The objects of the experiment are as follows: (1) to determine how many- 

 years out of 10, apple trees on the experimental site suffer for lack of V7ater, 

 (2) to study the effect of water shortage on the growth of trees, fruit growth, 

 color, quality and yield of fruit, (3) to determine at what percentage of avail- 

 able soil moisture irrigation water should be applied and (4) to find how the 

 nutritional status of the fruit trees is effected by irrigation. 



On May 25, 1956, a frost killed 957, of the blossoms and therefore the trees 

 were not irrigated. However, in May, 1957, the trees had a snow-ball bloom and 

 a large potential crop. During June, 1957, 5.7 inches of rain were recorded x^ith 

 l.A inches on the 19th and 3.09 inches from the 26th through the 30th. However, 

 only 1.38 inches were recorded in July and 0.84 inches in August. Many parts of 

 the State were not so fortunate receiving little or no rain during June. The 

 summer of 1957 at Boston, based on the June, July and August period, was the 

 driest in 140 years of official and unofficial records. Total rainfall was but 

 3.97 inches, only 40% of the 3 month normal of 9.89. 



Yield and Fruit Size 



The fruit on the irrigated and non- irrigated trees grew approximately at the 

 same rate until after July 23rd which is 7 days after the date of the first 

 irrigation during which 3 inches of water was applied. Water was again applied 

 on August 22. Due to the slow development of red color the fruit was "spot- 

 picked" on September 17th and 18th and picked clean on September 23rfi. The 

 average yield for the irrigated trees was 29.6 bushels and that for the non- 

 irrigated trees 25.9 bushels. A greater difference in yield might have occurred 

 except for the fact that the irrigated apple trees were slightly smaller in size. 

 Fruit drop was recorded but no difference existed between the irrigated and non- 

 irrigated trees. 



On the day the fruit was picked clean, water core v/as noted in some of the 

 fruit on the irrigated trees. Approximately 15 per cent of the fruits from the 

 irrigated trees had x-zater core and only 1 per cent of those from non- irrigated 

 trees. 



At harvest 4 bushels of apples xvrere selected from each tree to determine 

 the average number of fruits required to make a bushel. The average number 

 of fruits per bushel from the irrigated trees x/as 126 as compared to 170 

 fruits per bushel from the non-irrigated trees. It took 44 less apples from 

 the irrigated trees to fill a bushel. 



Table 1 shows approximately 91% of the fruits from the irrigated trees 

 were greater than 2 1/2 inches in diameter as compared to 54% from the non- 

 irrigated. By count, 206 apples from the 7 bushels graded from the irrigated 

 trees x^/ere 3 inches or greater in diameter. Only 8 three inch apples were 

 harvested from a similar volume of non- irrigated fruit. 



Table I - Percentage of Various Size Apples of the Fruit Sampled from Irrigated 



