73 



indicated here in amounts per bearing tree instead of per acre as 

 above and the same reductions should be made for younger trees. 

 In other words, if only a third of the ground is to be covered, then 

 only about a third of these amounts should be used, if the rate of 

 application is to be kept within proper bounds. 



These general precautions, together with the exercise of proper 

 judgment on the part of the grower, are entirely sufficient to carry 

 this plan to a successful conclusion and definitely settle the ferti- 

 lizer needs of any ordinary orchard within a few years. If addi- 

 tional rules and precautions are desired, however, they can be 

 found in the Annual Report of the Pennsylvania State College for 

 1910-11, pages 409-11. In addition, it should be remembered that 

 an orchard may not show the need of a fertilizer when young, but 

 may develop this need later, especially when heavy bearing is 

 reached. This means that the cases that appear negative at any 

 one time often need further tests and attention later. 



Discussion. 



E. C. Tyson. Would the result in the Brown experiment in- 

 dicate that phosphoric acid might be eliminated from the applica- 

 tions ? 



Dr. Stewart. No, it does not. It simply means that you are 

 not likely to get the benefit from an application of phosphoric acid 

 alone that you would when applied along with some other material, 

 unless you should happen to have an abundance of all other neces- 

 sary elements. Then you might get it by applying phosphoric acid 

 alone. 



Mr. Bassett. Is that in Pennsylvania, Professor? 



Dr. Stewart. It was in one part of Pennsylvania. The soil 

 in this particular case had been cropped heavily for a long time and 

 was very much exhausted. I might say for Pennsylvania soils, 

 however, that we have averaged about thirty bushels of wheat to 

 the acre for the past twenty years on the College Farm that is run 

 in connection with the Experiment Station, which will probably 

 compare favorably with similar averages in any other state. 



Mr. Bassett. I was afraid you were slurring the state, that 

 was all. 



Dr. Stewart. There is a difference in the way even good soil 

 may be handled. Notice, however, that even in this soil, the best 

 trees in the orchard are the ones planted in the old sod pasture 

 with a spade. No cultivation before planting nor since. One 

 hundred pounds of straw to the tree were used as a mulch for the 

 first two years. Since that time the growth between the trees has 

 been sufficient to maintain a mulch. These trees that were just 

 planted in sod were not permitted to have grass growing over the 

 roots, however, and that is the thing we must emphasize. Grass 

 growing over tree roots is objectionable and is bound to stunt the 

 trees. Where we have grass growing over tree roots we usually 



