Report of Experiments on the Growth of Wheat. 
409 
results over the last 12 years, from each description of manure 
applied year after year on the same plot, during the whole of 
that period. These are given in Table XXX., pp.470, and 471. 
The details of the manures are given in Appendix Table IX., 
and are further explained in the Notes at p. 163, facing that 
Table. The details of the produce of each separate plot in each 
separate year will be found in Appendix Tables X. — XXVI., 
pp. 164-185. 
It may be explained tlfat in the Summary Table XXX., 
wherever the plots are divided into two (a and b), and both por- 
tions are manured alike, giving duplicate experiments and results, 
the mean of the two only is given. 
Average Annual Produce icithout Manure. 
There were three plots entirely unmanured during the last 
12 years of the experiments to which the results in Table XXX. 
refer. Plot 3, had been unmanured for the 8 preceding years 
also, as well as during the 5 years of rotation before the experi- 
ments commenced. Plot 20, which was at the other side of the 
field, had been unmanured the same number of years as plot 3, 
with the exception that in the third year it received a mixture of 
the surplus of the artificial manures used on the other plots. Plot 4 
had been unmanured during the last 12 years only ; during the 
preceding 7 years it had been manured with large quantities of 
superphosphate of lime and sulphate of ammonia, and in the first 
year of the 20 was manured with the ashes of farmyard manure. 
Plot 3, which had grown wheat without manure for the whole 
20 years, and plot 20 for 19 out of the 20, gave almost identical 
average annual amounts of produce over the last 12 years. On 
almost every point, however, plot 20 gave slightly the better 
result ; but the difference is so small that the experiments mutually 
confirm each other, and the produce of plot 3 (continuously un- 
manured) is adopted as the standard by which to compare that 
of the manured plots. 
Its average annual yield per acre over the 12 years was 15-J- 
bushels of dressed corn, and 1662 lbs. or nearly 15 cwts. of straw. 
The average weight per bushel of the dressed corn was lower than 
in any case but two of the manured produce ; but the proportion 
of corn to straw was almost exactly the same as with farmyard 
manure, and higher than in most cases with artificial manure. 
The tendency to produce a fair proportion of corn to straw was, 
therefore, without manure, more than equal to that under the 
majority of the conditions with manure ; and the low weight per 
bushel was, doubtless, due to the sluggish growth and consequent 
defective power of ripening. 
Plot 4) 
