^ield Experiments on Root-Crops. 
385 
artificials. Altliougli very heavy dressings of manure may do 
no harm to so greedy a feeder as the mangold-crop, it is very 
questionable whether it is good policy in average seasons to put 
as much as half a ton of suj)erphosphate, or guano, or more, on 
mangolds. It appeared to me desirable, moreover, to ascertain, 
by actual experiments, whether or not the application of very 
large quantities of various kinds of artificial manures may not 
injure the crop. I therefore suggested to JNIr. Brown to apply as 
much as 16^ lbs. of superphosphate or guano, kainite, &c., to a 
plot of -rrnrtl^ of an acre, which amounts to about 15 cvvts. of each 
kind of manure per acre. 
The plots, ten in number, each — uT)^^ acre, were treated 
as follows as regards manure : — 
Xo. 1. Left immannred. 
2. Eeceived ICi lbs. dissolved Coprolites. 
3. „ IGi „ dissolved Coprolites and 16J lbs. of Kainite. 
4. „ I62 „ Kainite. 
5. Was left iinmannved. 
6. Was dressed -with I62 lbs. rcriivian Guano. 
7. „ „ with IGj „ dissolved Coprolites, 16j Kainite. 
and I62 „ Peruvian Guano. 
8. „ „ with 1 load of fresh Horse-dung. 
9. „ „ with I load of fresh Horse-dung and I63 lbs. 
dissolved Coprolites. 
10. Was left unnianured. 
The crop on plots Nos. 1 and 2 showed no difference in appear- 
ance. On plot No. 0 the mangold looked more healthy and luxu- 
riant, during the whole of the summer, than on plots Nos. 1 and 2. 
Plot No. 4 appeared about equal with plot No. 3. 
On plot No. 6 (manured with guano) the mangolds were larger 
than on plots Nos. 4 and 5. 
Plot No. 7, as far as could be judged by its appearance, was 
the best of the lot. 
The plants on plots Nos. 8 and 9 were very slow in starting, 
which was probably due to the manure being taken fresh from a 
horse-yard. 
The produce of each plot was carefully weighed, and the 
results given in the next Table were obtained. 
The average weight of mangolds from the unmanured plots 
was 18 tons 15 cwts, 7 stones 2 lbs. 
The preceding experiments show — 
1. That dissolved coprolites, applied alone, had no great effect 
upon the produce. 
2. That kainite alone increased the crop considerably. 
3. That, in combination with dissolved coprolites, kainite pro- 
duced a more favourable result than kainite applied by itself. 
4. That the largest increase in the crop was obtained by the 
mixture of dissolved coprolites, kainite, and guano. 
