Task: Working in pairs, use the following information to draw a soil profile (e.g. on the table with board pens)

There are four main horizons – O, A, B and C. These can be further divided into many more sub-horizons but for the purposes of this course – four is enough. Soils will not always have all the horizons.

The Organic horizon (referred to as the O horizon) is on the top of the soil and includes all the dead organic matter that accumulates on top of the soil, such as leaves. This is gradually decomposed.

The A horizon is the top soil layer. This layer is usually dark in colour due to the high proportion of humus (decomposed organic matter). The high organic content means it is a zone of highest biological activity. This layer has often lost clay and dissolved substances as it has been eluviated or washed out.

The B horizon is the sub-soil and tends to be the zone of illuviation or accumulation - minerals and particles are washed into this horizon from the ones above. Plant roots are likely to be found in this layer but very little humus is found here.

The C horizon is the decomposed parent material. In most cases this layer is not really affected by soil processes but it has weathered. This layer may contain large lumps of parent material.

The R horizon is hard rock.

Adapted from Kognity

Direct link to Wizer.me worksheet if you prefer: https://app.wizer.me/learn/6S2QYN

There are some great exam-style questions with guidance on Kognity.

Environmental Harm Caused by Intensive Farming

• The high use of fertilizers and pesticides can result in pollution of aquatic systems.
• Irrigation can result in soil salinisation.
• High crop production can result in soil nutrient deficiency and soil degradation.

Causes of Soil Degradation

• Water erosion.
• Wind erosion.
• Chemical degradation, such as salinisation, acidification, nutrient depletion and chemical pollution.
• Physical degradation, such as soil compaction.

Examples of Conservation Methods

• Soil conditioners (such as organic materials and lime)
• Wind reduction techniques (wind breaks, shelter belts)
• Cultivation techniques (terracing, contour ploughing, strip cultivation, no-till)
• Avoiding the use of marginal lands.

Pros and Cons of No-Till Agriculture

https://connectusfund.org/16-biggest-pros-and-cons-of-no-till-farming

https://greentumble.com/pros-and-cons-of-no-tillage-farming/

Case Study videos available on Kognity