98 Barn and Field Experiments in 1916 



od affords a satisfactory and economical way of conserving 

 the plant food in the feeds used. It is a conservative estimate, 

 then, that the plant food in the manure annually voided by farm 

 animals and poultry in Maine has a potential value of about ten 

 millions of dollars and that it is doubtful if by present methods 

 of care even one-half of this plant food is actually returned 

 to the soil. These trials with the manure platform and swine 

 indicate that by a little care most of this plant food can be 

 conserved and that the profit on the swine will make good re- 

 turns on the investment and the added plant food saved will 

 all be clear profit. And this conserved plant food will in many 

 cases be the difference between keeping livestock at a profit or 

 keeping them at a loss. 



What Is Farm Manure Worth To The Farmer? 



The Ohio Experiment Station has carried extensive com- 

 parative experiments with farm and commercial manures for 

 many years. Recently Director Thorne wrote : "After more 

 than twenty years' work in the comparison of manure and 

 chemical fertilizers on many crops, the Station is not able 

 to credit manure with any value beyond that of the nitrogen, 

 phosphorus, potassium and lime which it carries." "When 

 manure costs more than two dollars per ton spread on the land, 

 it is wiser to use the chemical fertilizers mentioned than to 

 buy manure." 



In addition to the nitrogen, phosphoric acid and potash 

 which farm manure supplies it also carries a large amount of 

 organic matter which is important in increasing the produc- 

 tivity of the soil. As this vegetable matter breaks down in 

 the soil the acid products thus formed helped to dissolve and 

 make available to plants some of the otherwise insoluble plant 

 food in the soil. Farm manures teem with bacteria of various 

 kinds which cause chemical changes not only in the manure, 

 but in the soil itself, converting insoluble plant food into forms 

 available for the use of crops. The humus formed from the 

 organic matter of farm manure improves the soil texture, 

 helps retain moisture, and is valuable in many ways. Its plant 

 food is not so quickly nor so completely available as in the 

 better forms of chemicals. But after much balancing of the 



