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apples are softer and show greater "break down after removal from storage. Other 

 research woi'kers have reported that pears from non-irrigated trees pressure tested 

 higher and had more total solids than those from irrigated trees, but when the 

 fruits were in prime eating condition no difference in texture and flavor could te 

 detected. In Maryland, it was found that when moisutre deficiency occurred during 

 the latter part of the growing season there vas a reduction in red color develop- 

 ment on apples, "but in years when soil moisture was ample at harvest time, the 

 non^irrigated trees produced "better color fruit than did the irrigated trees. In 

 addition, it was found that when moisture shortage occurred not latter than early 

 July, fruit "bud formation appeared to "be increased. In the same experiment water 

 shortage from late July until fall had no apparent effect on flower bud formation. 

 In greenhouse studies conducted in Michigan, It was foiind that utilization of SC^ 

 cr more of the available soil moisture significantly reduced total chlorophyll per 

 apple tree, shoot growth, trunk diameter increase, dry weight increase, and leaf 

 area. 



Present Outlook 



This brief review summarizes a few of the studies previously conducted on the 

 soil raoistxire relationships of fruit trees. Experimental results have shown that 

 growth of apples was not reduced until soil moisture was near or at permanent wilt- 

 ing. In other words the growth of apples was not reduced until the tree roots had 

 used most of the available moisture in the soil. On the other hand, the growth of 

 the fruit trees was affected prior to the depletion of available soil moisture. 



At present, little is known about the Irrigation needs of Massachusetts orchards. 

 How many years out of ten would irrigation pay? Even though fruit size and yield 

 might not be affected by a deficiency of soil moisture, tree growth may be signif- 

 icantly reduced and thereby have an adverse Influence on subsequent crops. This 

 can be determined only by a long term irrigation project such as is being planned. 



Nutritional status, particularly nitrogen level, influences color, keeping 

 qualities of apples and fruit development and alsr might cssntrol fruit quality to 

 a greater extent than soil moisture. This project should enable us to find out 

 the nutritional status of the irrigated and non-irrigated trees and should determine 

 if part of the effects of irrigation on fruit quality can be contributed to nutrition. 



One of the most difficult problems in connection with irrigation is to determine 

 when Irrigation water should be applied in the orchard. It is hoped that the data 

 obtained from the periodic soil moisture readings and fruit growth measurements will 

 give us an Index as to when trees need irrigation. 



W, J. Lord 



I I I I I I I I I I I I I I I I 



WHEN DO APPLES EEQUIHE THimiMG? 



A mature apple tree may have 30,000 to 5C,000 blossoms. If it were possible 

 for all of these blossoms to set fruit, and to mature to an average size of I50 

 apples per box, there would be a crop of 200 to 333 boxes per tree. We all know 



