154 SOILS AND FERTILIZERS 



196. Rate of Application. The amount of manure 

 that should be applied depends upon the nature of the 

 soil and the crop. On loam soils intended for general 

 truck purposes heavier applications may be made than 

 when grain is raised. For general farm purposes, 6 

 to 8 tons per acre are usually sufficient. It is better 

 economy to make frequent light applications than 

 heavier ones at long intervals. When manure is 

 used frequently the soil is kept in a more even state 

 of fertility, and losses by percolation, denitrification, 

 and ammonification are prevented. Too often the 

 manure is not evenly distributed about the farm, fields 

 adjacent to stables are heavily manured, while those 

 at a distance receive none. 



For growing garden crops 20 tons and more per 

 acre are sometimes used. It is better, however, not 

 to use stable manure in excess for trucking, but to 

 supplement it with special fertilizers as the crops may 

 require. Soils which contain a large amount of cal- 

 cium carbonate will not become acid when farm ma- 

 nure is used, and hence admit of more frequent and 

 heavier applications than soils which are deficient in 

 this compound. The lime aids fermentation and ni- 

 trification. 



197. Crops Most Suitable for Manuring. Soils 

 which contain a low stock of fertility admit of manur- 

 ing 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 

 its physical action, will not admit of its direct use on 



