MAINTAINING FERTILITY OF LAND 197 



less if erosion is prevented and if farm manure is all 

 saved and is so handled as to prevent loss by leaching 

 before it is used. 1 



The soils in arid regions are usually more troubled with 

 alkali than with a shortage of minerals. 



AMOUNT AND VALUE OF FARM MANURE PRODUCED 



127. Fertilizing value of food and of manure. From 

 65 to 75 per cent of the nitrogen, phosphoric acid, and 

 potash fed to cows is recovered in the manure ; with fat- 

 tening animals, 85 to 95 per cent is recovered. In general, 

 it is safe to assume that three-fourths of the fertility in 

 the feed is recovered in the manure. This, of course, 

 assumes that the liquid portion is saved and that leach- 

 ing and other losses are prevented. On most farms, half 

 of the value is lost. From one-third to one-half of the 

 organic matter is recovered, but over half of this is usually 

 lost when manure is left in piles or in the barnyard. 



128. Amount and value of manure produced by farm 

 animals. A 1200-pound horse will produce about 

 eleven tons of excrement per year, which, together with 

 the bedding, will make about fourteen tons of manure. 

 A cow produces a little more, but about the same amount 

 of dry matter. Steers fed at the Ohio Station averaged 

 at the rate of nine tons per year. An equal weight of 

 sheep produces fewer tons, but the manure is drier, so 

 that about the same amount of plant-food is produced. 

 A fairly safe rule for any stock, except poultry and hogs, 

 is to count one ton per month for each 1000 pounds of 

 animals kept. To purchase an equal amount of plant- 



1 For a discussion of the use of fertilizers, see any book on soils, or 

 Elements of Agriculture, G. F. Warren, pp. 107-147. 



