The addition of commercial fertilizers to the
soil will therefore diminish transpiration. It was further
discovered nearly half a century ago that similar plants growing on
different soils evaporate different amounts of water from their
leaves; this difference, undoubtedly, is due to the conditions in
the fertility of the soils, for the more fertile a soil is, the
richer will the soil-water be in the necessary plant-foods. The
principle that transpiration or the evaporation of water from the
plants depends on the nature and concentration of the soil solution
is of far-reaching importance in the development of a rational
practice of dry-farming.
Transpiration for a pound of dry matter
Is plant growth proportional to transpiration? Do plants that
evaporate much water grow more rapidly than those that evaporate
less? These questions arose very early in the period characterized
by an active study of transpiration. If varying the transpiration
varies the growth, there would be no special advantage in reducing
the transpiration. From an economic point of view the important
question is this: Does the plant when its rate of transpiration is
reduced still grow with the same vigor? If that be the case, then
every effort should be made by the farmer to control and to diminish
the rate of transpiration.
Pages:
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183