370 
Field Experiments on Root-Crops. 
Table sliowin<^ increase in Swedes of each IManm-ed Plot over the average 
produce of the Unnianured Plots, calculated per Acre and increase per 
Cent. :— 
Maxcre vsed. 
Increase. 
Mineral Superphosphate .. 
Mineral Superphosphate .. 
and 
Muriate of Potash 
Mineral Superphosphate .. 
and 
Guano 
Guano 
Mineral Superphosphate .. 
Muriate of Potash 
and 
Sulphate of Ammonia 
Rotten Dung (full dressing) 
Mineral Superphosphate 
Muriate of Potash 
and 
Nitrate of Soda 
Ivotten Dung (half dressing) 
and 
Mineral Superphosphate .. 
Bone Dust 
and 
Superphosphate 
Average produce of Un-V 
manured Plots per Acre . . J 
tons. cwts. lbs. 
4 8 38 
5 2 32 
10 
1 101 
15 67 
53 
IG 47 
19 59 
13 67 
Peruvian guano, it will be seen, gave the best results ; 3 cwts, — 
which is by no means a heavy manuring — beating, in its imme- 
diate effects upon the root-crop, 20 tons of rotten dung, andlpro- 
ducing an increase of 9 tons 1 cwt. 4 lbs. over" the average yield 
of the unmanured plots. 
Next in order to the guano follows the plots manured with a 
heavy dressing of rotten dung. The latter, it will be seen, pro- 
duced nearly 4 tons of tops, or 8^^ cwts. more tops than the 
Peruvian guano plot No. 5. An excess of organic matter, espe- 
cially if rich in nitrogenous and ammoniacal compounds, as is 
well known, favours too much the development of the tops, and 
prevents the swelling and proper maturity of the bulbs. 
I hardly expected the result which was obtained with 3 cwts. 
of guano, for a mixture of guano and superphosphate, generally 
speaking, answers better for root-crops than either applied 
separately. The land on which the experiments were tried 
was probably not in a high agricultural condition, which may 
account for the highly beneficial effect of guano upon the crop 
of swedes. 
