252 FERTILIZERS. 



family ; they are not, however, of the same necessity as potash and soda, or lime. We are 

 looking now to the value of different materials for the growth and production of vegetables. 



Carbonate of Potash. In no case can the uncombLned potash be employed in husbandry, or 



as a food for plants. Indeed such is its avidity for carbonic acid and wat t it almost 



baffles the skill of chemists to preserve potash pure, or prevent its combination with these sub- 

 stances. Wood ashes, as is well known, contain the carbonate of potash ; and r . i them 

 it is obtained by lixiviation. By reference to the analysis of the ashes of diffcini. sp^^cies of 

 wood, it will not escape the attention of the reader that different species contain potash in dif- 

 ferent proportions ; so also another fact of equal importance will appear, that different parts of 

 the same tree contain this alkali in different proportions. 



As a fertilizer, the facts in regard to its value will correspond with the foregoing statements, 

 some plants requiring more and some less. It is, however, a necessary constituent of every 

 soil 5 and where it is wanting, a soil is utterly barren — so far as it is capable of producing 

 valuable plants, for the use of man and animals. The impure carbonate of potash, as it exists 

 in ashes, is the form in which it is usually applied to soils. Farmers, however, have been 

 too much in the habit of selling their ashes at a price far less than they are worth for agricul- 

 tural purposes. In selling ashes, however, it is not disposing of potash alone, but also of the 

 phosphoiic acid, in which they more or less abound ; and even where they are not sold, it is 

 not uncommon to leave them in heaps, in their yards, especially their leached ones, which are 

 still highly valuable, from the phosphates of lime, magnesia and silicate of potash, which they 

 still retain. 



The value of ashes has been proved by long use. When obtained from the soap boiler, or 

 from an ashery, they are usually spread upon the land with a shovel, and not sown. The 

 quantity has varied with different individuals : from fifty to seventy bushels per acre have been 

 given to the laud. In this proportion the crops exhibit its presence for ten or twelve years. 

 Gravelly and sandy soils are especially benefited by this application, for not only are valuable 

 substances added, but the mechanical condition of the soil is improved also. Ashes, in the form 

 and quantity stated above, will increase the compactness of a gravelly or sandy soil, and do 

 something for obviating the looseness of such lands and prevent the rapid loss of the fertilizers. 



Another profitable mode of applying ashes is to sprinkle a spoonful or two upon the hills of 

 maize or potatoes, after they have attained a height of two or three inches. The good effect 

 seems to be increased by making this application just before a rain. Leached ashes have a 

 tendency to form a compact bed. When laid upon a cellar bottom they form a perfectly hard, 

 dry surface ; and when spread upon the walks of a garden, it becomes so compact and hard 

 that weeds rarely grow upon the surface. These facts illustrate the effects which would fol- 

 low from an excessive use of ashes, leached or unleached. 



Coal ashes possess an inferior value : it is, no doubt, variable. They contain, besides matters 

 insoluble in acids, lime, magnesia, iron, manganese and traces of potash, and phosphoric acid. 

 Good effects appear to follow from their use upon grass lands, and are partially valuable on 

 stiff clay lands. Very few farmers, however, have thought it profitable to trouble themselves 



