Fertilizing and Watering Trees 



15 



Dry fertilizers in holes 



Another method of fertilizing trees is to place dry fertilizers 

 in holes in the soil. Because phosphorus and potassium 

 fertilizers applied to the soil surface are not readily available 

 to the nutrient-absorbing roots of trees, these materials 

 should be placed in the soil occupied by plant roots. Contrary 

 to popular belief, approximately 90 percent of the nutrient- 

 absorbing roots of trees are not deep but are located within 

 the top 12 inches of soil. Here moisture, aeration, and 

 nutrient conditions are favorable for root growth. 



Holes can be punched in the soil with a punch bar or drilled 

 with an auger attached to an electric drill (Figure 6). Holes 

 may be drilled if the soil is dry and punched if it is wet. 



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Fk;urf. 6. A punch bar (top) or an electric drill with a soil auger (bottom) can 

 be used to prepare holes for the application of dry phosphorus and potassium 

 fertilizers. 



