On the Groicth of Barley hy different Manures, ^-c. 527 



supply of nitroo;en beyond that which in the average of seasons 

 can yield a well-conditioned and healthily ripened crop. Barley 

 indeed, from its comparatively limited hold on the soil, and its 

 small and weakly straw in proportion to the weight of corn it has 

 to cany, is, so far as favourable ripening and good sample are 

 concerned, more sensitive to vicissitudes of season and to high 

 manuring than wheat. And it is with the greater variation in 

 degree of maturation in the former than in the latter, in one and 

 the same season with different proportions of available nitrogen 

 provided within the soil, that we have at the same time, a greater 

 variation in the percentage of nitrogen in the produce depending on 

 the manure employed. 



Upon the whole it may be considered that, the percentages of 

 nitrogen in our produce of barley grown without nitrogenous 

 manure, were, for the soil and season in question, lower than 

 they would be in the ordinary practice of farming, owing to a 

 constant relative defect of nitrogenous supply for that amount of 

 crop, Avhich the soil and seasons were otherwise competent to 

 bring to a practically sufficient degree of perfection. On the 

 other hand, the figures in the Tables, taken together with the 

 circumstances of growth and the characters of the produce to 

 which they refer, would lead to the belief that, on the average of 

 seasons, the percentage of nitrogen can be but little increased 

 beyond the perhaps abnormally low amount obtained where the 

 nitrogenous supply was obviously in defect, without at the same 

 time a diminution in the practically admitted characters of high 

 quality of the corn. In fact, it would appear probable, that we 

 cannot, keeping within the limit of healthily matured full crops, 

 increase the percentage of nitrogen in our barley grain much 

 above a comparatively low amount, as our seasons go. Yet, the 

 fact that in 1857, which was an unusually favourable season for 

 the proportion and the ripening of the corn, we had a high per- 

 centage of nitrogen in the dry substance of that corn, supplies us 

 for barley (as was found in the case of wheat*), with an interest- 

 ing exception to any too wide an application of that which may 

 nevertheless be taken as a general tendency, at least within the 

 limits of our own locality and average climatic conditions. 



It is owing to the great influence of vicissitudes of season upon 

 the condition of the crop when harvested, that the percentages of 

 dry matter in the produce, and especially of the straw, of our 

 experimentally grown barley, have not the obvious connection 

 with the other points of composition of the crop that we should 

 otherwise have expected. Adequately to discuss these variations 

 in the percentage of dry matter, due to season and manuring, 



* See Quarterly Journal of the Chemical Society, before referred to. 



