236 MASS. EXPERIMENT STATION BULLETIN 280 



Mcintosh and Wealthy apple trees. Care was taken to have the trees on the 

 sev( ral plots of the same average size, though the individual trees showed some 

 differences owing to variation among the trees available. With one or two 

 e.xccptions the trees started and made good growth. The fertilizer treatment 

 on Plot 11 was changed to 8 pounds superphosphate, 53^ pounds muriate of 

 potash and 8 pounds nitrophoska and that of Plot 13 to 143-^ pounds superphos- 

 phate, 8 pounds muriate of potash and 12 pounds of tankage. The fertilizer 

 treatment of all other plots was continued as in previouus years. 



Role of Potash and Lime in Fruit Tree Nutrition. (J. K. Shaw). This 

 study by means of pot cultures was continued. The use of sulfur to acidify soil 

 from the potash -phosphorus-lime plot proved very injurious to the trees. Lower- 

 ing the pH value to 4.0 or less apparently prevented nitrification and nearly or 

 quite prevented growth of the seedling peach trees used as indicators. Alum- 

 inum sulfate used for the same purpose had little effect. Nitrogen carriers other 

 than nitrate of soda favored growth. These included ammonium sulfate, urea, 

 calurea, blood, fish, and cottonseed meal. Lime favored growth as in previous 

 years. 



Effect of Potash and Lime on Apple Trees. (J. K. Shaw). This project 

 is carried on in a sod orchard of Wealthy trees planted in 1915. It was planned 

 to throw light on several c^uestions that are of interest to fruit growers, the most 

 important of which were the value of the addition of potash and phosphorus to 

 nitrogen, and the value of lime as a supplement to the different mixtures used. 

 As the trees tend strongly to biennial bearing, some trees bearing heavily one 

 year and some the other, the yields must be considered in two-year periods. 



It was assumed that in this orchard nitrogen was necessary. The question 

 whether potash added to nitrogen increased the yield is not yet positively an- 

 swered. Half of the plots were limed and half were unlimed. The unlimed plots 

 averaged 8 per cent more than the limed plots in 1930-1931. The nitrogen plots 

 yielded about one-third more than the plots without nitrogen, while with the 

 1928-1929 crops the increase was about one-fifth. This suggests the probability 

 of increasing differences in later years. 



The potash and phosphorus plots yielded moderately heavy crops and there 

 is reason to believe that on this soil such a fertilizer is better than none. The 

 average plot yield per tree varied from 382 pounds to 855 pounds. It is evident 

 that factors other than fertilizer treatment are responsible for the larger differ- 

 ences in yield. 



Study of Varieties of Tree Fruits. (J. K. Shaw and O. C. Roberts). This 

 project has been broadened to include small fruits as well as tree fruits. It is 

 impossible to say with accuracy just what varieties are "new." We have the 

 follow'ing numbers of varieties which we consider may be called new: apples, 59; 

 peaches and nectarines, 33; pears, 5; plums, 11; cherries, 8; grapes, 20; black- 

 berries, 9; raspberries, 20; blueberries, 16; strawberries, 16. IMost of these 

 varieties will doubtless prove of no value, but among them are probably a very 

 few that will rise to considerable commercial in.portance. 



Among the new varieties of apples are about a dozen red-fruited variants 

 from well-known varieties. Some of these promise well; others are little better 

 than the older varieties. There are several distinct sports of Gravenstein among 

 which the one originating in Washington and distributed by the New York 

 Fruit Testing Association seems superior. Starking and Richared seem to be 

 more desirable than Delicious. It is not known that Gallia Beautv is a bud 



