ANALYSIS OF SOILS. 



27 



sulphuric acid and silica. If, however, we come to the substance that we call potash, we 

 shall find, as a rule, that plants take a large quantity of it, a large proportional quantity, 

 and that potash is very deficient in the soil. The constant cropping has exhausted the soil of 

 potash, and the farmer must supply it. All scientists agree on this matter, that so far as 

 the farmer is concerned in supplying the wants of the plant, the only substances that he need 

 supply will be potash, phosphoric acid, and nitrogen. My own experiments seem to show 

 that with one or two plants, he should give them a little of something else, which are mag 

 nesia, and a little lime for the tobacco and cotton plant.&quot; 



We see, therefore, that if the above principle is correct, it will be a very easy matter 

 for the farmer to test his soil, and find in what it is deficient. It may be deficient in one or 

 all of these elements, but by careful experiment and noting the effect upon different plots of 

 ground, of each of the above mentioned fertilizers, applied separately and in combination, he 

 can soon determine by the results, which of these elements are requisite to the improvement 

 of his lands. 



These elements can be obtained in commercial fertilizers, or they can be prepared by the 

 farmer himself, who can obtain a good supply of potash in the form of wood ashes; of nitro 

 gen, in the form of fish-guano, and phosphoric acid from a quantity of bones. By careful 

 experiment, any intelligent farmer can thus learn the elements of his soil, and supply the 

 elements of plant-food requisite. 



Since soils differ so greatly that those taken from no two localities, or even from differ, 

 ent portions of the same field, will be found, on analysis, to contain the same proportion of 

 ingredients, still, a fair estimate of the predominant constituents of different kinds of soil 

 can thus be obtained. 



The following are very fertile and arable soils, of which Professor Johnston, an eminent 

 English authority, says: 



&quot;The first had been cropped for 160 years successively, without either manure or naked 

 fallow. The second was a virgin soil, celebrated for its fertility. The third had been unma- 

 nured for twelve years, during the last nine of which it had been cropped with beans, barley, 

 potatoes, winter barley and red clover, clover, winter barley, wheat, oats, naked fallow.&quot; 



Silica and fine Sand, 



Alumina, . 



Oxides of Iron, 



Oxide of Manganese, 



Lime, 



Magnesia, . 



Potash, chiefly combined with Silica, 



Soda, ditto, 



Phosphoric Acid combined with Lime and Oxide 



of Iron, 



Sulphuric Acid in Gypsum, 

 Chlorine in common Salt, 

 Carbonic Acid united to the Lime, 

 Humic Acid, 

 Insoluble Humis, 

 Organic substances containing Nitrogen 



100. 100. 100. 100. 



The following analyses were made by Prof. Collier, chemist for the department of agri 

 culture, at Washington, D. C. : 



No. 1. Green sand marl, from Meridian, Miss. 



No. 2. Clay from Maryland. 



No. 3. Clay from Potomac, Terra Gotta Company. 



