98 Practical Farming 



best sources of potash, but of late years they have been 

 taken up mainly by the manufacturers of fertihzers and 

 are no longer on the general market. In many sections 

 there are deposits of marl of varying character. The 

 greensand marl is of the greatest value, since it contains 

 phosphoric acid and potash. The ordinary shell marl is 

 valuable solely for the carbonate of lime it contains, and 

 like lime in general, it improves the mechanical condition 

 of the soil. Lime in any form is not to be considered as 

 manure, however, but a reagent in bringing about changes 

 in matters already in the soil, making them available. 



Since the keeping and feeding of live- 

 Barnyard stock is of vital importance in any system 

 Manures i . f , . 



of improved agriculture, the proper saving 



and applying to the land of the droppings and urine of the 

 stock, so that there shall be as Httle loss of its plant food 

 as possible, is essential. The need for commercial fertil- 

 izers has been largely brought about by the waste of the 

 home manures during past years. And unfortunately this 

 waste is still going on all over the country, while it can be 

 very largely avoided by proper care. Careful experiments 

 have shown that in many cases fully one-half of the ma- 

 nurial value of the barnyard product is lost by improper 

 fermentation and leaching. Professor Voorhees estimates 

 that if but one-tenth part of the present waste of manure 

 were avoided (and a larger percentage is avoidable) the 

 total amount of constituents thus saved would be more 

 than equivalent to the amounts of plant food now pur- 

 chased in commercial fertilizers. 



When manure is thrown out from the stables in loose 

 piles it begins at once to ferment, and its nitrogen flies 



