ANNUAL REPORT, 1929 367 



tinue to yield more heavily, but it will be interesting to see what happens 

 if the white clover spreads over the entire area of the plot. 



Test of Different Amounts of Nitrate of Soda. (J. K. Shaw,). This 

 test on thirty-year-old Baldwins in sod has continued as in the past. No 

 injury to the trees has yet resulted from the use of twenty-five pounds 

 of nitrate of soda per tree- Owing- to the small number of trees in- 

 volved in this experiment, a considerable number of years will be re- 

 quired before it is safe to draw any conclu.sions. 



Comparison of Cultivation and Heavy Mulching for Apples and Pears. 



(J. K. Shaw). This experiment has been continued as in previous years. 

 The mulched trees continue to yield heavier crops and no injurious effects 

 of the large amount of nitrates in the soil under the mulch have been 

 observed. There seems to be a heavier drop from the trees on the mulch 

 plot just before harvesting, but this is not very serious as the apples 

 are little damaged and may be sold for good prices. It is felt that the 

 system of mulching trees with enough hay or straw to suppress the 

 growth of grass around the trees has possibilities in Massachusetts or- 

 charding. 



The Effects of Fertilizer Limitation on Fruit Plants. (J. K. Shaw). 

 This project has been continued as in previous years and nothing new 

 has appeared during the past s^son. Owing to the fact that the trees, 

 now seven years old, must have sent their roots beyond the boundaries 

 of the plots which are only ten feet wide, it is planned to remove these 

 trees and reset the area with other trees on uniform roots. While the 

 differences between plots have been marked^ there are also very great 

 differences between individual trees on the same plot. 



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



study of the soils on the orchards referred to in the previous paragraph 

 by means of experiments carried out in Wagner pots, has been continued. 

 Soil from the field plots was placed in the pots after various fertilizer 

 chemicals had been mixed in the soil. The general question of whether 

 the beneficial effects of potash and lime observed in the field were genuine 

 has again been answered in the affirmative, although not quite as em- 

 phatically as last year. 



Addition of nitrate of soda to soil from the potash plots failed to in- 

 crease growth as much as lime; therefore, it seems that the increase of 

 soil nitrates in plots receiving lime cannot be the sole cause of improved 

 growth. It is planned to continue this study next year. 



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

 is carried out in an orchard planted in 1915 and involves comparisons 

 of nitrate of soda, potash, superphosphate, and lime, alone and in various 

 combinations. Certain plots are fertilized so as to establish a sod of 

 white clover. This has been successful in many cases and seems to have 

 been beneficial to the trees. Still the trees receiving nitrogen have yielded 

 better than those without, although the difference is not great. No 

 superiority of color of apples from plots receiving complete fertilizer over 

 those from plots receiving nitrogen alone has been observed. In general 

 there is a tendency for plots receiving nitrogen to be inferior in color to 

 those neceiving no nitrogen from fertilizers. Observation in this orchard 



