Methods to estimate changes in soil water for phenotyping root activity in the field.

Area of Science:

• Agricultural Science
• Plant Science
• Soil Science

Background:

• Direct root excavation for phenotyping is labor-intensive.
• High-throughput field phenotyping of root systems is urgently needed.
• Inferring root activity from soil drying profiles is a potential alternative.

Purpose of the Study:

• To evaluate non-invasive methods for phenotyping wheat root systems.
• To compare the effectiveness of different soil sensing techniques for assessing root activity.
• To identify reliable methods for discriminating between wheat genotypes based on water uptake.

Main Methods:

• Grew 23 wheat lines over three years (2013-2015).
• Measured soil water profiles using electrical resistance tomography (ERT), electromagnetic inductance (EMI), penetrometer, and soil water content.
• Determined relationships between soil measurements, soil water content, and matric potential.

Main Results:

• ERT and penetrometer measurements strongly correlated with soil matric potential.
• These methods effectively distinguished between different wheat lines.
• Observed genotypic variations in water uptake depth and surface soil drying.

Conclusions:

• Penetrometer measurements provide a repeatable and reliable method for comparing wheat line soil drying profiles.
• ERT and penetrometer measurements are effective for discriminating wheat genotypes.
• Electromagnetic inductance (EMI) can rapidly screen large populations for root activity differences, especially in less dry soils.