67 





TO *? 





0 6 



0 AC 



■^•45 



Potash in Combin., 





2.7 



5.8 



3.67 





78.3 



15.4 



5.2 



17.67 





75-9 



II. 4 



5.8 



29.07 





8.24 



0.3 



2.0 



6.31 



(b) Expts. 336, 338 and 339 



1908-'! 2 



I909-*I2 



i909-'i2 



1908-'! 2 





74.5 



12.7 



0.4 



27.00 



Phosphates in Combin., 



33-5 



2.8 



4-9 



0.23 





3.6 



1.4 



7.1 



2.79 





80.5 



15.6 



5.2 



29.63 





168.8 



15.9 



25.2 



37.34 





29.8 



5-4 



15.9 



15.48 



Without going into details it may be noted that in general the 

 same influences that have materially increased the yields have also 

 increased the growth. In other v^ords, our best growing plots have 

 as a rule been our best fruiting plots. On sound, healthy trees, this 

 will generally be the case unless either occurs to an abnormal ex- 

 tent, in which case the other may be somewhat reduced. Mild .in- 

 juries may also stimulate yields at the expense of growth. 



In Table V, the most marked exception to our rule above ap- 

 pears in the case of the phosphates, especially in the lower section 

 of the table. This may be connected with the fact that the old wood 

 especially is very low in phosphoric acid, as shown in Table I, and 

 our present definite growth determinations are based upon increase 

 in trunk-girths alone. On twig-growth, however, our observations 

 indicate that phosphate additions have been very helpful, particular- 

 ly in the Brown orchard. This also tends to bring it in line with our 

 rule above. 



The Control of Average Size. — So far as fertilization is con- 

 cerned, manure and potash are the only materials that have consist- 

 ently benefited size. The manure influence is doubtless very largely 

 due to its mulching or moisture conserving efifect, since moisture 

 makes up about 84.6% of this fruit, on the average.* The potash 

 influence also, so far as it is a definite benefit, is probably brought 

 about through the same medium, inasmuch as potash is credited 

 with some ability to increase the cosmotic power of the cells, thus 

 enabling them to compete more successfully for whatever water is 

 present. 



There is also a distinct possibility that the apparent benefit 

 of potash on any size may be largely due to the fact that it is as- 

 sociated with much lower yields than the other materials, especially 

 nitrogen. Conversely their failures to increase size may likewise 

 be due to their association with markedly increased yields. 



This brings out the general proposition to which we have called 

 definite attention elsewhere,t that with a normal moisture supply 



♦See Table XVIII in the writer's article in the Annual Report of the Penn- 

 sylvania State College for 1910-11, page 435. 

 tSee article referred to in foot note 2, pages 500-503. 



