Suggested rates of fertilizer for normal applications to bearing- 

 age apple trees are given in the following table. 



Normal Rates of Fertilizer for Bearing Apple Orchards 



Approximate Amounts per Tree 



Potential Bu. Nitrogen Potash Ammonium Muriate 



Yield of Tree Required Required Nitrate of Potash or 0-15-30 8-16-16 



Pounds Pounds Pounds Pounds Pounds Pounds 



Less than 15 0.55 1.3 2.0 2.1 4.3 8 



15 - 25 0.56-1.00 1.3-2.0 2.0-3.3 2.1-3.3 4.3-6.6 8-12 



More than 25 1.33-2.00 2.7-4.3 4.0-5.0 4.5-7.9 9.0-14.3 16-25 



The suggested amounts of materials to apply in the table are for 

 hand applications under the spread of the branches. When the materials 

 are broadcast over the entire orchard floor, it may be necessary to in- 

 crease the rate of application in order to obtain the same tree response 

 as with the hand applications. Fertilizer materials other than those 

 given in the tables may be used so long as they are applied at rates 

 which provide equivalent amounts of nitrogen and potassium. 



The tree's magnesium and calcium requirements can best be met by 

 maintaining an adequate dolomitic liming program. The pH of orchard 

 soils should be maintained between 6 and 5.5. If a soil test shows that 

 the pH of soil is 5.5 or below, magnesium sulfate sprays should be applied 

 to prevent possible occurrence of magnesium deficiency. It takes from 

 three to five years before dolomitic limestone is effective in correcting 

 magnesium deficiency. When magnesium sulfate sprays are used, apply two 

 to three sprays of epsom salts at the rate of 20 pounds per 100 gallons 

 of water. These sprays should be timed by calyx, first and second cover 

 sprays. To avoid possible incompatibilities, the epsom salt sprays should 

 not be combined with the regular insecticidal and fungicidal sprays. 



Boron should be applied to orchard soils every three years. Borax 

 is the most common material used. The rates of application per tree vary 

 with age and size. Apply one -quarter pound of borax to young trees, one- 

 half to three-quarters pound to medium age and size trees, and three- 

 quarters to one pound to large or mature trees. Boron may be applied as 

 a foliar spray. On an annual basis Polybor-2 or Boro Spray is applied 

 at one -half pound per 100 gallons of spray one and three weeks after petal 

 fall. 



The amounts of fertilizer applied to trees which have received annual 

 applications of 200 pounds or more of hay mulch per tree may be materially 

 reduced or entirely eliminated. Tree performance should serve as a guide 

 in determining the extent to which the rates of fertilizer may be reduced. 



It is suggested that the need for minor elements be established be- 

 fore making extensive corrective treatments. Limited trials indicate 

 that soil applications of zinc may not be effective in improving the zinc 

 nutrition of the tree. While we have no evidence of widespread micro- 

 nutrient deficiencies such as zinc and manganese, it is possible that 

 some orchards may be approaching low levels of these elements. Studies 

 in Maine indicate that when mild cases of these deficiencies occur, fung- 



