Topic 5.1: Soil Systems Questions

Explain how leaching can reduce soil fertility in a wet climate.

The table below shows the sodium chloride (NaCl) concentration in irrigation water and the corresponding maximum grain yield of barley on the Nullarbor Plains, Australia. State the relationship between irrigation-water salinity and barley grain yield.

A student labels a soil diagram with O, A, B, C and R horizons. Outline what each horizon typically contains.

In a soil profile, which horizon is usually most important for plant growth and why?

A student uses CLORPT to explain why soils differ between two locations. Outline what each letter in CLORPT stands for.

The table below compares properties of three soil samples taken from sites with different levels of crop yield. Using the data and your knowledge, outline four characteristics that distinguish the high-yield soil from the low-yield soil.

Define the term soil profile.

A compost program increases organic matter in a school garden. Outline two ways higher organic matter can improve plant growth.

After a cold winter, a mountain road shows many new cracks in the rock face. Identify the type of weathering most likely responsible and state how it works.

A gardener notices that after rain, water disappears quickly from a light, gritty soil and plants wilt soon after. Identify the soil type most likely present.

A student measures soil pH at two sites. Site A has pH 5.0 and Site B has pH 6.5. Using the data, identify which site is closer to the preferred pH range of many crops and state the usual preferred range.

A soil profile shows a very thick O horizon and slow decomposition. Suggest which biome could produce this pattern and give one reason.

A student digs a soil pit in a forest and finds a surface layer of leaf litter and decomposing material. Identify the horizon most likely represented.

The graph below shows the percentage of normal tomato fruit set at different soil electrical conductivity (EC) values measured in irrigated greenhouses in the Almería basin, Spain. State the relationship between soil EC and tomato fruit set.

A field becomes waterlogged after heavy rain and is sticky when wet and hard when dry. Suggest which soil type is most likely and give one reason.

After a storm, a farmer notices muddy brown water flowing off a ploughed field into a nearby stream. Define the term soil erosion.

A dry irrigated farm starts showing a white crust on the soil surface and crops begin to wilt even though the soil looks wet. Identify the type of soil degradation described.

Define the term weathering.

Define the term soil texture.

The bar chart below shows mean annual soil-erosion rates (tonnes per hectare per year) on rangeland in the Ethiopian Highlands at five different slope gradients. State the relationship between slope gradient and mean annual soil-erosion rate.