PHYSIOLOGICAL REACTIONS AND INITIAL GROWTH OF TUXPEÑO CORN WITH VERMICOMPOST AND IRRIGATION SUSPENSION

Background: The water deficit in the early stages of corn cultivation determines the survival of the seedlings and the establishment of the crop, so it is desirable that the soil can conserve available moisture for long periods of time. Organic fertilizers improve water holding capacity of soil, although studies of their effect on water deficit conditions are scarce. Objective: To evaluate the effect of vermicompost on soil moisture and the physiology and growth of corn seedlings. Methodology: In greenhouse conditions, a completely randomized experiment with factorial arrangement was designed. Two cultivars of Tuxpeño corn (tolerant and susceptible to drought) grown in a substrate composed of a mixture of agricultural soil and 0, 1.5 and 3% of vermicompost were evaluated. The field capacity, the permanent wilting point, and the water potential (ΨA) of the substrate were recorded. In the seedlings, from the fifth ligulate leaf, stomatal conductance (gs), transpiration (E), CO2 assimilation (A), biomass and proline contents were measured. Results: There was an increase in the permanent wilting point values, but not in field capacity, therefore the water usable decreased with the vermicompost. In the seedlings grown in the mixture with 1.5 and 3% of vermicompost, the gs, A and E decreased. At higher proportion of vermicompost the root biomass increased. The cultivar x vermicompost interaction for gs and root biomass production was evidenced. No significant difference in proline content was observed. Implications: In this study the early vegetative stage and the total suspension of irrigation were evaluated, the evaluation of the complete biological cycle of the crop with intermittent suspension of irrigation is required to generate greater knowledge of the processes involved in the soil-crop dynamics. Conclusion: Vermicompost promoted biomass production, although the physiological parameters and water usable on soil decreased.