212 On Permanent and Temporary Meadows and Pastures. 
This arises from the accumulation of organic debris on the 
surface of the soil. In the case of temporary grass-lands, the 
dressing with lime can be dispensed with where the soil con- 
tains more than 5 per cent, of lime. And as the ley only lasts 
two or three years, there is no fear of its getting sour, for the 
plough effects the mixture of the superficial with the lower 
layers of the soil. 
Lastly, on land which by analysis contains more than '30 per 
cent, ol magnesia and '10 per cent, of phosphoric acid, the 
magnesia may be reduced, or even dispensed with, and the 
assimilable phosphate of lime in the manure may be replaced 
by fossil phosphate, which appreciably diminishes the cost. 
The dressing of lime should be applied in the autumn, im- 
mediately after the last mowing. The chemical manures should 
be applied in early spring, before vegetation makes its new 
start. 
Farmyard-manure* — I cannot conclude this article without 
alluding to the comparatively small utility of farmyard-manure 
for maintaining grass-lands. We have seen that grass-lands 
require but little nitrogen, but that they ought to have it in the 
most assimilable form, because it must act promptly, especially 
at the starting of the annual vegetation. To obtain the maxi- 
mum advantage from this nitrogen, I have said that it ought ta 
be applied in the form of nitrogen salts ; now, farmyard-manure 
contains a large amount of nitrogen, but very little in a soluble 
state, and none in the nitric state, unless indeed it is in an 
advanced state of decomposition. 
The nitrogenous matters in farmyard-manure only furnish 
assimilable nitrogen slowly and in small quantities, and the 
work of transformation only proceeds when the manure is 
mixed with a soil easily permeable by air and moisture. 
The application of farmyard-manure as a top-dressing tO' 
grass-lands, is not favourable for the promotion of the necessary 
chemical transformations. It should be applied in large quan- 
tities and in a very advanced state of decomposition, in order 
to obtain from it an appreciable effect ; further, it owes its effect 
more to the potash and other mineral elements which it con- 
tains, than to its nitrogen, which, by this mode of application, 
is almost wasted. 
Moreover, to supply the necessary potash by means of farmyard- 
manure, which only gives it up very slowly, for every ton of dry 
hay about 5 tons of well-rotted farmyard-manure are necessary ; 
that is to say, about 13"49 tons per acre for the production of 
• M. Joulie's views on the suitability of farmyard-manure as an economical 
dressing for grass-land do not agree with those of Dr. Voelcker. Vide ' Journ. 
Eoyal Agiic. See' Second Scries, vol, xiv. p. 836. — Edit. 
