EFFECTS OF NITROGEN AND POTASSIUM ON RUSSET OF GOLDEN DELICIOUS: 



A PROGRESS REPORT 



Mack Drake, John H, Baker and James F. Anderson 

 Department of Plant and Soil Sciences 



A nitrogen and potassium fertilizer study was begun in a 10- 

 year-old Golden Delicious block in 1964, in cooperation with J. A. 

 Davis and Sons, Sterling Junction, Massachusetts. Before treatments 

 were initiated, leaf analysis and trunk circumference were used in 

 selecting and grouping trees. Nine treatments were established. 

 Consisting of 3 levels of applied nitrogen with 3 levels of applied 

 potassium in 6 replications. Results to date are as follows. 



Initially, leaf nitrogen and potassium were relatively high. 

 After 4 years of treatment, low, medium and high ranges of leaf ni- 

 trogen and potassium are developing (Table 1), but a greater spread 

 between low and high is desired. 



Table 1. Leaf nitrogen and potassium (% dry weight) as influenced 



by annual applications of nitrogen and potassium fertilizer 



1965 

 2.00 



N2 2.06 



T 

 e s p e c i 

 ferti 1 

 gen tr 

 in 196 

 and 12 

 1 eaf n 

 that a 

 the de 

 with f 

 are be 



"3 



ime i 

 ally 

 i zed 

 eatme 

 7. T 

 % (1. 

 i trog 

 bout 

 sired 

 rui t 

 g i n n i 



2.19 



1967 

 1.97 



2.02 



2.23 



K. 



1965 

 1.58 



1.66 



1.65 



1967 

 1.78 



1.88 



2.00 



s required to produce a wide spread in leaf analysis, 

 in this case where we started with trees growing on well 

 soil. The leaf nitrogen spread between low and high nitro' 

 nts was about 9.5% (2.00-2.19) in 1965 and 13% (1.97-2.23) 

 he leaf potassium spread was about 4% (1.58-1.65) in 1965 

 78-2.00) in 1967. Thus, the spread between low and high 

 en and potassium is increasing with time. We estimate 

 4 additional years of treatment are needed to establish 



range in leaf nitrogen and potassium for correlation 

 quality. Nevertheless, some differences in fruit quality 

 ng to appear among the treatments. 



Russet : In 1966, the late Dr. W.D. Weeks observed a trend in rus- 

 seting among the treatments and this was confirmed in 1968. A ran- 

 dom sample of 30 apples from each tree was scored for russet in 

 November, 1966, by Dr. Weeks and in November 1968, by James F. 

 Anderson. Each apple was scored as light, medium or severe in rus- 

 set, based on area covered and severity of roughness. 



