FERTILIZER FORMULAS 291 



Cautions in Using Manure. — If too much manure is placed 

 "under the row" or "under the hill" as sometimes practiced, the 

 plants are likely to suffer from lack of moisture. This is worse in 

 dry seasons. The pad of manure under the plants may prevent the 

 rise of water through capillary action. 



The remedies are to make light applications more frequently and 

 to thoroughly mix the manure with the soil by tillage implements. 

 When manure is well rotted it does not have this injurious effect. 



Fig. 203. — Effect of fertilizing a neglected orchard. Yield of fertilized row 46 barrels, 

 unfertilized row nine barrels. (Ohio Station.) 



COMMERCIAL FERTILIZERS 



Orchards and gardens, as well as field crops, often need plant 

 food supplied in the form of commercial fertilizers (Fig. 203). 

 Conditions are so variable that no fixed formulas can be followed 

 in all cases. . Soils differ widely in composition, and plants differ in 

 their needs. 



Fertilizer formulas are expressions showing the percentage 

 composition of the three main ingredients. It has nothing what- 

 ever to say about the source of the materials used. A formula 



