The National Ploughing Association of Ireland often holds its ploughing championships on brown earth soils - Leaving Cert Agricultural Science - Question 2 - 2012

A brown earth soil profile typically consists of multiple horizons:

1. O Horizon: Organic layer with decomposed leaves and plant material.
2. A Horizon (Topsoil): Rich in humus, dark brown color, high biological activity.
3. B Horizon (Subsoil): Lighter in color, accumulates minerals leached from above.
4. C Horizon (Parent Material): Weathered rock and minerals.
5. R Horizon: Bedrock (if applicable).

Make sure to label each layer clearly in your diagram.

Sandy Soil: Sandy soils have larger pore spaces, facilitating a rapid drainage of water. This prevents water-logging but may lead to less nutrient retention.

Clay Soil: Clay soils have smaller pore spaces, leading to poor drainage and slower water movement. This can result in water pooling and increased chances of waterlogging, adversely affecting root health.

Loam Soil: Loamy soils are considered ideal for fertility as they contain a balanced mix of sand, silt, and clay, promoting optimum nutrient retention and availability, along with good drainage.

1. Setup: Prepare two groups of identical plants, ensuring they are of the same species and age. Place one group in nutrient-rich soil with adequate phosphate and the other in low-phosphate soil.

2. Control: Ensure both groups receive the same amount of sunlight, water, and care, except for the phosphate content.

3. Observation: Monitor and record growth metrics such as height, leaf color, and overall health for several weeks.

4. Conclusion: Analyze the collected data. Plants in low-phosphate soil will likely show stunted growth, yellowing leaves, and poor overall health compared to those in the nutrient-rich soil.