through mid-July of 1966. Therefore, it was of interest to determine 

 the zinc content of the grass and soil under the treated trees. The 

 results of these analyses are shown in Table 3 . 



Table 3. Zinc level in grass and soil under Northern Spy trees after 

 receiving a soil application of zinc sulfate. 



^^..^ Cppm) ifl Zinc in soil (ppm) on 9/1/55 at depths of:" 

 - 9/1/56"^ 0-1" 1-2" 2-3" 3-1+" 4-5" 5-6" ( 



Zinc 

 Treatment-" grass 9/1/56^ 0-1" 1-2" 2-3" 3-4" 4-5" 5-6" 6-8" 



Zn SO4 69.2 

 Check 27.9 



Ten lbs. zinc sulfate applied April 14, 1955 

 2Ten trees per treatment 

 ■^Average of 5 treated and 5 untreated trees. 



It can be seen in Table 3 that the zinc level of the grass in 1966 

 was increased by the soil application of zinc sulfate on April 14, 1965, 

 and that most of the zinc is apparently fixed in the top 2 inches of 

 soil. Why the zinc content of the apple leaves was not increased is not 

 known. However, these data and the leaf analyes from several other 

 trials of 1-year duration make us question the value of soil applications 

 of zinc. 



Summary 



In preliminary trials, mean zinc levels in some Massachusetts apple 

 orchards were found to be 15.0 ppm in 1965, and 12.4 ppm in 1966. Al- 

 though some trees may be low in zinc, at present no visual deficiency 

 symptoms have been observed and consequently zinc treatments are of 

 questionable value in most orchards. The data also suggest that soil 

 applications of zinc sulfate may be of no immediate value in raising the 

 zinc level in apple leaves. 



*************** 



1967 GUIDE TO ORCHARD FERTILIZATION 



W.D. Weeks 

 Department of Plant and Soil Sciences 



Our basic suggestions for orchard fertilization have not changed 

 from past recommendations. Nitrogen is still the key to a satisfactory 

 fertility program and the rate of application to each tree should be 

 adjusted to give the maximum yield of firm, highly colored fruit. A 

 careful study of tree growth during the growing season and a check of 

 the fruit at harvest can be most helpful in determining the nitrogen 

 requirements of the tree. 



