306 Bacteria in Relation to Country Life 



contain about one-half of the total nitrogen and about 

 three-fourths of the total potash originally present in 

 the food of milch cows. In the case of sheep, it has been 

 found that the liquid excreta contained nearly one-half 

 of the potash and from one-half to three-quarters of the 

 nitrogen voided by the animals. 



These figures show that a large proportion of the 

 nitrogen compounds in animal excreta are soluble and 

 subject to rapid decomposition. Severin, who isolated 

 a number of bacteria from manure, found that certain 

 species which grew readily in the liquid excreta refused 

 to develop in the solid excreta. When, however, both 

 the solid and liquid excreta were present, the organisms 

 developed readily and attacked the former as well as 

 the latter. 



This indicates that, in manure properly protected 

 from the leaching action of rain, the decomposition of 

 the comparatively inert substances in the solid excreta 

 and the litter proceeds more rapidly on account of the 

 soluble nitrogen compounds which enable the bacteria 

 to grow vigorously and to attack also the insoluble 

 materials. 



LOSSES FROM FARMYARD MANURE 



The value of farmyard manure in stimulating crop 

 growth is due to its organic matter, to its plant-food 

 constituents, and to some extent, also, to its bacteria. 

 A ton of farmyard manure of average composition adds 

 to the soil 425 pounds of organic matter, 10 pounds of 

 nitrogen, 7 pounds of phosphoric acid, 9 pounds of potash 

 and a countless number of bacteria. The organic matter 



