Experiments on the Growth of Wheat. 
211 
wealth of the soil is more than sufficient for the annual atmo- 
spheric supply of available nitrogen. And the object of sowing 
one plot with ammoniacal salts in the autumn and another in the 
spring, was to show whether it was practically advantageous to 
sow such soluble manures in the autumn in so light a soil. 
The mixture of botli tlie minerals and the ammoniacal salts 
shows, when the results are compared with those of each of these 
manures used separately — 1st, whether or not the annually avail- 
able native mineral supply of the soil, taken together with that 
in the manure, was not competent to a much greater amount of 
growth than the annual atmospheric supply of nitrogen was suffi- 
cient to produce ? — and 2ndly, whether tlie amount of nitrogen 
supplied to the soil, when such a quantity of ammoniacal salts 
was used alone, was not in excess in proportion to the annually 
available supply of minerals from the soil itself? 
Rape-cake contains a large proportion of carbonaceous and 
nitrogenous organic substances, and some mineral matter ; and 
the nitrogen which was supplied in the quantity of it used was 
nearly identically the same, or perhaps rather greater in amount, 
than that in the ammoniacal salts of the other experiments. 
The farm-yard dung employed, was the product of yards in 
which bullocks were fed on turnips, with a moderate quantity of 
oilcake. In this farm-yard dung, there would be added to the 
soil every year a larger supply of every constituent than was 
contained in the increased wheat crop grown. 
In the three following Tables are given, the quantities of the 
different ingredients used as manure, and also the results obtained. 
In Table I. are given — The amounts per acre each year on 
each plot, of the dressed corn, the offal corn, and the straw.* 
In Table II. are given — The total produce of corn for the four 
years collectively, and of the straw for the last three years, of each 
plot ; the average annual produce, both including and excluding 
the first year of the experiment ; the total increase by manure of 
corn in the four years, and of straw in three years ; the average 
annual increase by manure ; and in the last column, the amount 
of corn yielded by each plot in the first year (1851) above the 
average of the succeeding years. 
In Table III. are given — The weight per bushel of the dressed 
corn of each plot each year, and the average of the four years ; 
also the proportion of offal corn to 100 dressed corn in each case ; 
and the proportion of corn to 100 parts of straw. 
* It is much to be regretted that the straw was only weighed in the three last 
years, and that in no case is the weight of chaff and " cokler " or " cavings " 
given. 
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