198 



POMOLOGY 



Table LX — Continued. 



Row 

 No. 



Grass-mulch plot 



Nitrate of soda, 5 lbs. on tree circle 



Nitrate of soda, 5 lbs. on tree square 



No fertilizer 



Nitrate of soda, 5 lbs. ; acid phosphate, 5 lbs. on tree 

 circle 



Nitrate of soda, 5 lbs. ; acid phosphate, 5 lbs. on tree 

 square 



No fertilizer 



Nitrate of soda, 5 lbs.; acid phosphate, 5 lbs.; muri- 

 ate of potash, 5 lbs. on tree circle 



Nitrate of soda, 5 lbs. ; acid phosphate, 5 lbs. ; muri- 

 ate of potash, 5 lbs. on tree square 



Totals for grass-mulch plot 22,970 . 3 



5-year 

 average 

 1914-18 



Lbs. 

 2,817.9 

 2,295.5 

 1,503.7 



3,799.7 



3,641.3 

 1,773.5 



3,287.6 



3,851.1 



171. The Pennsylvania experiments ^ confirm the above 

 results in general, with some modifications. Again nitro- 

 gen has proved the most important element in increas- 

 ing the growth and yield of apple trees in sod, although the 

 other elements have seemed to be of greater importance 

 here than in the Ohio work. In a summary statement Stew- 

 art says, "The addition of phosphorus or potassium to ni- 

 trogen applications has usually given larger returns than 

 nitrogen alone. The nitrogen and phosphorus combina- 

 tion has produced an average increase over the normal yields 

 in two experiments of 265 and 308 bushels per acre amiually 

 during 9- and 10-year periods. This combination is also 

 proving important in one of the experiments in young or- 

 chards. In at least three of the other bearing orchards. 



Loc. cit. 



