CONSERVATION OF FERTILITY 245 



Mechanical loss in material 



purchased $% T 9 J 4 Io 



Sold from farm 1278 676 380 



Loss in food consumed, etc.. 128 53 144 



Total 1425 743 534 



Food and fuel purchased 625 470 375 



Balance lost from farm 800 273 159 



The manure produced and used on this farm results 

 in the production of larger crop yields than is the 

 case with exclusive grain culture. The nitrogen 

 gained by the clover and peas more than balances the 

 loss of nitrogen in other crops. Experiments have 

 shown that a rotation similar to this caused an in- 

 crease in soil nitrogen. 18 Manure, meadow and past- 

 ure all tend to increase the soil's humus and nitrogen. 

 The losses of phosphoric acid and potash are exceed- 

 ingly small, averaging about a pound per acre for 

 each. The action of the manure on this farm is con- 

 tinually bringing into activity the inert plant food 

 of the soil so that every year there is a larger amount 

 of more active plant food, which results in producing 

 larger yields per acre. 



The method of farming has a marked effect upon 

 crop yields. The average yield of wheat in those 

 counties in Minnesota where live stock is kept and 

 crops are rotated, is over 10 bushels per acre greater 

 than in similar counties where exclusive grain farm- 

 ing is followed. 



