Compacted and poorly drained soils contains little ___ needed by tree roots to survive and grow

Compacted and poorly drained soils contains little ___ needed by tree roots to survive and grow

• A. Iron
• B. Oxygen
• C. Carbon dioxide
• D. Magnesium

Answer: (B)

Oxygen availability in soil governs root respiration. In compacted, poorly drained soils, the pore spaces are compressed and water fills the voids, which severely restricts how quickly oxygen can diffuse to root hairs. Without enough oxygen, root cells can’t efficiently release energy from sugars, so growth slows or roots die. Carbon dioxide is produced during respiration and isn’t required from soil input; low CO2 isn’t the limiting factor. Magnesium and iron are nutrients the plant needs, but the immediate constraint in compacted, waterlogged soils is lack of oxygen.

Oxygen availability in soil governs root respiration. In compacted, poorly drained soils, the pore spaces are compressed and water fills the voids, which severely restricts how quickly oxygen can diffuse to root hairs. Without enough oxygen, root cells can’t efficiently release energy from sugars, so growth slows or roots die. Carbon dioxide is produced during respiration and isn’t required from soil input; low CO2 isn’t the limiting factor. Magnesium and iron are nutrients the plant needs, but the immediate constraint in compacted, waterlogged soils is lack of oxygen.