Scientists Use Advanced Field Simulations to Understand How Soil Structure Changes Influence Water Retention Under Extreme Heat.
Researchers at the University of Illinois Urbana-Champaign are studying how drought-induced soil cracking affects water movement and storage in agricultural soils. Their findings could improve hydrological models used to manage water resources and better understand drought impacts.
Extended dry periods often cause soils to develop desiccation cracks. These openings alter soil structure and can accelerate moisture loss, making already dry conditions worse.
According to lead author Kristelle Dela Cruz, a doctoral student in the Department of Agricultural and Biological Engineering, the cracking process begins when moisture evaporates from the soil.
"As moisture evaporates from the soil, it induces stress. Once this stress exceeds the tensile strength of the soil, the soil breaks and desiccation cracks form. The cracks open additional surface area for moisture to transfer from the soil to the atmosphere, causing soil with cracks to become even drier," said Dela Cruz.
The research team examined how cracking changes soil structure and influences water dynamics. Co-author Maria Chu explained that soil texture refers to the proportions of sand, silt, and clay, while soil structure describes how these particles are arranged. Cracking disrupts that arrangement and changes the soil’s physical characteristics.
To investigate the process, researchers built a lysimeter capable of simulating field conditions. The device contained silt loess soil and was exposed to repeated wetting and drying cycles under temperatures reaching 40 degrees Celsius, replicating heat wave conditions.
"We cannot directly measure evaporation, but we can estimate the total loss of water from the soil by tracking the changes in weight through time, which can indicate the amount of water that has been lost from the system," said co-author Jorge Guzman.
The team also monitored crack formation using cameras and linked crack development to changes in soil moisture and evaporation rates. Their results showed that once cracks form, they often remain stable and continue influencing water movement.
Researchers believe the findings will help improve drought assessments and future water management strategies in agricultural systems.
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