206 



FUNDAMENTALS OF FRUIT PRODUCTION 



increase was obtained. Gourley^^ found substantially the same general 

 condition in his experimental plots in New Hampshire — particularly 

 during the early years of the experimental treatments. Table 68 

 assembled from data presented by him and some of his associates,^ 

 recapitulating the first 5-years' results, explains some of the preceding 

 statements that at first appear more or less conflicting. This table 

 shows practically no increased vegetative growth accompanying the 

 use of fertilizers, as compared with plots under clean cultivation or plots 

 growing annual cover crops, even though one of the fertilizers contained 



Table 68. 



-Response in Vegetative Growth from Fertilizer Applications 



{After Gourleif^) 



relatively large amounts of nitrogen. However, soil cultivation, 

 particularly when coupled with cover crops, made available to the 

 plants an abundant supply of nitrogen — a supply that obviously was 

 present in the sod land, but unavailable. This abundant supply met 

 the trees' nutritive requirements and the surplus resulting from appli- 

 cations of nitrate did not effect any consistently increased growth. 

 In a report on the same series of experiments 5 years later Gourley^" 

 states that though there was no special or marked increase in yield in 

 the fertihzed plots over those not receiving fertihzer "the orchard is 

 developing in that direction." In other words, the period of maximum 

 production without applications of nitrogenous fertilizers had been 

 reached. This period might last for a number of years, or be of short 

 duration; in either case greater and greater increases in vegetative 

 growth and fruit production could be expected from proper fertiliza- 

 tion. As trees increase in age and size they require larger amounts of 



