Syllabus Edition
First teaching 2015
Last exams 2025
Soil Conservation (DP IB Environmental Systems & Societies (ESS))
Revision Note
Written by: Alistair Marjot
Reviewed by: Bridgette Barrett
Soil Conservation
Soil conservation measures play a crucial role in maintaining the health and productivity of our soils
As soil fertility declines, various detrimental processes like soil erosion, toxification, salinisation, and desertification can occur, leading to significant environmental and agricultural challenges
Soil conservation measures, including soil conditioners, wind reduction techniques, cultivation techniques, and the avoidance of marginal lands can be used to mitigate soil degradation and preserve the vital characteristics of fertile soils
Soil Conservation Measures
Soil conservation measure | Description | Effect |
|---|---|---|
Soil conditioning: organic materials | Application of organic materials, such as compost or manure, to improve soil structure and nutrient content | Enhances soil fertility, increases water holding capacity, promotes microbial activity, and improves overall soil health |
Soil conditioning: lime | Addition of lime to adjust soil pH and reduce acidity | Neutralises soil acidity, improves nutrient availability, and enhances microbial activity, leading to healthier plant growth |
Wind reduction: wind breaks | Planting rows of trees or tall vegetation perpendicular to prevailing winds to reduce wind speed and deflect airflow | Provides a physical barrier to wind, reducing soil erosion, protecting crops from wind damage, and creating microclimates that favour plant growth |
Wind reduction: shelter belts | Planting multiple rows of trees or shrubs in a staggered pattern to create a windbreak system | Offers effective wind protection by trapping and redirecting wind, reducing soil erosion, protecting crops, and enhancing biodiversity in the surrounding area |
Cultivation: terracing | Creating levelled steps on sloped lands to reduce erosion by preventing runoff and promoting water infiltration | Controls soil erosion by slowing down water movement, allowing water to soak into the soil, and minimising soil loss on steep slopes |
Cultivation: contour ploughing | Ploughing parallel to the contour lines of the land instead of up and down slopes | Minimises soil erosion by reducing the length and speed of water flow downhill, preventing gully formation, and promoting water infiltration into the soil |
Cultivation: strip cultivation | Planting crops in narrow strips or bands across the slope, leaving natural vegetation between the strips | Reduces soil erosion by trapping water, slowing down runoff, and promoting infiltration while still allowing for crop production in the cultivated strips |
Avoiding marginal lands | Refraining from agricultural activities on marginal lands with unsuitable soil conditions or high susceptibility to erosion | Protects fragile ecosystems, prevents soil degradation, and avoids the loss of valuable resources by focusing agricultural activities on more suitable and productive lands |
These soil conservation measures aim to improve soil health, reduce erosion, and promote sustainable land use
By enhancing soil structure, reducing wind erosion, adopting appropriate cultivation techniques, and avoiding the use of unsuitable lands, these practices help to maintain soil fertility, retain moisture, and protect the soil from degradation, ensuring long-term productivity and environmental sustainability
Organic soil conditioners can be used to improve overall soil health, whilst the addition of lime helps to reduce soil acidity
Wind reduction techniques help to minimise soil erosion and protect crops from wind damage
Strip cultivation, terracing, and contour ploughing all help to conserve soils by slowing the speed of water runoff, which allows water time to infiltrate the soil, minimising soil erosion
Marginal lands (usually steep land with poor soil structure and low fertility) are already vulnerable to soil erosion, so should not be used for agricultural purposes as this will quickly result in significant soil degradation in these areas
Worked Example
Evaluate the soil management strategies of commercial farming systems and subsistence farming systems.
Answer
Commercial Farming Systems:
Soil management strategies in commercial farming systems typically prioritise high yields and profitability. Intensive tillage methods, such as mechanical ploughing, may be used to prepare the soil for planting, but this can increase the risk of erosion and soil compaction. Synthetic fertilisers are often applied to provide nutrients for crop growth, but excessive use can lead to nutrient imbalances and pollution of water bodies through runoff. Pesticides and herbicides may be utilised for pest and weed control, but they can have negative impacts on soil biodiversity and overall ecosystem health. Commercial farming systems use soil conservation measures such as soil conditioning, wind reduction, contour ploughing and generally avoid using marginal lands for agriculture. By focusing on more fertile and suitable lands, commercial farming systems can optimise resource utilisation and minimise negative environmental impacts.
Subsistence Farming Systems:
Subsistence farming systems often rely on traditional practices to enhance soil fertility. Organic materials such as crop residues, animal manure, and compost are commonly used as soil conditioners and fertilisers. These materials help replenish nutrients, improve soil structure, and enhance water-holding capacity. Traditional practices such as slash-and-burn agriculture or shifting cultivation may be used, where farmers clear small plots of land, cultivate them for a few years, and then leave them fallow to regenerate. Crop rotation and intercropping techniques are also often employed to optimise nutrient cycling and maximise yields. Soil conservation measures like terracing and contour plowing may be implemented to control erosion, retain soil moisture, and enhance soil fertility. Subsistence farming systems often make use of marginal lands due to limited access to more fertile areas. These marginal lands may have lower soil fertility and higher erosion risk. However, subsistence farmers often adopt sustainable practices, such as mixed cropping, agroforestry, and crop rotation, to improve soil health and mitigate erosion on these lands. These practices help optimise resource utilisation and enhance food security in challenging environments.
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