an essential condition of such practice. This system of
free sale, indeed, frequently involves full compensation by
purchased manures of some kind. Such deviations from the
practice of merely selling grain and meat off the farm have
much extended in recent years, and will probably continue to
do so under the altered conditions of British agriculture,
determined by very large imports of grain, increasing imports
of meat and of other products of stock-feeding, and very
large imports of cattle-food and other agricultural produce.
More attention is thus being devoted to dairy produce, not
only on grass farms, but on those that are mainly arable.
The benefits that accrue from the practice of rotation are well
illustrated in the results obtained from the investigations at
Rothamsted into the simple four-course system, which may fairly
be regarded as a self-supporting system. Reference may first
be made to the important mineral constituents of different
crops of the four-course rotation. Of phosphoric acid, the
cereal crops take up as much as, or more than, any other crops
of the rotation, excepting clover; and the greater portion
thus taken up is lost to the farm in the saleable product--the
grain. The remainder, that in the straw, as well as that in
the roots and the leguminous crops, is supposed to be retained
on the farm, excepting the small amount exported in meat and
milk. Of potash, each of the rotation crops takes up very
much more than of phosphoric acid. But much less potash than
phosphoric acid is exported in the cereal grains, much more
being retained in the straw, whilst the other products of
the rotation--the root and leguminous crops--which are also
supposed to be retained on the farm, contain very much more
potash than the cereals, and comparatively little of it is
exported in meat and milk. Thus the whole of the crops of
rotation take up very much more of potash than of phosphoric
acid, whilst probably even less of it is ultimately lost to the
land. Of lime, very little is taken up by the cereal
crops, and by the root-crops much less than of potash; more
by the leguminous than by the other crops, and, by the clover
especially, sometimes much more than by all the other crops
of the rotation put together. Very little of the lime of
the crops, however, goes off in the saleable products of
the farm in the case of the self-supporting rotation under
consideration. Although, therefore, different, and sometimes
very large, amounts of these typical mineral constituents
are taken up by the various crops of rotation, there is no
material export of any in the saleable products, excepting
of phosphoric acid and of potash; and, so far at least
as phosphoric acid is concerned, experience has shown that
it may be advantageously supplied in purchased manures.
Of nitrogen, the cereal crops take up and retain much less
than any of the crops alternated with them, notwithstanding
the circumstance that the cereals are very characteristically
benefited by nitrogenous manures. The root-crops, indeed, may
contain two or more times as much nitrogen as either of the
cereals, and the leguminous crops, especially the clover, much
more than the root-crops. The greater part of the nitrogen
of the cereals is, however, sold off the farm; but perhaps
not more than 10 or 15% of the of either the root-crop of
the clover (or other forage leguminous crop) is sold off in
the animal increase of in milk. Most of the nitrogen is the
straw of the cereals, and a very large proportion of that of
the much more highly nitrogen-yielding crops, returns to the
land as manure, for the benefit of future cereals and other
crops. As to the source of the nitrogren of the root-crops--the
so-called ``restorative crops''--these are as dependent as any
crop that is grown on available nitrogen within the soil, which
is generally supplied by the direct application of nitrogenous
manures, natural or artificial. Under such conditions of
supply, however, the root-crops, gross feeders as they are,
and distributing a very large extent of fibrous feeding root
within the soil, avail themselves of a much larger quantity of
the nitrogen supplied than the cereal crops would do in similar
circumstances. This result is partly due to their period
of accumulation of nitrates in it is the greatest. When a
full supply of both mineral constituents and nitrogen is at
command, these root-crops assimilate a very large amount of
TABLE XI.--The Weight and Average Composition of Ordinary Crops,
in lb. per Acre.
Weight of
Crop. Total Nitro Sul-
Crop. At Pure -gen. phur. Potash.
Harvest. Dry. Ash.
Wheat, grain, 30 bushels 1,800 1530 30 34 2.7 9.3
Wheat, straw 3,158 2653 142 16 5.1 19.5
Total crop 4,958 4183 172 50 7.8 28.8
Barley, grain, 40 bushels 2,080 1747 46 35 2.9 9.8
Barley, straw 2,447 2080 111 14 3.2 25.9
Total crop 4,527 3827 157 49 6.1 35.7
Oats, grain, 45 bushels 1,890 1625 51 34 3.2 9.1
Oats, straw 2,835 2353 140 18 4.8 37.0
Total crop 4,725 3978 191 52 8.0 46.1
Maize, grain, 30 bushels 1,680 1500 22 28 1.8 6.5
Maize, stalks, &c. 2,208 1877 99 15 .. 29.8
Total crop 3,888 3377 121 43 .. 36.3
Meadow hay, 1 1/2 ton 3,360 2822 203 49 5.7 50.9
Red Clover hay, 2 tons 4,480 3763 258 98 9.4 83.4
Beans, grain, 30 bushels 1,920 1613 58 78 4.4 24.3
Beans, straw 2,240 1848 99 29 4.9 42.8
Total crop 4,160 3461 157 107 9.3 67.1
Turnip, root, 17 tons 38,080 3126 218 61 15.2 108.6
Turnip, leaf 11,424 1531 146 49 5.7 40.2
Total crop 49,504 4657 346 110 20.9 148.8
Swedes, root, 14 tons 31,360 3349 163 70 14.6 63.3
Swedes, leaf 4,704 706 75 28 3.2 16.4
Total crop 36,064 4055 238 98 17.8(*) 79.7
Mangels, root, 22 tons 49,280 5914 426 98 4.9 222.8
Mangels, leaf 18,233 1654 254 51 9.1 77.9
Total crop 67,513 7568 680 149 14.0 300.7
Potatoes, tubers, 6 tons 13,440 3360 127 46 2.7 76.5
Mag- Phosph- Chlor-
Crop. Soda. Lime. nesia. ric Acid. ine. Silica.
Wheat, grain, 30 bushels 0.6 1.0 3.6 14.2 0.1 0.6
Wheat, straw 2.0 8.2 3.5 6.9 2.4 96.3
Total crop 2.6 9.2 7.1 21.1 2.5 96.9
Barley, grain, 40 bushels 1.1 1.2 4.0 16.0 0.5 11.8
Barley, straw 3.9 8.0 2.9 4.7 3.6 56.8
Total crop 5.0 9.2 6.9 20.7 4.1 68.6
Oats, grain, 45 bushels 0.8 1.8 3.6 13.0 0.5 19.9
Oats, straw 4.6 9.8 5.1 6.4 6.1 65.4
Total crop 5.4 11.6 8.7 19.4 6.6 85.3
Maize, grain, 30 bushels 0.2 0.5 3.4 10.0 0.2 0.5
Maize, stalks, &c. .. .. .. 8.0 .. ..
Total crop .. .. .. 18.0 .. ..
Meadow hay, 1 1/2 ton 9.2 32.1 14.4 12.3 14.6 56.9
Red Clover hay, 2 tons 5.1 90.1 28.2 22.9 9.8 7.0
Beans, grain, 30 bushels 0.6 2.9 4.2 22.8 1.1 0.4
Beans, straw 1.7 26.3 5.7 6.3 4.3 6.9
Total crop 2.3 29.2 9.9 29.1 5.4 7.3
Turnip, root, 17 tons 17.0 25.5 5.7 22.4 10.9 2.6
Turnip, leaf 7.5 48.5 3.8 10.7 11.2 5.1
Total crop 24.5 74.0 9.5 33.1 22.1 7.7
Swedes, root, 14 tons 22.8 19.7 6.8 16.9 6.8 3.1
Swedes, leaf 9.2 22.7 2.4 4.8 8.3 3.6
Total crop 32.0 42.4 9.2 21.7 15.1 6.7
Mangels, root, 22 tons 69.4 15.9 18.3 36.4 42.5 8.7
Mangels, leaf 49.3 27.0 24.2 16.5 40.6 9.2
Total crop 118.7 42.9 42.5 52.9 83.1 17.9
Potatoes, tubers, 6 tons 3.8 3.4 6.3 21.5 4.4 2.6
(*) Calculated from a single analysis only.
carbon from the atmosphere, and produce, besides nitrogenous
food materials, a very large amount of the carbohydrate sugar,
as respiratory and fat-forming food for the live stock of the
farm. The still more highly nitrogenous leguminous crops,
although not characteristically benefited by nitrogenous
manures, nevertheless contribute much more nitrogen to the
total produce of the rotation than any of the other crops
comprised in it. It is the leguminous fodder crops--especially
clover, which has a much more extended period of growth,
and much wider range of collection within the soil and
subsoil, than any of the other crops of the rotation--that
yield in their produce the largest amount of nitrogen per
acre. Much of this is, doubtless taken up as nitrate, yet the
direct application of nitrate of soda has comparatively little
beneficial influence on their growth. The nitric acid is most
likely taken up chiefly as nitrate of lime, but probably as
nitrate of potash also, and it is significant that the high
nitrogen-yielding clover takes up, or at least retains, very
little soda. Table XI., from Warington's Chemistry of the
Farm, 19th edition (Vinton and Co.), will serve to illustrate
the subjects that have been discussed in this section.
For further information on the routine and details of
farming, reference may be made to the articles under
the headings of the various crops and implements.
British Live Stock.
The numbers of live stock in the United Kingdom are shown at
five-yearly intervals in Table XII. Under horses are embraced only
unbroken horses and horses used solely for agriculture (including
mares kept for breeding). The highest and lowest annual totals for
the United Kingdom in the period 1875-1905 were the following:--
Highest. Lowest. Difference
Horses 2,116,800 in 1905 1,819,687 in 1875 295,113
Cattle 11,674,019 in 1905 9,731,537 in 1877 1,942,482
Sheep 33,642,808 in 1892 27,448,220 in 1882 6,194,588
Pigs 4,362,040 in 1890 2,863,488 in 1880 1,498,552
After 1892 cattle, which in that year numbered 11,119,417,
and sheep declined continuously for three years to the
totals of 1895, the diminution being mainly the result
of the memorable drought of 1803. Sheep, which numbered
32,571,018 in 1878, declined continuously to 27,448,220 in
1882--a loss of over five million head in five years. This
was chiefly attributable to the ravages of the liver fluke
which began in the disastrously wet season of 1879. Pigs,
being prolific breeders, fluctuate more widely in numbers
than cattle or sheep, for the difference of 1,498,552 in their
case represents one-third of the highest total, whereas the
