SOIL IMPROVEMENT 77 



for plants because of the three fertilizing elements which 

 it contains, nitrogen, phosphoric acid, and potash. These 

 are the three elements of plant-food of greatest value to 

 plants. Another benefit is from the vegetable matter con- 

 tained in the manure, which is a great source of humus. 

 This helps to put the soil into better physical condition and 

 makes a better home for soil bacteria. The decay of the 

 vegetable matter sets up certain chemical changes which 

 are of benefit to the soils and crops. 



Value of Manure. — The value of barnyard manure 

 depends on several conditions : 



The age and kind of animals. 



The kind and amount of feed they eat. 



The amount and kind of litter or bedding used. 



The care of the manure after it is made. 



The age of the manure. 

 When compared with the market prices of commercial 

 fertilizers the average value of manure from the barn of a 

 horse or mule in a year is estimated at $27; a cow, $19; 

 a hog, $12; a sheep, $2. To get these values the manure 

 must be used to the best advantage. 



When equal weights of manure are considered the values 

 from the different kinds of farm stock would usually be in 

 this order: Poultry, sheep, pigs, horses, cows. 



Loss in Manures. — Manures are liable to lose their value 

 during storage from two direct causes: 



Ilrst, heating, when left in heaps in the barnyard or in 

 the field. This results in the loss of nitrogen. Manure must 

 not be allowed to get hot from its own fermentation. 



Second, leaching, when left where water can wash it. 

 This may take away much of the valuable plant-food. When 

 manure is allowed to leach the most valuable parts are lost 

 first. 



Extremes in moisture and temperature should not be 

 allowed if manure is to be saved. There is very little loss 



