LEGUMINOUS CHOPS. 105 



further found that the above- and under-ground vegetable 

 residue picked from the clover-land samples was much more 

 in quantity, and contained much more nitrogen, than that 

 from the barley-land samples. 



In 1874, and in 1875, barley only was sown over both por- Further 

 tions. In 1876, barley was again sown over the whole of the s ™$j% 

 land, with clover as well on the portions where it had 

 grown in 1873 ; but the plant failed in the winter, and gave 

 no crop in 1877. In 1877, barley was again sown over the 

 whole ; this time with clover on half of the previously clover 

 portion, and on half of the previously only barley portion. 

 In the autumn of 1877 soil-samples were again taken ; this 

 time from four places on each of the differently cropped 

 portions. The determinations of nitrogen in the surface-soils 

 consistently showed, as before, a higher percentage where 

 clover than where only barley had grown. 



It is, of course, well known in agriculture, that the growth mtrogen^ 

 of clover, which removes much more nitrogen than a cereal in ^gumm- 

 crop, increases the produce of a succeeding cereal as if nitro- gramineous 

 genous manure had been applied. But attention is specially cro i> s - 

 to be directed to the fact, that a leguminous crop accumulates 

 a great deal more nitrogen over a given area than a gramin- 

 eous one under equal soil-conditions. 



But not only is the yield of nitrogen per acre much less in 

 the cereal crops, but the percentage of nitrogen in the dry 

 substance of the gramineous produce is much less than in 

 that of the leguminous produce. 



The corn of the leguminous crops — beans and peas, for 

 example — contains more than twice as high a percentage of 

 nitrogen in its dry substance as that of the gramineous grains. 

 The dry substance of leguminous straws also contains about 

 twice as high a percentage of nitrogen as that of cereal 

 straws. Again, the dry substance of clover-hay contains not 

 far short of twice as much nitrogen as that of meadow-hay. 

 Lastly, the dry substance of roots contains about the same 

 percentage of nitrogen as that of the cereal grains, but only 

 about half as much as that of the leguminous corn. The 

 leaves of the root-crops are, however, high in nitrogen. 



The general result is, then, that the wow-leguminous crops, 

 especially those of the gramineous family, are characterised, 

 both by yielding much less nitrogen in their produce over a 

 given area, and by containing a much lower percentage of 

 nitrogen in their dry substance, than the leguminous crops. 

 Bearing these facts in mind, let us now turn to the consider- 

 ation of the effects of direct nitrogenous manures on the 

 various crops. 



