STATE POMOLOGICAL SOCIETY. I09 



These results are naturally much more complicated than those 

 in the recently planted orchards considered above. The differ- 

 ences also are less distinct and much less uniform in their trend 

 in many cases, and the relative values of the several treatments 

 are more variable in the different soils and localities. Part of 

 this variability is doubtless connected with the natural unsteadi- 

 ness, in yield especially, that is generally characteristic of trees 

 in their early stages of bearing. The extent and importance of 

 the latter influence, however, can only be determined by fur- 

 ther results and perhaps by additional experiments. 



But notwithstanding the present difficulties, a few points are 

 fairly clear. In the first place, it may be noted that the sod 

 treatment has uniformly resulted in the poorest growth and 

 the best color of any of the treatments. This is doubtless 

 chiefly due to its usual accelerating influence on maturity. On 

 yield thus far, sod has usually exerted a stimulating influence, 

 a fact which is especially noticeable when it occurs in connec- 

 tion with manure. The exceptionally high average in this sod 

 manure treatment, however, can be traced primarily to the un- 

 usual yields in Experiment 217, as in the other two experiments 

 it is a notable fact that four out of six of the other treatments 

 with manure are against this average. The same is true of the 

 sod average obtained in the series without fertilization, as 

 shown in Table V. 



The present yield benefits from sod, moreover, are evidently 

 being secured primarily as a result of mild injury, as is shown 

 by the fact that the sod trees are making the least growth of 

 any of the treatments, and in the series receiving commercial 

 fertilizer they are also showing the lowest average yield. Grass 

 sod growing over tree roots, therefore, must generally be con- 

 sidered as an objectionable treatment. 



THE CROP VALUE OF A MULCH. 



In terms of fruit, it will be noted in Table V that our annual 

 mulch applications alone have given an average increase of 

 about 35 bushels of apples in two of the experiments, and have 

 resulted in no gain over sod in the third. These differences 

 might be greater if the trees were larger and in another experi- 

 ment on older trees, as shown in Tables IX and XII, it will be 

 observed that the mulch has given a maximum annual gain of 



