380 



ANNUAL REPORT OF THE 



Off. Doc. 



results from onr experiments show that it is by no means indispen- 

 sible in the production of first jjrade apples and that it can be 

 readily over-emj)hasize(l like anythinjij else. There are many situa- 

 tions that are otherwise very well suited for apples, where tillage 

 is decidedly inadvisable, and where, with proper management, the 

 trees would get along very much better without it. In such situa- 

 tions it is undoubtedly preferable to sow the orchard down to some 

 leguminous crop as a permanent cover and follow the mulch system, 

 properly supplementing it with fertilization. For this purpose;, 

 hairy vetch is doubtless preferable, on account of its relatively low 

 moisture draft, and its usually excellent staying powers when once 

 well seeded down. Whenever it is crowded out by the grasses, the 

 orchard may be re-plowed and again sowed to vetch, if the trees 

 seem to require it. 



DATA ON FERTILIZERS FROM OTHER EXPERIMENTS 



Thus far we have confined our attention to a single experiment, 

 primarily because the contrasts in it are so great that both the exist- 

 ence and nature of the effects could scarcely fail to be recognized. 

 To go through each experiment in this way would be impossible 

 in our present space, hence we have condensed into the next two 

 tables a statement derived from the results of six experiments, in- 

 cluding the one just discussed. These tables show the average ef- 

 fects of the difi'erent fertilizer elements, obtained in six experi- 

 ments, during periods covering from three to five years as indicated. 

 The efi'ects are calculated as closely as possible and are expressed 

 in terms of per cents, of benefit based on the normal performance 

 of the treated plots. The methods followed in making the calcu- 

 lations are described briefly in our Bulletin 100 from the Pennsyl- 

 vania Station, and described in full in our Annual Eeport for 1910- 

 11. 



TABLE V. EFFECT OF FERTILIZER ELEMENTS ON YIELD, COLOR, 



SIZE AND GROWTH 



(Calculated Percents of Benefit,) 



Experiments 336, 338 and 339. 



Yield. 



Color. ! Size, i Growth. 



1908-11. 



1911. 1909-11. 1909-11. 1908-11. 



Nitrates in combination, 



Phosphates in combination. 



Potash in combination, 



Complete fertilizer, 



Manure, 



Lime alone, 



PerCt. 

 94.05 

 36.65 

 —4.65 

 122.5 

 144.1 

 19.5 



Per Ct. 

 163.1 

 35.8 

 —6.42 

 166.4 

 169.8 

 —3.07 



Per Ct. 

 —13.3 

 —.95 

 —.1 



—16.0 



—14.3 



—2.9 



Per Ct. 

 —4.81 

 4.04 

 13.2 

 5.93 

 30.8 

 19.4 



PerCt. 



24.11 



—3.97 



4.17 



27.50 



37.49 



8.04 



