absorption as measured by leaf analysis. The total quantity of nutrients absorped 

 will vary with vigor, but not all of these differences are related to vigor. 



"Let us assume that an increased amount of fertilizer will be needed as we 

 increase the number of trees per acre. Especially when we consider that until 

 the orchard matures, we normally do not apply fertilizer over the entire orchard 

 floor. As a greater percentage of the orchard floor is occupied by trees, a 

 greater amount of fertilizer will be applied. Normally, the fertilizer suggestion 

 would be to apply sufficient nitrogen to maintain the desired tree vigor. 



"Some of our results agree with other reports, from England for example, and 

 some of our results are new and different. The study I will refer to was con- 

 ducted as a doctorate research problem by one of our graduate students - Mr. 

 Marcel Awad from Lebanon. This study involved Delicious, Jonathan, Mcintosh and 

 Northern Spy on East Mailing I, II, V, VII, XIII and XVI. Nutrient absorption 

 was measured by leaf analysis. Fruit from Delicious, Jonathan and Mcintosh were 

 non-bearing age. 



Nutrient Absorption 



"Nitrogen - This element did not give any consistent difference of practical 

 importance. Thus, the trees themselves would contain the same amount of nitrogen 

 regardless of rootstock. However, the amount applied should vary according to 

 the number of trees per acre. Perhaps not in direct proportion to the number of 

 trees but Increased somewhat as number of trees per acre increase. 



"Potassium - EM II and V were lowest in potassium. EM VII, XIII, and XVI 

 were intermediate and EM I was highest. This suggests, as previously reported, 

 that trees growing on EM I would be least susceptible to potash deficiency. If 

 planted on soils lon7 in potash, the deficiency would develop first for the 

 EM II and V rootstocks. This would mean also, that larger amounts of potash 

 would need to be applied to trees on EM II and V while trees on EM I may require 

 considerably less potash. 



"Phosphorus - There were no consistent differences although EM V and VII 

 showed somewhat higher phosphorus. There appears to be no consistent difference 

 in the phosphorus absorption or requirement between rootstocks. 



"Calcium - There were no consistent differences in calcium absorption and 

 apparently the different rootstocks were essentially equal in their ability to 

 absorb this element. 



"Magnesium - Relatively large differences in magnesium absorption were ob- 

 served between rootstocks. EM XVI x^as high and EM I and VII low. This confirms 

 other reports suggesting that trees on EM I and VII may be susceptible to 

 magnesium deficiency. This situation is readily detected by leaf analysis and 

 easily corrected by use of epsom salts sprays or applications of doloniitic lime 

 and other materials containing magnesium. 



"Manganese - Again, relatively large differences were found. EM II was 

 lowest and EM XIII highest. This need not be of any particular concern because 

 the differences were not great enough to result in manganese toxicity first. 

 However, on soils having large amounts of available manganese, Delicious trees on 



