Feb., 1927] PROGRESS OF AGRICULTURAL EXPERIMENTS 23 



Pruning Experiment with Apples — {Hatch Fund) 



Data are presented in Table X on the pruning and the growth of 

 Spy and Mcintosh trees at tlie close of their seventh season under 

 different systems of pruning. Data are also included on the amount 

 of pruning done in the spring of the eighth season. 



Unfortunately in this experiment all the trees under a given treat- 

 ment are jilanted in the same block; hence differences in growth cannot 

 be ascribed wholly to the differences in pruning treatment. The unpruned 

 trees are smallest in this instance, due in all probability wholly to 

 unfavorable soil in the portion of the orchard in which they are planted. 

 In similar experiments elsewhere the unpruned trees have usually made 

 greater total growth than those pruned. During the season of 1925 the 

 gains in trunk diameter were in proportion to the previous growth of 

 the trees, those plots wliich were largest at the outset making great- 

 est gains during the season. In all instances, considering the condi- 

 tions, the differences in growth are too small to be ascribed to the 

 pruning. 



Fertility in the Peach Orchard — (Hatch Fund) 



The crop of peaches harvested in 1926 was only fair. Data on 

 yield and growth as affected by different fertilizer treatments are given 

 in Table XI. 



It is evident that factors other than the different fertilizer treatments 

 are responsible for differences between the plots. For instance, there 

 would ai)i)ear to be no logical reason why a tree fertilized with nitrate 

 of soda and acid phosjihate should yield less and make a smaller 

 growth than a tree fertilized with nitrate of soda alone. An effort has, 

 therefore, been made to arrive at averages which will have greater 

 significance than the results in any one plot. 



It is apparent that the use of nitrogen has resulted in an increased 

 growth and yield, although in this case it is necessary to compare the 

 plots receiving nitrogen with a single plot. No. 3, the only one which 

 does not receive this fertilizer. It may be said, however, that the 

 division rows which separate the plots and which do not receive nitro- 

 gen, are in all cases visibly smaller than the trees on either side which 

 do receive it. This is true in spite of the fact that the trees in the 

 division rows must gain some benefit from the fertilizer applied to the 

 rows on either side. 



In 1925 those trees which received nitrogen with pdtash had a greater 

 yield than those receiving nitrogen without potash. It was stated, 

 however, at that time that the difference was scarcely sufficient to be 

 considered significant. It may be noted in the data for 1926 that the 

 potash-treated trees show no greater growth or yield. 



Because Plots 1 and 2, which receive no phosphorus, are believed to 

 be better situated than Plots 4 and 5, it is not possible to draw any 

 conclusion as to the effect of this element. 



The only satisfactory evidence, therefore, is as to the value of nitro- 

 gen in the peach plantation. 



