Mineral content in the soil and tree foliage

Area of Science:

• Forestry and Environmental Science
• Plant Physiology and Nutrition

Background:

• Forest ecosystems face increasing stress from air pollutants like sulfur dioxide (SO(2)) and ozone (O(3)).
• Acidic precipitation (simulated rain at pH 4.0) was applied as a background stressor.
• Understanding pollutant impacts on tree nutrient cycling is crucial for forest health.

Purpose of the Study:

• To investigate the effects of SO(2), O(3), and combined SO(2) + O(3) fumigation on the nutrient content of fir (Abies alba) and spruce (Picea abies) seedlings.
• To analyze nutrient dynamics in soil, soil solutions, and tree tissues under chronic pollutant exposure.

Main Methods:

• Seedlings were exposed to SO(2), O(3), and SO(2) + O(3) in open-top chambers for nearly five years.
• Simulated acid rain (pH 4.0) was applied concurrently.
• Nutrient content analysis was performed on soil, soil solutions, and needles of the trees.

Main Results:

• Elevated concentrations of exchangeable calcium (Ca(2+)) were observed in the upper soil layer across all treatments.
• SO(2) and SO(2) + O(3) treatments significantly increased Ca(2+), magnesium (Mg(2+)), and manganese (Mn(2+)) in soil solutions, alongside increased exchangeable protons.
• Needle analysis revealed increased manganese (Mn) and sulfur (S) levels under SO(2) exposure, while calcium (Ca) content showed a declining trend; O(3) alone had minimal impact.

Conclusions:

• Chronic exposure to SO(2), particularly when combined with O(3), alters soil nutrient availability and tree nutrient uptake.
• The observed decrease in needle calcium suggests potential nutrient imbalances and stress in fir and spruce seedlings.
• Ozone alone did not consistently affect needle nutrient content, indicating differential impacts of these major air pollutants.