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FOOD OF PLANTS. 
Class 3. Roots. 
Water, per cent. 
Potatoes, round pinkeyes,.... 79-54 
“ blue pinkeye,. 73-71 
“ pinkeye,. 75- 
“ Scotch gray,. 71* 
Orange carrot,. from 83 to 89*52 
Blood beet. 86-42 
Turnips,. 88* 
Mangel wurtzel,. 85- 
It will be observed, on comparing the foregoing classes, that water is much greater in the 
roots than grain. The state in which these classes are fed, is also worthy of note ; the grains 
and grasses are fed dry, while the roots are fed green, they being so constituted as to retain 
their water for a long time after they are removed from the earth ; while grains and grass be¬ 
come dry and are fed in that condition. The amount retained in the grains and grasses does 
not differ materially, and if the root should undergo a like depreciation, they would resemble 
the herbage of plants; the grasses when green lose on drying about 80 per cent of water. 
Now, from the great amount of water which roots contain, and the small percentage of ash, 
it has been maintained that they exhaust a soil less than the grains; that the potato and turnip 
may be grown without regarding very particularly the matter removed. In potash, however, 
the exhaustion must be admitted to be excessive, when the great amount of substance re¬ 
moved is taken into account. The nutritious matter of the root crops, which is derived ordi¬ 
narily from an acre of ground, exceeds considerably that which is furnished by wheat, and 
rather more than that which is produced by Indian corn. These facts seem to show that really 
in the peculiar elements of roots their exhausting power exceeds that of wheat, corn or beans. 
These heavy root crops are usually fed to stock upon the farm, and hence there is no loss of 
mineral matter. 
IMPORTANCE OF SUPPLYING PLANTS WITH PROPER FOOD. 
Plants are not confined absolutely to certain kinds of food ; their aliment may be varied, 
and they will preserve, externally, their natural characteristics, provided this variation is not 
excessive. It appears, from observation and experiment, that to a certain extent one element 
of food may be substituted for another ; soda and lime, for example, may take the place of 
potash. It is not a matter of indifference whether tobacco and other plants contain lime or 
potash. It may not be necessary to follow the natural affinities of the plant; what we have 
to do is to ascertain the effect of these aliments on their qualities or properties. If the salts 
of lime predominate in tobacco its qualities are injured. It matters not whether tobacco is a 
potash or lime plant, in a state of nature, or has preference for lime rather than for potash ; it 
is a fact merely, and by change from necessity, may affect the properties favorably. It is pro- 
