Report of Experiments on the Growth of Jflieat. 
479 
* 
during the earlier stages of growth, but of lato years the bulk 
has perceptibly declined, and the proportion of blighted ears 
has increased in a remarkable degree. Still, the average propor- 
tion of corn to straw is higher than in any case with equal or 
higher amounts of total produce per acre grown by artificial 
manure's. It will be remembered that it was on plots 0, 4, and 5, 
where, as on these plots 11, phosphoric acid was relatively very 
abundant, that the highest proportion of corn to straw in the 
series was obtained. On the other hand, excepting one or two 
other marked cases of defective manuring, the Aveight per bushel 
of the dressed corn of plots 11 was almost the lowest in the 
series. There was, therefore, with a full average tendency of 
growth for the production of a fair proportion of corn, at the 
same time very defective power of maturation. 
It has been seen how very ineffective were mineral manures 
either to bring into activity the unexhausted residue of previous 
nitrogenous manuring, or to give increase by inducing a greater 
accumulation of nitrogen by the plant from natural sources ; 
but the results of the series of experiments now under considera- 
tion clearly show, how very effective and lasting were the mineral 
manures employed, to meet the demands made upon the soil 
for mineral constituents by the use of the nitrogenous manures 
even in distant succeeding seasons. 
Average Annual Produce by Nitrate of Soda, used alone, or with 
the Mixed Mineral Manure. 
During the last 12 years plot 9b has been manured with 
nitrate of soda alone, at the rate of 475 lbs. per acre in the first, 
and of 550 lbs. in each of the 11 succeeding years. The latter 
amount was taken as equivalent in nitrogen to the 400 lbs. 
of ammonia- salts applied in so many of the other experiments ; 
but as of late years nitrate of soda of commerce has been purer 
than formerly, it was probably slightly more than equivalent in 
nitrogen to the mixture of 200 lbs. of muriate and 200 lbs. of 
sulphate of ammonia of commerce. During the preceding 8 
years 9 b was manured with ammonia-salts 7 times, once with 
rape-cake in addition, in the 1st and 5th seasons received 
superphosphate of lime, and in the 6th was unmanured. It 
was, in fact, at the commencement of the 12 years, in a con- 
dition intermediate between that of plots 10<z and 10Z> so far as 
the supply of mineral constituents was concerned ; and the effect 
of the nitrate will be best brought to view by comparing the 
results with those of these two plots manured with ammonia- 
salts. 
Whilst 400 lbs. of ammonia-salts alone, applied for 19 years 
on plot 10a, and for 13 years on plot 10b, gave an average 
2 L 2 
