NIITRTTTONAL PROBLEMS IN 1982 

 AND SUGGESTIONS FOR FERTILIZATION OF APPLE TREES IN 1983 



Wi lliam J . Lord 

 Department of Plant and Soil Sciences 



Prospects for a heavy bloom in 1983 are not too likely follow- 

 ing the large crop in 1982. However, there are ample flower buds 

 for a good crop in 1983. 



The analysis of leaf samples from commercial orchards showed 

 that potassium (K) and magnesium (Mg) was deficient in many 

 orchards in 1982 and boron (B) was generally low. Visual obser- 

 vations of Mg deficiency were quite prevalent on both apple and 

 pear trees, which is unusual, and perhaps resulted from leaching 

 of this element by the heavy rainfall in June (9.6 inches at the 

 Horticultural Research Center). It is possible that leaching of 

 K and Mg occurred both from the leaves and soil. Mineral analysis 

 of Mcintosh fruits from 24 orchards sampled shortly prior to 

 harvest in 1982 showed that calcium (Ca) levels were low. Two 

 blocks of trees in each orchard were sampled. Only 5 of the 24 

 orchards produced fruit in both blocks with Ca levels high enough 

 to clearly predict that their fruit had a high potential for long- 

 term storage of good quality fruit. 



Information on the Leaf Analysis Reports indicated that some 

 growers continue to apply a "complete fertilizer". Cost could be 

 reduced by using fertilizer that contains no phosphorous (P) since 

 there is no evidence that our apple trees need this element beyond 

 what is present in the soil. 



With the above observations in mind, we present the following 

 suggestions as a guide for fertilization in 1983. 



Nitrogen (N) : Most orchards had a large crop in 1982, there- 

 fore! the trees may be low in available N for utilization this spring, 

 We suggest higher rates than normal of N this year unless the trees 

 were excessively vigorous in 1982 or were heavily pruned this past 

 winter. 



Potassium (K) : Over 901 of the leaf samples were deficient, 

 probably due to the demand for this element by the large crop, and/or 

 leaching because of heavy rainfall. 



The leaf scorch symptoms of K deficiency may be confused with 

 the leaf margin burn from calcium chloride sprays. However, unlike 

 leaf burn from calcium chloride sprays, the scorch of leaf margins 

 due to K deficiency progresses from the older leaves to the younger 

 leaves of current season shoots as the season advances. The scorch 

 may turn gray in color and leaf fall may occur late in the growing 

 season . 



