Syllabus Edition

First teaching 2024

First exams 2026

Soil Conservation (DP IB Environmental Systems & Societies (ESS))

Revision Note

Written by: Alistair Marjot

Reviewed by: Bridgette Barrett

Soil Conservation Techniques

Soil conservation techniques are used to maintain the health and productivity of our soils
As soil fertility declines, various detrimental processes can occur, such as:
- Soil erosion
- Toxification
- Salinisation
- Desertification
These processes lead to significant environmental and agricultural challenges
Soil conservation techniques can be used to:
- Mitigate soil degradation
- Preserve the important characteristics of fertile soils
Soil conservation techniques can be classified in several ways, including:
1. Techniques that reduce soil erosion
2. Techniques that increase soil fertility (using soil conditioners)
3. Cultivation techniques

Conservation from Erosion

Soil conservation technique	Type of erosion reduced	Description	Effect
Strip cultivation	Water	Planting crops in alternating strips or bands, leaving natural vegetation between the strips	Reduces soil erosion by trapping water, slowing down runoff and increasing infiltration while still allowing for crop production in the cultivated strips Increases biodiversity
Terracing	Water	Creating levelled steps on sloped lands	Reduces soil erosion by slowing down water movement and increasing infiltration Minimises soil loss on steep slopes
Contour ploughing	Water	Ploughing parallel to the contour lines of the land instead of up and down slopes	Minimises soil erosion by reducing length and speed of water flow downhill Prevents gully formation and increases infiltration
Bunding	Water	Building embankments or barriers along fields	Controls water flow Prevents soil erosion and waterlogging
Drainage systems	Water	Installing systems to manage excess water	Prevents waterlogging Reduces erosion and nutrient loss
Cover crops	Water	Planting crops that cover the soil	Reduces water erosion Improves soil structure
Windbreaks	Wind	Planting trees or hedges to block and reduce wind speed	Provides physical barrier to wind Reduces wind erosion Protects topsoil Protects crops from wind damage
Cover crops	Wind	Planting crops to cover soil	Reduces wind erosion Adds organic matter to soil

Diagram showing three cultivation techniques: strip cultivation with maize, soybean, and oat; terracing with crops grown on stepped levels; and contour ploughing with a tractor on a contoured field. — **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**

Diagram showing wind reduction techniques. Three rows of trees of varying heights protect crops from prevailing winds. — **Wind reduction techniques help to minimise soil erosion and protect crops from wind damage**

Conservation of Fertility with Soil Conditioners

Soil conservation technique	Description	Effect
Lime	Adding lime to soil	Improves soil pH, reducing soil acidity Enhances nutrient availability Promotes beneficial microbial activity
Compost	Using decomposed organic matter	Enriches soil with nutrients Improves soil structure Increases water-holding capacity Promotes beneficial microbial activity
Green manure	Growing plants (e.g. cover crops) specifically to be ploughed into the soil	Increases organic matter Enhances soil fertility

Soil conservation technique

Description

Effect

Lime

Adding lime to soil

Improves soil pH, reducing soil acidity

Enhances nutrient availability

Promotes beneficial microbial activity

Compost

Using decomposed organic matter

Enriches soil with nutrients

Improves soil structure

Increases water-holding capacity

Promotes beneficial microbial activity

Green manure

Growing plants (e.g. cover crops) specifically to be ploughed into the soil

Increases organic matter

Enhances soil fertility

Two types of soil conditioners: a box labeled "Organic Soil Conditioner" and a jug labeled "Organic Pelletized Lime". — **Organic soil conditioners can be used to improve overall soil health, whilst the addition of lime helps to reduce soil acidity**

Cultivation Techniques

Soil conservation technique	Description	Effect
Avoid marginal land	Not farming on land that is vulnerable to erosion or poor in nutrients	Protects fragile ecosystems Prevents soil degradation Maintains soil health
Avoid overgrazing / overcropping	Managing livestock and crop levels to prevent depletion	Maintains soil cover Prevents soil erosion and compaction
Mixed cropping	Growing different types of crops together	Improves soil health Reduces pest and disease issues
Crop rotation	Rotating different crops on the same land	Maintains soil nutrients Reduces disease and pest buildup
Reduced tillage	Minimising ploughing and soil disturbance	Preserves soil structure Maintains moisture levels
Agroforestry	Integrating trees and shrubs into farming systems	Enhances soil structure Provides shade and wind protection
Reduced use of heavy machinery	Minimising the use of heavy equipment on fields	Prevents soil compaction Maintains soil structure

Diagram illustrating unsuitable steep, high-elevation land for farming, showing erosion and marginal soils. Promotes the use of fertile, level land. — 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

Examiner Tips and Tricks

You should note that many of these techniques help conserve soils in multiple ways. For example, cover crops protect the soil from wind and water erosion, but they can also ploughed into the soil to become green compost.

Last updated: 1 August 2024

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