Mechanical and Hydric Stress Effects on Maize Root System Development at Different Soil Compaction Levels

Area of Science:

• Agricultural Science
• Soil Science
• Agronomy

Background:

• Soil mechanical resistance, aeration, and water availability are critical factors influencing plant root development.
• Understanding the distinct roles of mechanical and hydric stresses is essential for optimizing crop growth, particularly in compacted soils.

Purpose of the Study:

• To quantify the individual contributions of mechanical and hydric stresses to maize root elongation.
• To develop and validate a new model for distinguishing these stresses in Oxisol under varying compaction levels.

Main Methods:

• Cultivated maize under four compaction levels: soil chiseling, no-tillage, tractor-trafficked, and harvester-trafficked areas.
• Measured root length density, soil bulk density, and soil water retention curves up to 50 cm depth.
• Developed a novel model to differentiate mechanical and hydric stress impacts on root growth.

Main Results:

• The new model accurately simulated maize root length density, showing good agreement with field data.
• Soil compaction, especially from harvester traffic and soil chiseling, reduced grain yield and shoot biomass compared to no-tillage.
• Mechanical stresses were dominant in trafficked areas, while hydric stresses were more significant in chiseled areas, both impeding root growth.

Conclusions:

• The developed model successfully distinguished mechanical and hydric stress impacts on maize root growth.
• Integrating mechanical and hydric stress dynamics into root growth models can improve predictions and inform better agricultural management practices.
• Coupling soil biophysical models with environmental data offers a pathway to enhance crop yield and soil health.