Growth response to different constant soil moisture levels in maize (Zea mays L.) during the vegetative phase

Abstract

The effect of different constant soil moisture levels (90, 60, 30% and 90, 60, 40% respectively, of the maximum capillary capacity) on the vegetative growth of maize was studied by the methods of growth analysis. The constant soil moisture in vegetation pots was maintained by means of the injection method. The constantly decreased soil moisture was applied in one experiment just from the sowing of germinated corns and in the other from the phase of 4–6 leaves. In both the cases plants responded to the different soil moisture levels by a progressively lower growth rate of the total dry weight according to the degree of soil moisture lowering. When the constant soil moistures were applied from the sowing, the differences in the relative growth rate (R.G.R.) were caused mainly by lower leaf area ratio (L.A.R.) values. In the case of constantly lowered soil moistures from the phase of 4–6 leaves, the differences in R.G.R. were caused by lower net assimilation rate (N.A.R.). When the constant soil moisture of 40% was applied from the sowing, the changes in N.A.R. showed the characteristic features of adaptation to unfavourable conditions.