Farminfj of Cornwall. 
423 
soiling is exceedingly beneficial in retentive clayey soils having a 
porous stratum beneath, for by breaking through the clayey bed 
the excess of moisture rapidly sinks, and the land is then ren- 
dered dry and healthy. On the granite, too, where drainage is 
not required, or has been successfully done, subsoil-ploughing is 
very successful. Its mode of action consists, in this case, of bring- 
ing up portions of the decom])osed felspar (7) in the form of 
clay, which becomes mixed with the peat, the union producing 
an ameliorating influence on the "grovvan" soil. The application 
of the clay from the decomposed slate very considerably improves 
the growan soils, and again, the mixing of the decomposed fel- 
spar of the granite is found to be a valuable addition to the slate 
soils. 
General Culture. 
36. The crops most generally cultivated are wheat, barley, 
oats, hay, turnips, potatoes, and vetches ; within the last tweniy 
years, rape, cabbage, mangold, and carrots have been partially 
introduced on a great many of the best managed farms. 
37. iVlieat. — The process of preparing the land for this grain 
varies in the different parts of the county. When not pre- 
ceded by a green crop, the grass-land is "ploughed to rot," or 
of a clayey, shelly slate, the upper half had so little soil upon it that its 
general character was "poor" — thin and dry — witli scarcely enough earth 
to cover a ploughshare. (See analysis of this description of subsoils 
(72) containing lime and potash.) Early in the spring of 1841 the half 
of this field was ploughed to a depth of 7 inches with a strong iron 
plough, and afterwards worked, manured, and cropped the same as the 
other portion of the field, by potatoes and mangold, crossing it at right 
angles, and the crop was nearly as good upon the upper half as the 
lower, where the soil was originally deep. In 1842 the tield was sown to 
barley, and it proved a uniform crop, and not the least affected by the 
summer drought, as was previously the case. In 1843, and at the present 
time, it is grass, and a fair crop all over. 
Experiment 2. — A piece of dry land of sevei'al acres, of a similar 
character to the last, lying on a sparry, clayey soil, was broken from grass 
in 1841, the worst part subsoiled, and the whole sown to turnips. The 
crop was an average one on the field generally ; one-half was consumed 
by folding sheep on every alternate row, and the following year sown to 
spiing wheat. In the winters of 1842 and 1843 the whole field was sub- 
soiled right across the former subsoiling. In 1843 it was put into potatoes 
and mangold, both being a good crop, and beyond any expectation, con- 
sidering the previous state of the ground — the benefit evidently being 
attributable to the subsoiling. About 200 cart-loads of spar stones were 
raised and removed in this operation, much of which was so near the sur- 
face as to intercept the ploughing even at 3 inches deep. 
Experiment 3. On the Growan Soil. — A portion of a field situated in a 
hollow, genei-ally wet with the water standing on the surface in the winter, 
having a crust, or " moorland pan," that prevented its escape. This was 
broken by the subsoil plough in 1841. The crop on this part of the field 
was equal to the dry portion, which was never the case before. In 1843 
a fair crop of oats was taken, and the grass is at the present period ex- 
eeedingly good, and the water has never lodged there since. 
