MANURING AND FERTILIZING 37 



Wisconsin Experiment Station twenty loads per acre 

 were applied, and larger quantities in Great Britan. 



It seems natural to assume that the beneficial effe<5ls 

 of manure must largely be due to other causes than 

 the addition of plant-food. Among these may be its 

 influence on the physical properties of the soil, render- 

 ing it more retentive of moisture, more porous and 

 more permeable for air and roots, and a better home 

 for the useful soil badleria, which, in fact, it may sup- 

 ply. The decomposition of such quantities of organic 

 matter, with the consequent liberation of carbon dioxid, 

 aids in rendering the mineral resources of the soil more 

 available. Generally speaking, it is more economical 

 to apply about ten tons of manure per acre and supple- 

 ment it with fertilizers, except upon loose open soils 

 of poor texture, where the beneficial effedl from the 

 larger amount should probably be ascribed to its in- 

 fluence upon the retention of moisture. It is preferable 

 that the manure be rotted somewhat and applied the 

 previous fall, while the fertilizers may be applied when 

 planting. On some soils, to reduce the danger of dis- 

 ease, it may be advisable to apply all the barn manure 

 to the previous crop. The application of fertilizers is 

 profitable under most conditions in the Eastern and 

 North Central States. At New Hampshire Experi- 

 ment Station the application of fifteen cords of manure 

 increased the 3'ield of marketable potatoes over 100 

 bushels per acre compared with no manure, and the 

 use of 1 ,500 pounds of fertilizers with the same amount 

 of manure resulted in a further increase in yield of 

 130 bushels per acre.' Taft,'^ of Michigan, shows that 



' N. H. Bui. Ill, p. 116. 2 Mich. Bui. 131, p. 10. 



