218 BOARD OF AGRICULTURE. 



This crop of hay would be made up of elements taken from the 



air and from water, 11,775 



Elements taken from the soil, including nitrogen, 225 



12,000 



The Deficient plant food, or that which must be attended to by the 

 farmer, amounts to one hundred and thirty-nine pounds, made up 

 as follows : nitrogen, forty-five pounds; phosphoric acid, seventeen 

 pounds, potash, seventy-seven pounds. 



It is necessary to provide for all of the nitrogen, phosphoric acid 

 and potash, or will the soil furnish a part of these? 



It is a well-known fact, that all soils fit for tillage are capable of 

 producing small crops continuously. Old fields will produce in the 

 vicinity of half a ton per acre of the so-called '"June grass," or 

 "white-top," year after year. Such a crop takes from the soil plant 

 food, and when once the crop has reached the lowest limit in its 

 yield and continues year after year practically the same, the plant 

 food contained in this minimum crop represents the natural capacity 

 of that particular soil to provide nifrogen, phosphoric acid and 

 potaish. Just what this natural eapacit}' amounts to may be illus- 

 trated hy comparatively definite figures. Lawes and Gilbert, in their 

 famous English experiments, have raised wheat for forty years con- 

 tinuoush' on their plots, and some have received absolutel}^ no 

 manure \n all this time. The following figures show the natural 

 capacity of their soil. 



Bufh. 



Wheat average for 40 years, no manure, 14 



'• 32 " '' 13J 



" " 7 " '' 15^ 



" " 3 •' '• 18 



Ik '' 4 " '' 25f 



The first two cases are on the same field, the others represent 

 results on different parts of their estate. The average yield of 

 straw for thirty-years was 1,125 pounds 



Taking the experiment plots on our Experiment Station farm and 

 I find that in 1885 we produced on the plots having no manure 47^ 

 bushels sound corn, weighing 40 pounds per bushel ; 27| bushels soft 

 corn, weighing 34 pounds per bushel ; and 3,246 pounds of well 

 cured fodder. The yield of oats on the same land was 33^ bushels, 

 and 1 ,900 pounds of straw, and the past year the yield of haj' was 



