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THE HOME, FARM AND BUSINESS CYCLOPEDIA. 



TABLE SHOWING THE COMPOSITION OF A FERTILE ALLUVIAL SOIL from near 

 the Zuider Zee, in Holland, analysed by Baumhauer. 



The proportion of plant food present in soils is very small, even when 

 the soil is extremely fertile. The surface soil (first 9 inches) of a pasture 

 may contain when dry 0'25 of nitrogen per cent., while soil of the same 

 depth from a good arable field may yield 0*15 per cent., and a clay sub- 

 soil O'Oo per cent. A good surface soil may contain 0'20 per cent, of 

 phosphate acid, or not unfrequently a smaller quantity. Potash varies 

 much, rising to TO per cent., or more in some clay soils, but being gene- 

 rally much smaller. 



The weight of soil on an acre of land is, however, so enormous, that 

 small proportions of plant food may amount to very considerable quanti- 

 ties. Nine inches' depth of arable soil (clay or loam) will weigh, when 

 perfectly dry, about 3,000,000 or 3,500,000 Ibs. A pasture soil will be 

 lighter, the first nine inches weighing when dried and the roots removed 

 about 2,250,000 Ibs. Supposing, therefore, a dry soil to contain O'lO per 

 cent, of nitrogen, phosphoric acid, or potash, the quantity in nine inches 

 of soil will be from 2250 Ibs. to 3500 Ibs. per acre. 



A large part of the elements of plant food contained in soils is present 

 in such a condition that plants are unable to make use of it. A soil may 

 contain many thousand pounds of phosphoric acid or of nitrogen, and yet 



