MANURING ORCHARDS. 155 



III. — The Yield with Barnyard Manure. 



Baskets 

 per acre. 



1884-1891, inclusive, 8 years, average per year .... 169.5 



1884-1893 " 10 " " " .... 194.7 



1887-1891 " (5 crop years) " " .... 271.3 



1887-1893 '• (7 crop years) " " .... 276.8 



IV. — The Eelative Yield in an Unfavorable Season. 



B.Tskets 

 per acre. 



1889 unmanured 10.9 



1889 fertilized 152.5 



1889 manured 162.5 



The first point of importance and value observed is in reference 

 to the number of crops that were secured. On the unmanured 

 land, the crops secured after eight yeai's were so small as to 

 materialh reduce the average for the whole period, while for the 

 manured land the average for the whole period was not only not 

 reduced, but very materially increased ; that is, the crops secured 

 on these after the trees on the unmanured land had practically 

 ceased to bear were greater proportionately than those secured 

 previous to that time. This was true both for the fertilized and 

 manured land. 



In the next place it is shown that the yield was very materially 

 increased by the use of manures, either in the form of artificial or 

 natural supplies, and the differences in yield derived from these 

 two forms are very slight, indicating that very much smaller 

 amounts of actual plant food in quick acting forms were quite as 

 useful as larger amounts of the less available forms in which the 

 food exists in natural manure products. 



For the ten years, the fertilized plot received 250 pounds of 

 nitrogen, 560 pounds of phosphoric acid, and 750 pounds of pot- 

 ash, while the yard manure plot received — assuming the average 

 composition of yard manure — 2,000 pounds of nitrogen, 2,000 

 pounds of phosphoric acid, and 1,600 pounds of potash; yet with 

 eight times as much nitrogen, nearl}^ four times as much phos- 

 phoric acid, and more than twice as much potash, the yield was 

 but 113 baskets greater, or 11 baskets per year. There was 

 no material difference in the size of the trees on the two plots ; 



