Effects of Manures on Grass-Land. 
131 
when priced at guano rates, since those rates give to farmyard- 
manure a value of 135. per ton, it remains for the farmer who 
does not set so high a figure even on his good bullock-manure, 
to make ^ deduction accordingly, so as to reconcile the valuation 
with the prices of the times. 
IX. — On the Effects of different 3Tannres on the Mixed Herbage 
of Grass-land. By J. B. Lawes, F.R.S., F.C.S., and J. H. 
Gilbert, Ph. D., F.R.S., F.C.S. 
In Vol. XIX., Part II., and Vol. XX., Parts I. and II. of this 
Journal, we gave a Report on Experiments with different manures 
on permanent meadow land, in which we treated of the subject 
under the following heads : — 
Part I. The produce of hay, per acre. 
Part 11. The produce of constituents, per acre. 
Part III. The description of plants developed by different 
manures. 
Part IV. The chemical composition of the hay. 
Perhaps the most striking points brought out in the inquiry, 
were those which illustrated the very great difference in the 
description and character of the plants developed by the different 
manv;res. The general results arrived at under this head, may 
be very briefly re-stated here. 
The unmanured crops, and the light ones grown by manure, 
were by far the most complex in character ; consisting of a com- 
paratively large number of species of plants, or descriptions of 
herbage, and showing less predominance of a few species than 
did the more bulky produce obtained by means of more active 
manures. The smaller crops consisted not onlv of a greater 
variety of Graminaceous herbage, or grasses properly so called, 
but also contained a greater variety and greater proportion of 
miscellaneous or weedy herbage. 
As a rule, whatever the description of manure employed, any 
considerable increase of crop was accompanied bv greater sim-^ 
plicity of herbage, greater predominance of grasses proper, and 
also, generally, a greater predominance of individual species, 
both among the Graminaceous or grassy, the Leguminous, and 
the miscellaneous herbage. 
-■-4 • 
But different descriptions of manure had very different effects. 
Mineral manures alone (salts of potass, soda, magnesia, and 
superphosphate of lime) only moderately increased the amount 
of crop ; rather diminished the proportion of the grasses, and 
K 2 
