Experimental Assessment of the Effects of a Lignin-Based Hydrogel on Saturated Hydraulic Conductivity in Soils with Different Textures

Climate change represents a major environmental challenge that adversely affects soil hydrological regimes and water availability for plants. The increasing frequency and intensity of drought events lead to reduced soil moisture, limited infiltration, and deterioration of soil hydrophysical properties, thereby directly constraining crop growth, development, and yield potential. Insufficient soil water availability disrupts key physiological processes in plants, restricts nutrient uptake, and increases vulnerability to abiotic stress.

One promising adaptation strategy to mitigate the adverse effects of drought is the application of hydrogels in agricultural systems. Hydrogels are polymeric materials capable of absorbing and retaining large amounts of water within their structure and subsequently releasing it gradually into the surrounding soil environment. When incorporated into soil, hydrogels can improve soil water regimes and potentially enhance soil hydrophysical properties.

In this study, two soils differing in texture (sandy clay and sandy loam) and a lignin-based hydrogel at 2% application rate were investigated under laboratory conditions. Four incubation periods were established to evaluate the temporal effects of hydrogel application: 1 day, 1 month, 3 months, and 6 months. Saturated hydraulic conductivity was determined using the falling head method.

The results demonstrated that, in sandy clay soil, increasing incubation duration resulted in a statistically significant increase in saturated hydraulic conductivity, ranging from 400 to 800%. In contrast, sandy loam soil exhibited a statistically non-significant decrease (3–10%) during the initial incubation stages, followed by a statistically significant increase of approximately 60% after 6 months. These findings indicate that hydrogel incubation time in combination with soil texture is a key determinant of both the direction and magnitude of hydrogel effects on soil hydrophysical properties.

Overall, the application of lignin-based hydrogels may represent an innovative approach to enhancing agroecosystem resilience to climate change and drought, while supporting sustainable soil and water management at the landscape scale.

 

Keywords: hydrogel, saturated hydraulic conductivity, drought, climate change

 

Acknowledgement: The authors would like to thank the National Agency of Academic Exchange for the financial support (NAWA, Strategic Partnerships, BNI/PST/2023/1/00108) and the Scientific Grant Agency (VEGA 2/0065/24).