20 



UNIV. OF N. H. AGR. EXPERIMENT STATION 



[Bulletin 221 



present condition of the trees. Some have already dedined until un- 

 profitable, and others give promise of good productivity for a considerable 

 period of years. 



Seven years' records of yield and growth have been accumulated since 

 the last report was issued on this experiment. Under ordinary circum- 

 stances a publication would have been issued at the end of the fifth year. 

 However, during the seasons of 1922-1923, the crop was reduced to 

 practically nothing, owing to the fruit buds being eaten from the trees in 

 winter by ruffed grouse which were driven to this unusual food owing to 

 deep snows and lack of food in the woods. 



The average yield in pounds per tree, average twig growth, and aver- 

 age trunk diameter are shown in Table IX. It will be noted that yield in 

 the sod plot is relatively low, the vitality of the trees in the sod plot having 

 been materially reduced ; and at present there are only eight trees remain- 

 ing which are considered to be in normal health. 



Table IX — Influence of culture on yield and growth of apple trees 



Plot 



1 

 2 



3 



4 

 5 

 6 



7 

 8 



9 



10 



Treatment 



years. 



Sod.. . 



Cultivation alternate 



Cover crop 



Cultivation alternate years. 



Cover crop 



Clean cultivation. No cover 



crop 



Clean cultivation plus cover 



crop 



Cultivation and cover crop 



plus complete fertilizer. 



(Phosphorus as basic slag) 

 Cultivation and cover crop 



plus complete fertilizer. . . 

 Cultivation and cover crop 



plus complete fertilizer 



with extra phosphorus . . . 

 Cultivation and cover crop 



plus complete fertilizer 



with extra nitrogen 



Cultivation and cover crop 



plus complete fertilizer 



with extra potash 



Average yield 



pounds per tree, 



1919-1925 



84.7±10.6 

 106.0±8.7 

 149.8±18.7 

 25o.6±21.4 

 255.4±11.9 



292.8±17.9 

 269.0±10.8 



282.6±14.8 



356.3±12.9 



270.8±19.0 



Average annual 



twig growth, 



1919-1924 



(Inches) 



7.32 

 4.75 

 7.96 

 7.63 

 7.38 



7.63 

 7.07 



7.57 



8.89 



8.00 



Average trunk 



diameter, 1924 



(Inches) 



12.3 

 13.4 

 14.3 

 14.1 



14.6 



14.8 

 15.0 



15.6 



15.7 



16.0 



•As a consequence, the determination of average yield in this plot and 

 also in Plots 2 and 3, which are cultivated only every second yesn', is not 

 an accurate one, the probable error being high in relation to average jdeld. 

 Cultivation has had a marked effect in maintaining vigor and increasing 

 the yield of the trees, cultivation every second year having produced a 

 yield intermediate between that received from trees standing continuously 

 in sod and that received from trees which are cultivated every year. 

 The annual yield of about 250 pounds per tree on the cultivated trees 

 only fair. A yield of two barrels of packed fruit per tree per year 



IS 



