94 MAKING THE MOST OF MANURE 



their plant food into a permanent addition to the fertility 

 of the farm. So far as possible the clover and grass 

 together with coarse grain and corn-fodder should be 

 fed on the farm. To do this requires capital, for it im- 

 plies choice stock which will pay for its feed and leave 

 the manure pile as profit. It also generally requires that 

 the farmer on rich land shall grow something that only 

 rich soil can be made to grow, or whose production is 

 unusually difficult. Markets are always glutted with 

 crops that can be grown on poor land and with the least 

 labor. It is only by growing something that pays better 

 than the staple easily-grown crops that money can be 

 made in farming under present conditions. 



Valuable lessons are obtained from European methods. 

 The city of Berlin covers an area of 20,000 acres, and the 

 sewage farms owned and conducted by the municipality 

 cover an area twice the size. The sewage disposal prob- 

 lem has nowhere reached the development that is found in 

 Berlin. The city will ultimately sell this land at great 

 profit and then turn to some biological method of meet- 

 ing the problem or secure more land and go on with the 

 work of land reclamation in connection with the disposal 

 of the city's accumulations. The prevailing mode of dis- 

 posing of sewage by pouring it into streams is exceed- 

 ingly wasteful. It represents so much nitrogen which 

 has been extracted from the soil, and which ought, by 

 right, to be returned to the soil. If it could be advan- 

 tageously used, it would represent a value of about 

 $200,000,000 a year to England alone. This, however, 

 is distributed over a quantity of three billion tons. Sew- 

 age is so complex in its nature that the recovery of its 

 chemical constituents would be almost a hopeless task. 

 That, however, is no reason why some methofl should 

 not be devised of utilizing it as a fertilizer. Farmers 

 have endeavored to use the sludge as a fertilizer ; but that 

 is not always practicable, partly because of the chemical 



