I 
400 The Propagaiioix and Prevention of Smui 
to be affected. Secondly, while it may be quite true that faiTii* 
yard manure when applied to fields causes the crop to have 
more smut in it than is the case in unmanured fields, yet this 
arises from the manure increasing the fertility of the land, and 
not from the introduction of smut spores. Nor does it matter 
in what way the fertility is increased, whether by farmyard or 
by artificial manure, or by the system of cropping, the result 
is the same. 
That this is true the following facts show : — 
(a) In the plot, which we may call the Permanent Barley Plot, previously 
referred to, there was one portion which was heavily treated with farmyard 
manure annually for more than JjSyears. It is true that this portion had a con- 
siderahly larger percentage of smutted ears than those other portions of the 
same plot where the crop was poorer, from the soil either being unmanured, 
or treated with artificial manure from which some essential of plant-food was 
excluded (nitrogen, phosphates, or potash). But the first-mentioned portion 
of the plot (that treated with farmyard manure) was not more heavily 
smutted than the other plot on which barley had been grown every fourth 
year for the same period of 25 years, and which had never had during all 
that time any farmyard manure at all upon it, but which, owing to the good 
system of cropping adopted, produced very good and strong barley. 
(b) At the side of the portion of the Permanent Barley Plot which was 
treated with farmyard manure there was a portion which had annually 
received a compound artificial manure in which aU the necessary constituents 
of plant life were present. Both these portions produced a good crop, 
although that manured with farmyard manure was a little more luxuriant. 
1S55 1886 
In the farmyard-manured portion . 42 smutted eara 1*2 per cent. smut. 
In the artificially maniu-ed portion . 35 „ I'O „ 
So that really the proportion of smut was very nearly the same in both cases, 
and what trifling difference there may have been may fairly be attributed to 
the difference in the fertility of the two portions. 
It is well known to farmers in all countries that as long 
as the seed-wheat has been properly dressed with sulphate of 
copper, there is no need for them to fear bunt, inasmuch as it is 
almost impossible to find a single bunted ear in these fields, 
whether they have been manured with farmyard or artificial 
manure. From this fact alone we must conclude that the 
dunghill plays a very insignificant part in the dissemination of 
bunt in wheat. 
III. Spores of smut adhering externally to the seed of 
barley and oats are unable, to any appreciable degree, to 
infect the crop produced from that seed. It is a well-known 
fact that when the spores of bunt (7'. iritici) are sown ad- 
lieriiig to the seed-wheat the crop is certain to be more or less 
bunted, and if many spores adhere to the wheat almost every 
plant will be diseased. 
I 
