BARNYARD, STABLE, GREEN MANURES 87 



cistern. The cistern method of saving liquid manure is of doubtful econ- 

 omy in this country. The expense of cisterns and the trouble of hauling 

 and distributing, together with the care which must be exercised to pre- 

 vent loss of nitrogen by fermentation of the liquid when it stands long, 

 are all valid objections to such provisions. It is possible under intensive 

 farming and with cheap labor that liquid manure might be thus saved 

 and utilized for crops that respond to nitrogenous fertilizers. Best results 

 with manure demand that the liquid and solid portions be applied together. 

 It is the consensus of opinion that the best general practice is to save the 

 liquid by the use of absorbents. 



Since nitrogen frequently escapes as ammonia, certain absorbents 

 for gases, such as gypsum, kainite, acid phosphate and ordinary dust, 

 have been recommended. As direct absorbents, however, these are of 

 doubtful value, although some of them are effective, first, in reducing the 

 fermentation, and second, in actually reinforcing the manure by the addi- 

 tion of plant-food constituents. 



Sterilization. Preservatives have also been suggested in the nature 

 of substances that will prevent fermentation and thus reduce losses. 

 Bisulphide of carbon, caustic lime, sulphuric acid and a number of other 

 substances have been tested for this purpose. However, anything that 

 will prohibit fermentation destroys the bacteria of the manure, and such 

 destruction may more than offset the saving in plant-food constituents. 

 Furthermore, most of these materials are rather costly, and the benefits 

 derived are not equal to the expense incurred. 



Reinforcing Manures. A number of substances have been used to 

 reinforce manure. The one most beneficial and economical is either acid 

 phosphate or rock phosphate. This is undoubtedly due to the fact that 

 phosphorus is the element most frequently needed in the soils, and that 

 manure is inadequately supplied with it. The following table, showing 

 results obtained at the Ohio Experiment Station by reinforcing manure 

 with different substances, gives direct evidence as to the relative merits 

 of such substances: 



VALUE OF MANURE, AVERAGE 15 YEARS. Rotation: Corn, Wheat, Clover (3 Years). 



It is evident from the above table that all the materials used have 

 more or less increased the value of the manure, as determined by the 

 value of increase in crops obtained from each ton when applied once in a 

 three years' rotation of corn, wheat and clover. The value per ton of 



