hydrate of lime in the form of slaked lime, when it makes 

 its combinations in nature's laboratory, will, by gradual decomposition, 

 throw off a sufficiency of carbon in the form of carbonic acid gas to 

 afford proper food for the leaves of fruit-trees. When we remember 

 that such a large per centum of tree-fiber is carbon, and that carbon is 

 not a«isimilated in plant growth only when it is in the form of gas, and, 

 farther, that gas comes from decomposition which is brought about by 

 water, mainly through the oxygen it contains, the importance of water 

 in contact with carbon in a soluble form will appear. 



The great solvent in nature is water. The oxygen in water attacks 

 and decomposes most organic and many inorganic substances, and 

 converts them into oxides and other forms that are highly soluble. In 

 these torms, if required by growing plants, they are easily assimilated. 



This line of illustration is intended to demonstrate that the physi- 

 cal conditions of a given soil are of as much importance in determining 

 its adaptability to a given fruit or other crop product as are its chemi- 

 cal conditions. This leads us into the domain of geology, although 

 chemistry and physics must continue to bear us company. 



These three branches are so correlated that it is not necessary to 

 separate them in this discussion. 



The one great desideratum in soils is porosity. When water and 

 air can percolate and penetrate to great depths, the other conditions 

 being favorable, fruit-trees will flourish. If a soil is porous, water will 

 more surely and rapidly oxidize and decompose its elempnts of fertility. 

 Then these elements are in proper form for plant foods. 



Besides gradually decomposing the fertile elements in a porous 

 soil, water will carry down, to a great depth, much organic matter in 



