a 

 3r- 

 us 

 he 

 wn 

 an 

 er 

 er 

 fro- 



a 



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55 



herbage plots can leave little doubt that the increased yield of nitro- 

 gen in the more highly leguminous produce of the mineral-manured 

 plot had its source in the stores of the soil itself. 



Source of the Nitrogen of Glover Grown on Rich Garden Soil. 



We have one more illustration to bring forward having an import- 

 ant bearing on the question of the sources of the nitrogen of the 

 Leguminosee. 



In view of the signal failure in the attempts to grow red clover on 

 a nitrogen exhausted arable soil, it is of much interest that large, 

 though declining, crops have been grown for twenty-nine years in 

 succession on a small plot of rich kitchen- garden soil. 



The experiment was commenced in 1854, and the following table 

 shows the percentage of nitrogen in samples of the first 9 inches of 

 soil, taken in October 1857, and in IMay 1879 ; that is, with an 

 interval of twenty-one seasons of growth. In 1857 only one sample 

 was taken, and only to the depth of 9 inches ; but in 1879 three 

 samples were taken, in each case to the depth of twice 9, or 18 inches. 

 The results given in the table relate to the first 9 inches of depth 

 only : — 



Table XVIII. — Clover Grown on Kitchen Garden Soil. 

 Nitrogen, per cent, in dry Mould, and per Acre. 



The percentage of nitrogen given for the single sample collected in 

 October 1857, is the mean of determinations made in 1857, 1866, and 



* In the original paper, too high an average weight of soil per acre was adopted, 

 and hence the amounts of nitrogen per acre were estimated to be higher than now 

 given ; but the difference was only 9 pounds more (139) than according to the 

 new calculation. 



i;'W 



