160 Report of Experiments on the Groioth of Barley, 
consideration of its indications in their bearings upon the coin^ 
cident stage and tendency of growth of the plant, if we would 
attain any really clear conception of the connection between the 
ever fluctuating characters of season, and the equally fluctuating 
characters of growth and produce. 
Comparison of the average Annual Produce of Barley over the 
first 10, the second 10, and tlie total period of 20 years. 
There is still another point in connection with the influence 
of season upon the crop, which should be considered before 
treating more exclusively of the effects of the different manures. 
Thus, before attempting to compare the effects of different ma- 
nures, used year after year on the same plot, it is obviously neces- 
sary to form a judgment whether the earlier or the later seasons 
of the series were, in themselves, the most favourable, so as to 
distinguish as far as possible between the results due, on the one 
hand to more or less favourable seasons, and on the other to 
the direct action of the manures, in maintaining a suitable 
balance of the required constituents in the soil, or in inducing 
exhaustion, or accumulation, as the case may be. 
In Table XXllI. there is given the average produce over the 
first ten, the second ten, and the total period of twenty years, by 
very different descriptions of manure, and a comparison of the 
results will illustrate the point in question. The plots selected 
are 5 out of the 7 quoted in the preceding Tables, namely — 
that manured with farmyard-manure every year ; the continuously 
unmanured plot ; the one with mixed mineral manure alone every 
year ; that with 200 lbs. ammonia-salts alone every year ; and that 
with both mixed mineral manure and 200 lbs. ammonia-salts every 
year. It is obvious that these five plots supply very various, and 
very opposite' soil-conditions, so that the comparative effects of 
the seasons on each must have considerable significance. 
In the first place, there is, with each of the five very opposite 
conditions of manuring, a considerably higher average weight per 
bushel of dressed corn over the second, than over the first ten 
years of the twenty ; and the superiority is the greatest with the 
highest manuring and the heaviest crops — namely, with farmyard- 
manure, and with ammonia-salts and mixed mineral manure to- 
gether. The proportion of corn to straw is also the higher over 
the last ten years, and the higher with the heavier crops. Further 
evidence that the later years were in the main more favourable 
than the earlier, at least for the production and maturation of 
grain, is to be found in the fact that there was also a less pro- 
portion of offal corn during the second half of the total period. 
With a considerable difference in the weight per bushel of the 
dressed corn, it is obvious that the comparative productiveness 
