l66 SOILS AND FERTILIZERS 



tons per acre are usually sufficient. It is better 

 economy to make frequent light applications than 

 heavier ones at long intervals. When manure is 

 spread frequently the soil is kept in a more even state 

 of fertility, and losses by percolation, denitrification, 

 and ammonification are prevented. 



For growing garden crops 20 tons and more per acre 

 are sometimes used. It is better, however, not to use 

 stable manure too liberally for trucking, but to supple- 

 ment it with special fertilizers as the crop may require. 

 Soils which contain a large amount of calcium car- 

 bonate admit of more frequent and heavier applications 

 of manure than soils which are deficient in this com- 

 pound. The lime aids fermentation and nitrification. 



203. Crops Most Suitable for Manuring. — Soils 

 which contain a low stock of fertility will admit of 

 manuring for the production of almost any crop. 

 Soils well stocked with plant food, like some of the 

 western prairie soils, which are in need of manure 

 mainly for the physical action, will not admit of its 

 direct use on all crops. On a prairie soil of average 

 fertility an application of well-rotted manure will 

 cause wheat to lodge. When it cannot be applied di- 

 rectly to a crop, it may be used indirectly. It never 

 injures corn by causing too rank a growth, and when 

 wheat follows corn which has been manured there is 

 but little danger of loss from lodging. 



