ON THE GROWTH OF LEGUMINOUS CROPS. 5 



Wheat, Barley, or Roots, grown under the same manurial conditions, 

 that is without nitrogenous supply, but each grown continuously on 

 the same land ; whilst, in an exactly corresponding rotation, but with 

 fallow instead of a leguminous crop in the third year, the average 

 annual yield of nitrogen over the 32 years, was only 24*3 Ibs. 



It is seen, then, that the increased yield of nitrogen in the rotation- 

 crops, was largely due to the interpolation of the Leguminosce, the Clover 

 or the Beans ; in part owing directly to the large yields of nitrogen in 

 these crops themselves, but in part to the increased yields in the Wheat 

 immediately succeeding the Leguminous crop, which, especially the 

 Clover, would leave an effective nitrogenous crop-residue, but, in part 

 also, to some effect from this increased crop-residue on the other crops 

 of the course ; and lastly, to the fact, that the various crops grown in 

 alternation have different root ranges, and grow during different periods 

 of the season. The Wheat, in fact, yielded nearly as much after the 

 removal of the highly nitrogenous Leguminous crop, as on a corres- 

 ponding plot left Fallow ; from which, therefore, no nitrogen had been 

 removed in the produce in the preceding year. 



The next illustrations show more strikingly still, the greater yield 

 of nitrogen in Leguminous than in Gramineous crops, grown under 

 equal soil conditions. They relate to the yield of nitrogen in Barley 

 and in Clover, grown side by side in the same field ; and the results 

 are given in Table II. 



TABLE II. 



Nitrogen per acre per annum, in Barley and Clover, grown in Little Hoosfield, 



Rothamsted. 



The field had grown one crop of Wheat, one crop of Oats, and three 



crops of Barley in succession with artificial mineral and nitrogenous 



manures, but without any farm-yard or other organic manure. In 



11872, Barley was again sown; on one half alone, and on the other 



ihalf with Clover. In 1873, Barley was again grown on the one 



ij half, but the Clover on the other. The Table shows that the Barley 



j yielded 37'3 Ibs. of nitrogen per acre, whilst the three cuttings of 



\ Clover contained 151*3 Ibs. In the next year, 1874, Barley was grown 



I over both portions : and on the one where Barley had yielded 37'3 Ibs. 



of nitrogen in the previous year, it now yielded 39 - 1 Ibs. ; but on the 



portion where the Clover had yielded 15T3 Ibs., the Barley succeeding 



it yielded 69 -4 Ibs. That is to say, the Barley yielded 30 -3 Ibs. more 



