-1/2 180
1278 ... 191
1283 8-1/2 ...
1284 10-1/2 ...
1285 7-1/4 ...
1300 (7-10) ...
1340 5-1/2 126
1341 7-1/2 138
1342 6 132
1344 ... 129
1346 5-1/2 127
1347 6-1/2 128
1348 6-3/4 138
1349 4-3/4 128
1350 5-1/4 ...
1351 6-1/2 ...
1352 8-1/2 ...
1353 5 ...
1397 6-1/4 51-1/2

The yield of the soil in single seasons at widely separated intervals
is a piece of information of little value for our purpose. These
tables reveal other facts of greater significance. The yield for the
year gives almost no information about the normal yield over a series
of years, but the area planted depends very largely upon that yield.
The farmer knows that it will pay, on the average, to sow a certain
number of acres, and the area under cultivation is not subject to
violent fluctuations, as is the crop reaped. The area sown in any
season is representative of the period; the crop reaped may or may
not be representative. Land which, over a series of years, fails to
produce enough to pay for cultivation is no longer planted. If the
fertility of the soil is declining, this is shown by the gradual
withdrawal from cultivation of the less productive land, as it is
realized that it produces so little that it no longer pays to till it.
Table IV shows that in fact this withdrawal of worn out land from
cultivation was actually taking place. The area sown with wheat on the
twenty-five manors for which the statistics for both periods are
available was reduced by more than fifty per cent between the
beginning and the end of the thirteenth century. A similar reduction
in the area planted with all of the other crops, mancorn, rye, barley
and oats, took place. A process of selection was going on which
eliminated the less fertile land from cultivation. If s