BI303 Ecology: The Soil

These flashcards cover critical vocabulary related to soil ecology, nutrient cycling, and the interactions between soil biota and plant life, helping to prepare for exam topics.

Soil

A complex, 3-dimensional ecosystem created by the interaction of physical and chemical weathering of rock, sedimentation, climate, and living organisms.

Soil Fertility

The ability of soil to provide essential nutrients to plants, influenced by its physical, chemical, and biological components.

Nutrient Cycling

The circulation of nutrients through soil, primarily controlled by bacteria, which are affected by soil pH, aeration, temperature, and nutrient balance.

Humus

Decaying organic matter that contributes to soil structure and fertility, primarily found in the topsoil.

Topsoil

The uppermost layer of soil, consisting of a mixture of humus, minerals, and clay, where biological activity is concentrated.

Soil Profile

The vertical section of soil which displays different layers (horizons) from surface to bedrock with varying properties and composition.

Organic Matter (OM)

Material derived from living organisms, essential for maintaining soil fertility and supporting microbial life.

Microbial Respiration

The process by which soil microbes break down organic matter, releasing energy and nutrients back into the soil.

Aerobic Microbes

Microorganisms that require oxygen to decompose organic matter and are crucial for nutrient cycling in well-aerated soils.

Nitrogenase

An enzyme found in nitrogen-fixing bacteria that converts atmospheric nitrogen (N2) into organic ammonium (NH4+).

Mineralization

The process by which microbial activity releases excess nutrients from organic matter into a form that plants can use.

Immobilisation

The process whereby nitrogen and other nutrients are absorbed by bacteria during decomposition, reducing their availability for plants.

C:N Ratio

The ratio of carbon to nitrogen in soil, with an ideal range of 20:1 to 30:1 to ensure balanced nutrient cycling for plant health.

Soil Biota

The community of organisms in the soil, including bacteria, fungi, and invertebrates, that play vital roles in soil health and nutrient cycling.