Much less N is being applied in orchards than in the past because of the 

 reduction or elimination of grass and weed competition by the use of her- 

 bicides. Furthermore, apple trees conserve N by translocating part of the 

 nitrogenous material in senescing (aging) flowers and leaves to adjacent 

 bark and wood tissue. The N becomes part of the protein fraction. The pro- 

 tein levels in shoot bark and wood decrease rapidly before bud-break in the 

 spring. This decrease is accompanied by increased levels of soluble N. 

 Thus, this N is available to help support growth in early spring when con- 

 ditions for root uptake are poor. 



Potassium (K) is the most abundant nutrient in the fruit. Therefore, 

 the level of cropping greatly influences the demand for K. In contrast, 

 very small amounts of calcium (Ca) are found in the fruit and this repre- 

 sents a small proportion of the total uptake of this element, emphasizing 

 that one of the problems of Ca nutrition is that of distribution in the 

 tree. Fruit are often Ca-deficient when leaves have sufficient Ca. The 

 effects are described in a following article (pages 14 and 15). 



Manganese (Mn) . In the spring, 1984 issue of Fruit Notes , it was stated 

 that Mn is the most frequently deficient elemerTE in apple trees. This 

 statement was in error! Low Mn is the most frequent foliar symptom of defi- 

 ciency seen in Massachusetts. However, foliar symptoms of Magnesium 

 deficiency have become increasingly prevalent the last 3 or 4 years. 



A standard for apple tree growth . Vihile the amount of growth made by a tree 

 "Ts dependent on several factors, some of which cannot be controlled by the 

 grower, it is desirable to set up standards to strive for. The stronger 

 shoots of young bearing trees 5 to 10 years of age should make 15 to 20 

 inches of growth each season. Older trees should have many shoots which 

 make 8 to 10 inches of growth. Thickness of shoot growth is <'ully as impor- 

 tant as length. Stocky shoots are the sign of a vigorous tree while slender 

 shoots indicate a poor, under-nourished tree. 



***** 



POMOLOGICAL NOTES 



V/illiam J. Lord 



Plant trees early . Tree roots will grow when the soil temperature reaches 

 about 45oF. Thus, early planting allows the roots to become established and 

 to make growth before high air temperatures cause rapid growth above ground. 



CHEMICAL THINNING OF EMPIRE . It is well known that trees of this variety 

 tend to produce only medium-size fruit. For example, fruit on young trees 

 in experimental plots in 1982 and 1983 averaged only 2 1/2 inche"s Tn 

 diameter partly because of excessive fruit set. Thus, questions have arisen 

 concerning chemical thinning of Empire. Based on a thinning trial in 1982 

 and 1983 by Dr. Duane Greene, we tentatively suggest an application of NAA 

 pi'js 1 lb. of sevin, 50% V/P or its equivalent. 



