This was
confirmed by a number of later workers, among them, for instance,
Buergerstein, who, in 1875, showed that whenever acids were added to
a soil or to water in which plants are growing, the transpiration is
increased greatly; but when alkalies of any kind are added,
transpiration decreases. This is of special interest in the
development of dry-farming, since dry-farm soils, as a rule, contain
more substances that may be classed as alkalies than do soils
maintained under humid conditions. Sour soils are very
characteristic of districts where the rainfall is abundant; the
vegetation growing on such soils transpires excessively and the
crops are consequently more subject to drouth.
The investigators of almost a generation ago also determined beyond
question that whenever a complete nutrient solution is presented to
plants, that is, a solution containing all the necessary plant-foods
in the proper proportions, the transpiration is reduced immensely.
It is not necessary that the plant-foods should be presented in a
water solution in order to effect this reduction in transpiration;
if they are added to the soil on which plants are growing, the same
effect will result.
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