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♦ 
V. — Report of Experiments on the Growth of Wheat for 20 Years 
in succession on the same Land. By J. B. Lawes, F.R.S., 
F.C.S., and J. H. Gilbert, Ph. D., F.R.S., F.C.S. 
The records of a field of 14 acres in which wheat has been 
grown without manure, and by different descriptions of manure, 
year after year for twenty successive seasons, without either 
fallow or a fallow crop, and in which the lowest produce 
was in the first year 15, and in the last 17£ bushels, and the 
highest in the first year 24J, and in the last bushels, cannot 
fail to be of much interest at once to the practical farmer, to the 
economist, and to the man of science. Accounts there have 
been before, of the growth of wheat for many consecutive years 
apparently with great success, and without much evidence of 
exhaustion, on soils of admittedly extraordinary fertility ; and 
the recent experience of the Rev. S. Smith, of Lois Weedon, 
has shown that, on his soil at least, many wheat-crops can be 
taken, under a system of alternate crop and fallow, without 
reaching, at any rate for many years, the point of deterioration. 
History also tells us of large tracts of land on which the wheat- 
crop has been cultivated year after year for many years, but 
which have eventually succumbed to the unnatural strain put 
upon them. The records to be laid before the reader in the 
present paper refer to conditions of growth like in some points, 
but essentially different in most, to those of the cases to which 
allusion is here made. 
The experiments have been made upon what may be called 
fair average wheat-land. But, as the rental of similar land in 
the immediate locality ranges, and has ranged for many years 
past, only from 25s. to 30s. per acre, tithe free, and its wheat- 
crop under the ordinary management of the district certainly 
does not average more than from 25 to 27 bushels per acre 
once every five years, it is obvious that, in a practical point 
of view, it can lay no claim to extraordinary fertility, or to be 
ranked on a higher level than a large proportion of the soils on 
which wheat is grown with a moderate degree of success under 
a system of rotation and home manuring. Such, in an agri- 
cultural or commercial point of view, were the general charac- 
ters of the land. Speaking still in agricultural language, it may 
be said that the soil is a somewhat heavy loam, with a subsoil 
of raw yellowish red clay, but resting in its turn upon chalk, 
which provides good natural drainage. 
The questions arise : — What are the grain-yielding capa- 
bilities of such land ? — what its powers of endurance ? — in what 
constituents, or class of constituents, does it soonest show signs 
