Field Experiments on Root-Crops. 
371 
On cold soils, and in tlie northern parts of England, Peruvian 
guano, 1 have noticed, is frequently used for root-crops with 
greater advantage than on very free-growing land, or in the 
south of England. 
On looking at the preceding tabulated results, it will be seen 
that muriate of potash has been of considerable service to the 
swede crop, and that the further addition of either nitrate of 
soda or sulphate of ammonia to a mixture composed of mineral 
superphosphate and muriate of potash, proved very beneficial to 
that crop. 
The mixture containing nitrate of soda had slightly the advan- 
tage over the compound of superphosphate, muriate of potash, 
and sulphate of ammonia ; but the difference in the weight of 
plots No. 7 and No. 9 is too small to be noticed, and the result 
obtained on these two plots certainly does not indicate the 
superiority of nitrate of soda over sulphate of ammonia in the 
mineral manure. 
The least effective of all the manures used in these expe- 
riments was the mixture of 3 cwts. of bone-dust and 1^ cwt. of 
superphosphate ; for this mixture actually gave rather a smaller 
increase than 3 cwts. of superphosphate alone. 
On the whole we may learn from these experiments that 
compound artificial manures containing readily available phos- 
phates, salts of potash, and a fair amount of nitrogen, either in 
the shape of ammonia, or in the form of nitric acid, were more 
serviceable to the swede crop than purely mineral superphos- 
phate ; that such compound manuring matters largely increase 
the produce, and that they may be used with economy by root- 
growers. 
Experiments on Sivedes made, in 1869, at Tuhney Warren, 
Abingdon, by Mr. James Kimber. 
The same manuring scheme which was adopted in the 
preceding experiments was carried out by Mr. Kimber, who, 
however, left only two, instead of three plots, unmanured. 
One of the main objects I had in view in all the experiments 
in 1869 was to ascertain under what circumstances potash-salts 
might be usefully employed as manuring agents for root-crops, 
and this I sought to attain by trying precisely the same manuring 
matters in various localities and soils. 
The field on which Mr. Kimber's experiments were tried, he 
informs me, had been down Avith sainfoin five years previous to 
1868. It was then broken up, and in 1868 grew a crop of 
wheat, manured with a moderate dressing of Peruvian guano. 
The various manures used for the experiments upon swedes 
were sown broadcast, and the land afterwards ploughed. The 
