SUGGESTIONS FOR FERTILIZATION OF APPLE TREES IN 1973 



William J. Lord 

 Department of Plant and Soil Sciences 



More growers participated in our leaf analysis program in 

 1972 than in any previous year. Thereby, we obtained considerable 

 information concerning the nutritional status of our apple trees 

 which is discussed below in conjunction with fertilization sugges- 

 tions for 1973. 



Although leaf analysis is a valuable tool for determining nu- 

 tritional status of fruit trees, it is no substitute for careful 

 observations of tree growth, fruit size, and fruit color when de- 

 ciding the amount of nitrogen to apply. In the case of the other 

 essential elements, however, leaf analysis is the best means of 

 determining if their levels in trees are low or excessive. 



The essential elements for apple trees are supplied either by 

 foliar or soil applications. However, we think it is safest to ap' 

 ply all elements as a fertilizer except in emergency cases because 

 foliar sprays may be more expensive, be of no benefit, or could 

 damage fruit. 



Nitrogen (N): N is Still the key to a satisfactory fertility pro- 

 gram. The desirable N content of leaves from bearing 'Mcintosh' 

 apple trees is 1.80-2.10%. In 1972, 56% of the leaf samples from 

 bearing trees of this cultivar exceeded 2.10%. The remaining sam- 

 ples, with one exception, were within the desirable range. A lim- 

 ited number of leaf samples from young 'Mcintosh' trees (10 years 

 of age or less) averaged 2.24% N and some samples from bearing 

 'Delicious' trees averaged 2.25%. 



Since apple trees are showing abundant 

 eating a potentially good crop for 1973, we 

 1973, growers should: 



flower buds, thus indi- 

 are suggesting that in 



1. 

 2. 



Apply 

 Omit 

 of 'Mc 

 in 19 7 

 Reduce 

 they a 

 si vely 

 b e a r i n 

 2.6%, 

 start 

 Apply 

 orous . 

 are pr 

 the tr 



no mor 

 r redu 

 Intosh 

 2. 



or om 

 re sta 



1 arge 

 g 'McI 

 but th 

 to pro 

 suf f i c 

 N le 

 obably 

 e e V i g 



e than normal 

 ce N applicat 



rates of N. 

 ions by one-half in those blocks 

 trees which produced fruit with poor color 



it N on young 

 rting to bear 

 , poorly colo 

 ntosh' apple 

 ese high N le 

 duce . 



ient N to kee 



vels of 2.2-2 



sati sf actory 



orous in orde 



, vigorous 'Mcintosh' trees if 

 a crop in order to avoid exces- 

 red fruit. Young, vigorous, non- 

 trees may have N levels of 2.4- 

 vels should be reduced when trees 



p bearing 'Delicious' trees vig- 



.4% in bearing 'Delicious' trees 



because it is necessary to keep 



r to produce large-sized fruits. 



