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SOILS AND MANUKES 



PERCENTAGE OF PHOSPHORIC ACID AND POTASH EXTRACTED BY STRONG 

 HYDROCHLORIC ACID AND BY A 1 PER CENT. SOLUTION OF CITRIC 

 ACID FROM THE SOIL OF KOTHAMSTED PLOTS. 



SAME IN POUNDS PER ACRE. 



SAME, SHOWING THE KATIO OF THE PERCENTAGES (THE AMOUNT IN 

 THE UNMANURED SOIL is TAKEN AS 1 IN EACH CASE). 



the total potash, i.e., inclusive of that insoluble in strong 

 acids, conveys no idea at all of difference in the capacities 

 of the soils, for the difference in the amounts in the several 

 plots is barely perceptible. Dyer concluded that, as a 

 general rule, soils which contain less than O'Ol per cent. 



