-6- 



The potassium requirements of apple trees in a hea-vy crop year are high as 

 the fruit utilizes about three tiraes as much potassium as nitrogen. The quantity 

 of potassium stored by the tree which is available for utilization is extremely 

 low in comparison -urith nitrogen. Thus it is iiiiportant to supply adequate potassium 

 in a heavy crop year. 



The follovfing tables give su,:igested rc.tes of fertilizer to use which will 

 supply the nitrogen and potassium requirements of the tree in a normal crop year. 

 The rates for nitrogen are for maximum amounts and should be reduced l/3 to 1/2 as 

 succested previously. The first table presents two plans in v/hich ammonium nitrate 

 is used in combination vrlth muriate of potash or 0-15-30. The secaid table sho\fs 

 the amounts to apply of t\TO different mixed fertilizers vrtiich will supply equiva- 

 lent amounts of nutrient elements. 



Nonual Rates of Fertilizer for Bearing Apple Orchards 



Normal Rates of Fertilizer for Bearing Apple Orchards 



Potential bushel 

 yield of tree 



Less than 15 



15-25 



More than 25 



Nitrogen 

 required 



Approximate amounts per tree 



Pounds 



0.66 



0.66-1.00 



1.33-2,00 



Potash 

 required 



Pounds 



1.3 

 1.3-2.0 



2.7-U.3 



or t;-16-16 



Pounds 



13 



13-20 

 26-I4O 



Pounds 



8 



8-12 

 16-25 



The su:igested amounts of materials to apply given in the tables are for band 

 applications under the spread of the branches. .;hen the materials are broadcast 

 over the entire orchard floor it may be necessary to increase the rate of applica- 

 tion in order to obtain the same tree response as the band applications. Fertil- 

 izer 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 potassivim. 



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

 an adequate dolomitic liming program. The pH of orchard soils should be maintained 

 between 6 and 6,5 if a soil test shows that the pH of the soil is ^!,$ or beloiir, 

 magnesium sulfate sprays should be applied to prevent possible occurence of mag- 

 nesium deficiency. It takes from 3 to 5 years befoi'e dolomitic limestone is effect- 

 ive in correcting magnesium deficiency, i/hen ruacnesium sulfate sprays are used 

 apply 2 to 3 sprays of epsom salts at the rate of 20 pounds per 100 gallons of • 



