FERTILIZERS AND MANURES FOR THE ORCHARD 199 



however, the addition of phosphorus has resulted in no im- 

 portant benefit." Also, "Potash has increased the yields 

 materially in three of the experiments in bearing orchards 

 and apparently has shown some value in increasing the size 

 of the fruit. It has also apparently had an injurious effect 

 in two of the eight experiments. It would seem advisable 

 therefore, to defer its general use in any particular orchard 

 until definite evidence of its value. is secured." Manure 

 has usually had a beneficial effect, although it is slower 

 acting than nitrate of soda. These conclusions are supported 

 by the following data: 



Table LXI 



10-year summary of results in fertilizing apple orchards in 



pennsylvania. yield to the acre in bushels (after stewart) 



The kind and amounts of fertilizer commonly used in the 

 Pennsylvania experiments are shown in table on page 200. 



