MANURES. 251 



an element of the ashes of plants is by no means slight, as will be 

 shown by the following table giving the amount of potash removed 

 from the soil by various crops : — * 



I o bushels of wheat 3 lbs. 



1,200 lbs. of wheat straw 9 " 



10 bushels of rye 2.L " 



1,600 lbs. of rye straw 1 1 « 



10 bushels of corn 2! " 



I ton of corn stalks 8 " 



10 bushels of oats if «< 



1,700 lbs. of oat straw 12 « 



10 bushels of beans 5^^ " 



1,100 lbs. of bean straw 36 " 



ton of turr 



'Ps 7 



700 lbs. of turnip tops 5 



I ton of potatoes 28 



ton of red clover 



I ton of meadow hay 18 " 



I ton of cabbage r " 



Assuming the production of a farm to be 500 bushels of wheat, 

 100 bushels of rye, 10 tons of turnips, 40 bushels of potatoes, lO 

 tons of clover hay, and 20 tons of meadow hay, and assuming the 

 production of the grain to require the proportion of straw stated 

 above, the amount of potash taken from the soil in a single year 

 would be about 2,500 lbs., being the amount contained in over 

 1,000 bushels of unleached oak wood ashes, and worth, according 

 to Professor Johnson's estimate, about $100. 



This is not an unusually large estimate for the production of any 

 good farm ; and the amount of potash removed is more than the 

 amount returned in the form of purchased manure in any twenty 

 years to an average farm in New England. 



The sources from which potash may be most advantageously 

 obtained by the farmer are wood ashes — leached or unleached — 

 green sand marl, sea-weed, and swamp muck. 



The most universally accessible source, in any new country 

 like this, is, of course, wood ashes. And such as have not been 



* Small fractions are disregarded, as it is only desired in this connection to show gen- 

 eral results. 



