Soil Analysis and Environmental Monitoring

Soil Analysis - Aspects of Environmental Monitoring

• Soil analysis is a crucial aspect of environmental monitoring.
• Physical factors, like light, temperature, water, and nutrients, are essential for organisms.
• Organisms actively modify their physical environments to meet their needs.
• Human activities significantly impact the environment.

Why Study the Physical Environment?

• The physical environment is vital for all living organisms.
• Anthropogenic activities have drastically altered air, water, and land quality.
• The study focuses on physical and chemical factors essential for organisms' life cycles.

Objectives

• To define the range of physical factors measured in environmental monitoring.
• To understand the ecological significance of these factors.
• To outline the methods used to measure physical factors within the soil.

Soil Quality

• Humans depend on soil for survival, crucial for food, wood, medicine, and animal life.
• Soil quality is directly tied to human living standards.
• Human activities, like continuous cultivation, fertilizer and pesticide use, and acid rain, negatively impact soil quality.

Common Indicators for Soil Quality

• Soil pH: A key parameter to detect changes in soil reaction.
• pH impacts microorganisms and plants significantly.
• Three states possible in the soil: acidity, neutrality, and alkalinity.

Soil pH and Chemical Attributes

• Very acidic soil is dominated by aluminum ions.
• Trace elements in the soil are high in very acidic soils, but other essential elements are low.
• Higher pH values indicate the dominance of exchangeable soil bases.
• A pH range of approximately 6-7 is optimal for plant growth.

Determining Soil pH

• Electrometric method provides the most accurate measurement.
• Dye method presents a simpler but less accurate approach.
• Different dyes are used to determine a range of pH. The soil is saturated and then color is observed after contact, to estimate the pH.

Soil Organic Matter (SOM)

• SOM content significantly influences soil fertility.
• 25% of SOM is usually lost after forest clearing.
• Continuous ploughing, drainage, and liming accelerate soil depletion.
• SOM serves as a vital indicator of soil quality.

Soil Moisture (SM)

• Soil moisture is fundamental to plant life and environmental studies.
• Rainfall, evaporation, and percolation are crucial processes.
• Waterlogged soil signifies saturated conditions.
• Field capacity is a critical stage of soil moisture.
• Wilting point occurs when plants cannot extract water from the soil.

Gravimetric & Neutron Scattering Methods for Measuring Soil Moisture

• Gravimetric methods are highly reliable for estimating soil moisture.
• Soil samples are heated to evaporate the moisture, and the dry weight is obtained.
• Neutron scattering uses radioactivity to determine soil moisture.
• The principle involves measuring the number of slow neutrons, correlated with water content.

Soil Salinity

• Salinity relates to the accumulation of soluble salts like sodium, calcium, magnesium, and potassium.
• Chloride and sulfate are primarily found as anions.
• Excessive salt buildup can stem from evaporation, or sea water intrusion.
• Salinity reduces soil quality and its productivity.

Pollutants in Soils

• Soils can retain, modify, decompose, or absorb pollutants like atmospheric and solid wastes.
• Biodegradable organic matter breaks down into safe substances.
• Human activities lead to the accumulation of harmful pollutants in the soil.
• Metal mining, industrial, agricultural, and commercial activities are sources of soil contamination.

Determining Soil Pollutants

• Instrumental methods including Gas Chromatography and Atomic Absorption Spectroscopy can detect soil pollutants.

Soil Plant Ecology Data

• Soil data (color, texture, moisture, pH) is essential for environmental studies.
• Collected data is important to assess and predict soil quality.