244 EXPERIMENT STATION EECOKD. [Vol.38 



amount of water inoreasiug as the season advanced to about two weeks before 

 picking' time gave apples of the best keeping qualities without sacrificing any 

 of the crispness so essential to good apples. 



"A dormant irrigation applied in the late fall just before the ground freezes 

 is very essential and beneficial in most of the irrigated fruit districts of Idaho. 

 From the time that the apples are picked until this time, tlie orchard si juld 

 be allowed to dry out in order that the wood of the trees may become thoroughly 

 ripened. The percentage of soil moisture in the late fall affects the percentage 

 during the entire winter and early spring following. If an orchard is given 

 this late dormant irrigation in the fall, the first irrigation the following spring 

 may be put off considerably later than if the orchard went into the winter in a 

 dry condition. This fall irrigation is very desirable. 



" On the sandy soil in the Payette Valley, in a full bearing orchard of Winesaps 

 and Jonathans with a clover cover crop, about 3 acre-feet of water per sea.sou 

 gave the maximum results considering yield, grade, color, size, keeping qualities 

 of the fruit, and the health of the tree. Here, also, the best results from the ap- 

 plication of water were obtained when most of it was applied during the period 

 of greatest apple growth." 



Besults from orchard fertilization {Pennsylvania Sta. Bui. 147 (1011), 

 pp. 3^-37, fly. 1). — This comprises a brief summary of the results secured during 

 the nine-year period from the orchard management experiments started by the 

 station in 1907 (B. S. R., 35, p. 540; 38, p. 42). 



The fertilizer experiments have shown in general that nitrogen is likely to be 

 of most importance in orchards for improving both yield and growth. Thus 

 far the nitrogen from commercial sources or from stable manure has proved 

 more effective than that from cover crops. When slow-acting carriers of 

 nitrogen are used no immediate effects should be expected before the following 

 year. As indicated by experiments conducted eLsewhere, applications of nitrate 

 of soda about the time the buds are starting into growth in the spring or 

 slightly later may materially influence the crop of the current season. 



Neither phosphorus nor lime when used alone has exerted any important 

 influence on either the yield or growth of apples in these experiments. The 

 addition of phosphorus to nitrogen, however, has generally proved very benefi- 

 cial. The gains from this combination in certain ca.ses have exceeded 200 bu. 

 per acre annually for the last nine years. It is pointed out that lime may be 

 indirectly beneficial at times through its favorable influence on the growth of 

 leguminous cover crops. 



The rate of application now recommended for an acre of bearing trees con- 

 sists of 150 to 200 lbs. of nitrate of soda and 250 to 300 lbs. of acid phosphate 

 or their equivalents. For younger trees which are less likely to respond to 

 fertilizers a good mulch of stable manure at the rate of 8 tons per acre is 

 recommended. Potash has proved of material benefit in only one experiment. 

 Fifty lbs. of the high grade muriate or its equivalent is now considered ample 

 for an acre of bearing trees. 



No fertilizer has materially improved the color of the fruit and those con- 

 taining nitrogen have generally reduced it. This is probably due to delayed 

 maturity, which has an advantage in the case of the more northern varieties, 

 such as Baldwin, Hubbardston, and Mcintosh, when grown in Pennsylvania. 

 Lack of color in these varieties is readily overcome by delaying the picking. 

 With varieties requiring a long growing season, such as the York Imperial, 

 it may be necessary to utilize other aids to color, such as open pruning and 

 sod culture, in order to overcome the detrimental effects of nitrogen. In cer- 

 tain orchards no kind of fertilization lias yet proved beneficial. 



