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Nature-Study Agriculture 



Screening 

 manure 

 from flies 



The money 

 value of 

 manure as 

 plant food 



Other 

 value ; 

 humus 



main reason why we should do all that we can to keep 

 them from increasing. (Exp. 9.) The chief breeding 

 place of flies is the manure pile. (Exp. 8.) The eggs 

 are laid there, and in a day or two hatch as tiny white 

 larvae (maggots), which form pupae that soon turn into 

 flies (Figs. 144, 145, 146, and 147). Removing the 

 breeding places of flies is of more value than killing 

 thousands of the insects. It is the only way to de- 

 stroy flies effectively. It is a simple matter to keep 

 stables clean and to have the manure heap covered 

 and closely screened to keep the flies from laying 

 their eggs there. Many careful farmers also screen 

 their barns as they do their houses. 



Good average manure mixed with straw that has been 

 used for bedding contains about seven pounds of phos- 

 phate fertilizer and about ten pounds each of nitrogen 

 and potash to the ton. Now, the ordinary market value 

 of phosphate and potash in commercial fertilizer is 

 5 cents a pound, and the price of nitrogen is about 15 

 cents a pound. On this basis the phosphate in one ton 

 is worth 35 cents, the potash 50 cents, and the nitrogen 

 $1.50. This would make the plant food in a ton of 

 manure worth $2.35. 



We must remember, however, that manure has im- 

 portant uses in the soil besides supplying plant-food ma- 

 terials. It becomes changed into humus, making the 

 soil more porous and spongelike, so that it receives and 

 retains water better. It contains millions of bacteria 

 that aid in preparing plant-food materials. It serves 

 as food for the beneficial bacteria that are already in 

 the soil. 



