190 
On Breaking up Grass Lands. 
converted into arable will in a great measure be indicated by the 
succession of crops named in our estimates. But the nature of 
the soil of our island is almost as variable as the rocks on which it 
rests, and therefore the rotations which 1 have named can only 
be applicable to a limited extent. They cannot be strictly appli- 
cable to all soils, nor to the same soil in different circumstances. 
There are exceptions to all rotations arising; from situation, cli- 
mate, soil, population ; and, therefore, I dare not presume to 
offer them as applicable under all conditions. They are only 
indices of that system which may be successfully applied on 
soils having characteristics in common with those which we have 
mentioned. Even on the soils possessing those general charac- 
teristics, the crops may be very much varied from those which we 
have named. Thus it may occasionally be best to sow oats 
instead of barley, and beans and other green crops on a portion 
of the land which I have assigned for seeds, and many other 
changes may arise from circumstances, which will cause the farmer, 
indeed compel him, to deviate from those systems ; but if he 
adhere to the one grand point, of following the white crops with 
green crops, whatever system he may adopt will have nearly the 
same result as those proposed. 
On thin light calcareous or gravelly soils, sainfoin will answer 
better than seeds, and therefore should be substituted. The strong 
fibrous roots of sainfoin operate on the thin loose soils of cal- 
careous rocks, like the arundinacece on the sands on the sea-coast, 
in imparting cohesion to the soil. Sainfoin also produces by the 
time it is worn out a tough sward, full of vegetable matters, which 
by paring and burning furnish a large quantity of ashes, exceed- 
ingly useful to the succeeding turnip crop. It will therefore be 
desirable to sow sainfoin on all such lands, with the view of 
modifying the physical character of the soil, as well as to obtain 
manure for turnips, and a large quantity of feed from poor thin 
soils, sometimes exhibiting scarcely anything on the surface but 
the comminuted portions of ro(;k, on which, however, sainfoin 
flourishes and remains in vigour for years. Downs are prin- 
cipally confined to the chalk, and there sainfoin will often take 
the place of seeds after barley, lasting for five or six years. It 
arrives at perfection the second year, and begins to decline about 
the fifth, after which the brcaslplough is diligently used, and 
turnips succeed. In our estimates we have considered the green 
crop to be comprised in the term turnip crop, which is made up 
of tares or vetches on all the better kinds of light loams after 
wheat, which are the same season succeeded by turnips. On 
stiffer kinds of soils the green or fallow crops, which are to be 
partly consumed on the land, are composed of swedes, turnips, 
cabbages, mangold-wurzel, vetches, and white mustard ; and on 
