26 J. H. Gilbert — Points in connection with Vegetation. 



together with that condensed within the pores of the soil from 

 the atmosphere, be derived from previous accumulations within 

 the soil, so also may the excess of yield by the so-called "root- 

 crops" be accounted for. 



We now come to the consideration of the yield of nitrogen 

 when plants of the leguminous family are separately grown, or 

 when they, and plants of some other families, are grown in 

 alternation, or in association, with the Graminese. Table Ifl 

 shows the results obtained with beans, and with clover ; with 

 clover and barley grown in alternation; and with turnips, 

 barley, clover or beans, and wheat, grown in an actual course 



„„...,. 



— —- 



2L 



£'-:;Zm 



Beans -l 



— | 



Barley 

 Clover 



Barley 

 Rotation 



Unmanured i 



12 yrs. 1847-'58 

 12 yrs. 1859-'70(») 

 24 yrs. 1847-'70 



12yrs.'l859-'70(*) 



22 yrs. 1849-'70(t) 

 22 yrs. 1849-'70(f) 



1 yr. 1873 



1 yr. 1874 



368 



6 1 



Unmanured 







> i 



u — i - S£ 



Barley after Clover more than after ) 



1 3 Clover or Beans \ 1 Superphos- 

 U Wheat J [ phate.... 



Referring first to the results obtainec 

 shows that without manure then 



— #ith beans the table 

 that without manure there was an annual yield over thefirst 

 e years, 1847-1858, of 481 lbs. of nitrogen. Over the 

 twelve years, 1859-1870, it was reduced to 14-6 lbs. per 

 per annum. Still, over the whole period of twenty-four 

 we have an annual yield of 81 '8 lbs., or more than c" 

 half time as much as in either wheat or barlev. 

 ine years Beans, one year Wheat, two years fallow, 

 i years Clover, one year Wheat, three years Barley, twelve years fallo' 



