The Conservation of Farm-yard Manure. 
837 
the third place, leaving well behind it the dung that received 
no special treatment for its preservation. A comparison of the 
results of the two sets of experiments seems, then, to confirm 
the previously expressed views of Holdefleiss on the choice that 
should be made in the treatment of the manui’e according to the 
nature of the soil to which it is to be applied. 
“ It need scarcely be said that we have no wish to lay down 
absolute rules on the subject, but it appears to be useful to bring to 
the knowledge of the farmer the facts that are brought to light in 
so methodically conceived a study of farm-yard manure as that made 
by the Director of the Institute of Proskau. It is for each one, 
having regard to his own local circumstances, to draw from these 
data the directions best adapted to the nature of his farming.” 
M. Grandeau having thus dwelt on the losses arising from the 
bad treatment of farm-yard manure, and on the best modes of meeting 
them, passes on to a consideration of the reasons which render farm- 
yard manure, even when properly made and kept, insufficient, in 
itself, to maintain the fertility of the land. 
The agricultural area of France is 48,000,000 hectares, of which 
rather more than one-half, viz., 24,340,000 hectares (roughly, 
60.000. 000 English acres), is given up to ordinary agriculture, i.e., 
to cereal crops, forage crops, and “ industrial ” crops. If the 
165.000. 000 tons per annum of (fresh) dung estimated to be produced 
by the live stock of France were spread equally over this area, the 
available quantity would lie only about 2| tons of dung per acre per 
annum. But such an application is far from being realised. There 
is, from a variety of causes, such as those already dealt with, an 
enormous waste in the production, storage, and application of this 
dung ; in addition to which consideration it is to be borne in mind 
that, over and above these 60,000,000 acres under ordinary farm 
cultivation, there is an immense area of market-gardens and vine- 
yards, which absorb a considerable quantity of manure. Correcting 
the estimate of manure available for actual farm use in the light of 
these considerations, the probable application is not more than 
about 2 tons per acre per annum. In a three-course rotation, if the 
manure were applied once in three years instead of annually, the 
average dressing, thus estimated, would be only 6 tons per acre 
triennially — a quantity, as M. Grandeau justly observes, altogether 
insufficient to raise satisfactory crops. 
“ It follows that it is absolutely necessary to have recourse to 
commercial fertilisers, nitrogenous or phosphatic, as a complement 
to the dung. But the insufficiency of dung is not confined to its 
mere quantity ; by bad management there is a loss of 14 to 24 per 
cent, of the fertilising value of the already too small quantity of dung 
which can be distributed on the land.” 
Having, in the course of his essay, clearly indicated the 
' simple means by which these losses may be minimised, M. Grandeau 
ends by vigorously urging the necessity of making them widely 
known, and of persuading landowners and farmers that the construc- 
tion of liquid-manure tanks, and the observance of such simple and 
