Functional persistence of hydrogels in soil and their effects on maize tolerance to water deficit

• Grant number: 25/22985-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2025
• End date: October 31, 2026
• Field of knowledge: Agronomical Sciences - Agricultural Engineering - Soil and Water Engineering
• Principal Investigator: Fernando Ferrari Putti
• Grantee: Izabelle Cunha de Moraes
• Host Institution: Faculdade de Ciências e Engenharia. Universidade Estadual Paulista (UNESP). Campus de Tupã. Tupã , SP, Brazil
• Associated research grant: 25/13844-0 - Functional Persistence of Hydrogels in Soil and Their Effects on Maize Drought Tolerance, AP.R

Abstract

Hydrogels are hydrophilic polymers with a high capacity for water absorption and retention, acting as temporary moisture reservoirs in the soil. Their application has shown beneficial effects on plant physiology, such as increased water use efficiency, maintenance of leaf turgor, and stability of gas exchange under limited irrigation conditions. Thus, the hypothesis is that the efficiency of hydrogels in mitigating water stress in maize varies according to their decomposition rate. The project will therefore evaluate the functional persistence of hydrogels in the soil and their residual effects on maize tolerance to water deficit through two complementary experiments. In Experiment 1 (greenhouse), maize will be grown in pots for three consecutive cycles, with a single hydrogel application in the first cycle. The experimental design will follow a randomized block layout (five replicates) in a (2 sources × 3 doses) + 1 arrangement: carboxymethyl cellulose (CMC) or sodium polyacrylate (SAP) at doses of 0%, 0.5%, and 1.5% (w/w), plus a continuously irrigated control. After stage V5, all treatments-except the irrigated control-will receive only 50% of the crop water requirement until V8-V9. Gas exchange, chlorophyll fluorescence, protein content, antioxidant enzymes, H¿O¿, MDA, growth, and biomass will be monitored in each cycle, allowing the quantification of the residual effectiveness of the hydrogels. Understanding the degradation kinetics of hydrogels in the soil and associating them with the crop's physiological response over multiple cycles is fundamental to better understanding the functional durability of these inputs in the soil, providing a scientific basis for more efficient and sustainable agronomic recommendations.