372 Report of Experiments on the Growth of Barley, 
together. We further stated our conviction, founded on a very 
extensive acquaintance with the practical experience of farmers 
in the use of artificial manures in every district of Great Britain 
for many years, that, in 99 cases out of 100 in which wheat is 
grown in the ordinary course of agriculture with rotation, the 
supply of immediately available mineral constituents is in excess 
relatively to the immediately available supply of nitrogen. 
In our former paper on the growth of Barley, and again in 
Section V. of the present paper, evidence of a similar kind is 
adduced in regard to that crop. Two sets of experiments are 
quoted. In one, barley was grown for three years in succession 
on a series of plots which had previously been differently ma- 
nured, and grown ten crops of turnips in succession. In the 
other, it was grown in four-course rotation, without manure, and 
- with different descriptions of manure. The evidence of these 
other experiments is entirely confirmatory of the conclusion, 
that mineral manures alone will not yield fair crops of barley, 
and that an essential condition for the growth of full crops, 
whether in rotation or under less usual conditions, is a liberal 
supply of available nitrogen within the soil. 
Further, as in the case of wheat, so also in that of barley, the 
common experience of the country at large, in the use of artificial 
manures to that crop, is entirely confirmatory of the conclusions 
to which the results of the experiments on its growth year after 
year on the same land would lead. 
It may here be remarked, that the greater liability to loss by 
drainage of the nitrogen, than of the more important mineral 
constituents of manure, is doubtless one element in the explana- 
tion of the fact of the prevailing excess of available mineral 
constituents, relatively to available nitrogen, in soils generally, 
under the ordinary course of agriculture in this country. 
Those who have examined for themselves the evidence that has 
been adduced, and carefully considered the conclusions that have 
been drawn in reference to the great number of points which the 
enquiry has opened up, will probably feel that they do not require 
any specific receipts to be laid down for their guidance, and that 
they will profit more by the direction which the study of the 
facts must give, to their own observation and reflections on what 
comes before them in the course of their daily experience. 
Indeed, under any circumstances, it must be left to the intelli- 
gence and the judgment of the individual farmer to decide upon 
the degree in which any special recommendations will be appli- 
cable to his own particular soil, and other circumstances. 
Still, in bringing this long report to a conclusion, a few words 
should be offered by way of pointing out the more directly 
practical application of the results. 
