SUGGESTIONS FOR FERTILIZATION OF APPLE TREES IN 1977 



W.J. Lord and Mack Drake 

 Department of Plant and Soil Sciences 



It should be recognized from the start that it is not possi- 

 ble to give specific suggestions for fertilization in an article 

 of this nature. Therefore, the suggestions below merely serve as 

 a guide to the fruit grower for determining the fertilizer program 

 in his orchard. It is well to remember that foliar applications 

 of nutrients are merely supplements to soil applications. 



The 1977 fertilizer program will require more than usual con- 

 sideration because of winter injury to the trunks of Mcintosh trees 

 and some Delicious trees in January, 1976, and due to variable 

 fruit set this past summer. 



The bark on the winter-injured tree trunks in some instances 

 split but more generally just pulled away from the wood. Fortu- 

 nately, most growers became aware of the injury in March and April 

 and stapled or tacked the bark to the wood. Although the damage 

 was repaired, this past fall the leaves on many of the winter- 

 injured trees were light green or reddish in color in comparison 

 to those on non-injured trees. Since the trees have been weakened, 

 it is suggested that trees severely winter injured in 1976 be 

 sprayed in 1977 v\:ith urea (5 pounds/100 gallons) at about first 

 cover. Apply as a separate application. 



Fruit set was variable in 1976 with a light crop of Mcintosh 

 in some orchards and a large crop of Delicious in many orchards. 

 Regarding this, it is well to remember that the bloom and the early 

 vegetative growth in 1977 will be made largely at the expense of 

 stored foods. Trees which had only a partial crop in 1976 should 

 have a considerable reserve of nitrogen (N) available for utiliza- 

 tion this spring. Therefore, one should reduce N applications in 

 those blocks that had a light crop in 1976 . To the contrary, trees 

 that had a heavy crop in 1976 and/or those that had winter injury, 

 may be low in available N for utilization this spring. 



Nitrogen (N) . The best guide to N needs of your trees is leaf an- 

 alysis combined with observations of tree vigor, fruit set, and 

 fruit color. Growers definitely are using less N on Mcintosh than 

 in the past because we need medium-sized, well-colored apples with 

 long storage life. Some growers have now omitted N in mature 

 Mcintosh blocks for 5 to 8 years with no apparent harmful effects. 



Young vigorous trees are troublesome when they start bearing 

 a crop because of excessively large, poorly colored fruit and poor 

 keepability of fruit in storage. The reduction or omission of N 

 is frequently essential. This proceedure plus limb positioning 



