26 



and the land was several times left fallow, during the 

 period. 



At the conclusion of the 32 years (in 1878), the land 

 was left fallow until September 1882, when it was sown 

 with grass-seeds, which, however, failed in the winter, and 

 then another Leguminous crop red clover which had 

 not been grown on the same land for very many years, 

 was sown (with barley), and it yielded, on this so to speak 

 bean-exhausted land, large crops ; which, within a period 

 of about 2 years, accumulated (including a little in the 

 barley) more than 300 Ibs. of nitrogen per acre in the 

 removed crops ; whilst, at the same time, the surface 

 soil became determinably richer in nitrogen. 



This result was obtained, where another Leguminous 

 crop had yielded smaller and smaller crops, where the 

 surface soil was very poor in total nitrogen, very poor 

 in nitrogenous crop residue for nitrification, and the 

 subsoil was, to a considerable depth (72 inches), very 

 poor in ready-formed nitric acid. Here, again, then, 

 satisfactory explanation as to the source of the nitrogen 

 of the crop fails, in defect of evidence as to whether, or 

 in what degree, the subsoil has contributed to the result. 

 In view, however, of recent results, showing the fixation 

 of free nitrogen as a coincident of the development of 

 the so-called " nodules " on the roots of leguminous 

 plants, there can be little doubt that at any rate some 

 of the nitrogen accumulated by the clover after the 

 beans in Geescroft Field, and also of that obtained by 

 the lucerne, and other leguminosse, grown after the 

 failure of red clover in Hoosfield, was due to the fixation 

 of free nitrogen under such conditions. See Nos. 81, 

 82, and 84, in the list. 



As in the case of other crops, samples of both bean- 

 corn and bean-straw, have been preserved. In all, the 

 dry matter and the ash have been determined ; and, in 

 the case of the produce of some plots in a number of 

 individual years, and of some in " mixed-year " samples, 

 the nitrogen has been determined. Complete analyses 

 have also been made of 34 corn and 34 straw ashes, 

 representing in each case " mixed - year " samples, 



