LAND2003 The Soil Environment Practice Exam Flashcards

A set of practice flashcards covering soil properties, nutrient cycling, and land management concepts from the LAND2003 Semester 1 Examinations.

Which soil property directly affects plant-available water storage?

Soil texture

In a well-structured soil, what is the primary benefit of macropores?

Facilitating water infiltration and air exchange

Which soil amendment is effective for increasing soil water retention?

Organic matter (compost)

What is the main reason why sandy soils typically have lower fertility than clay soils?

Low organic matter content

Which process primarily contributes to the improvement of soil aggregation and structure?

Organic matter decomposition

Why do soil colloids play an important role in the soil nutrient/contaminant cycle?

They have a high cation exchange capacity (CEC)

What forces primarily drive the movement of water through soil due to capillary action?

Cohesion and adhesion forces

What is the primary cause of soil compaction in urban environments?

Heavy traffic and construction

Which role does soil microbial activity play in environmental processes?

It contributes to both nutrient cycling and contaminant degradation

What is the best strategy to mitigate soil erosion in areas prone to land degradation (e.g., agricultural, deforested, construction, or mining sites)?

Establishing vegetation cover, such as grasses, trees, shrubs, or bioengineering solutions

What is the most significant environmental concern associated with nitrate leaching in urban and rural landscapes?

Groundwater and surface water contamination

Which element mentioned in the exam is classified as a macronutrient for plants?

Potassium ($K$)

What is the dominant process for plants when acquiring Phosphorus ($P$) from the soil?

Via diffusion

Under what condition is net mineralisation most likely to occur in soil regarding the $C:N$ ratio?

When an organic residue with a $C:N$ ratio of $12$ is added

In which part of the plant are symptoms of Sulfur ($S$) deficiency (chlorosis) most likely to be observed?

Younger leaves

What is the definition of Cation Exchange Capacity (CEC)?

A measure of the soil's ability to hold and exchange cations, determining its ability to retain nutrients or contaminants.

How do sandy soils and clay-rich soils compare in terms of Cation Exchange Capacity (CEC)?

Clay-rich soils typically have a higher CEC than sandy soils, allowing them to better retain nutrients and contaminants.

How does soil structure differ from soil texture?

Soil texture is the relative proportion of sand, silt, and clay particles, while soil structure is the arrangement or grouping of these particles into aggregates (peds).

How does soil organic matter ($SOM$) contribute to carbon storage?

It acts as a reservoir for carbon, which is stored as soil organic carbon ($SOC$).

What are two identified causes of soil acidification according to the exam content?

Natural processes over time and acceleration due to poor management practices.

If a plant shows chlorosis, which two specific nutrient deficiencies are commonly suspected together?

Nitrogen ($N$) or Magnesium ($Mg$) deficiency

What relationship exists between soil texture and water infiltration/retention?

Different textures (sand, silt, clay) determine the size and distribution of pores, which in turn controls the rate of water movement (infiltration) and the soil's capacity to hold water (retention).