"MICROENCAPSULATION OF PGPM AND ITS EFFECT ON pH AND EC DYNAMICS IN THE RHIZOSPHERE OF DIFFERENT CROPS AND IN SITU MONITORING WITH ELECTROCHEMICAL SENSORS"

• DOI: https://doi.org/10.22533/at.ed.515752606038

• Palavras-chave: microencapsulation, electrochemical sensors, rhizosphere

• Keywords: microencapsulation, electrochemical sensors, rhizosphere

• Abstract:

  The functional efficiency of plant growth-promoting microorganisms (PGPM) in real soil conditions depends on their stability, viability, and release kinetics in the rhizosphere. The present study evaluated a consortium of microencapsulated PGPMs under a completely randomized factorial design, integrating in situ electrochemical monitoring of pH, electrical conductivity (EC, dS m⁻¹), and soil temperature (°C), together with the early morphogenic response of four contrasting crops (Pisum sativum L., Zea mays L., Triticum aestivum L., and Phaseolus vulgaris L.). The physicochemical variables were recorded at six time points (10–59 days after application, DAA), while leaf number and height were evaluated at three sequential time points after initial inoculation. The general linear model indicated that pH dynamics were dominated by the temporal effect (F₅,₄₅₆ = 56.16; p < 0.0001; R² = 0.4058), with a progressive alkaline shift of Δ = 0.84 units between 10 and 59 DPA, without significant Crop × Time interaction, suggesting parallel trajectories between species. EC showed less structuring (R² = 0.1424), although with significant interaction (F₁₅,₄₅₆ = 2.18; p = 0.0064), evidencing interspecific dependence in ionic dynamics and a biphasic pattern with an intermediate maximum at 31 DDA. Temperature showed the highest proportion of explained variance (R² = 0.8104), with highly significant effects of Cultivation and its interaction with time, indicating microenvironmental modulation dependent on the plant species. In morphogenic terms, the number of leaves showed exceptional statistical adjustment (R² = 0.9893), dominated by the genotypic effect, while height showed greater temporal sensitivity (R² = 0.8111), consistent with a progressive physiological response following rhizospheric colonization. The integration of electrochemical and morphological data confirms that microencapsulation induced a gradual modification of the ionic and protonic equilibrium of the soil-plant system, with time-dependent and species-modulated effects. These results demonstrate that the controlled release of microencapsulated PGPM generates functional kinetics consistent with mineralization and differential absorption processes, and that in situ electrochemical monitoring is a robust tool for characterizing the edaphic dynamics associated with controlled-release bio-inputs.