5.1: Introduction to soil systems Significant ideas: The soil system is a dynamic ecosystem that has inputs, outputs, storages and flows. The quality of soil influences the primary productivity of an area. Knowledge and understanding: Guidance: The soil system may be illustrated by a Studies of specific soil profiles, such as soil profile that has a layered structure podsol, are not required. (horizons). Familiarity with the soil texture triangle Soil system storages include organic diagram used for soil type classification matter, organisms, nutrients, minerals, based on the percentage of sand, silt, air and water. and clay in the soil is required. Transfers of material within the soil, International-mindedness: including biological mixing and leaching (minerals dissolved in water moving Significant differences exist in arable through soil), contribute to the (potential to promote primary organization of the soil. productivity) soil availability around the There are inputs of organic material world. These differences have including leaf litter and inorganic matter sociopolitical, economic and ecological from parent material, precipitation and influences. energy. Outputs include uptake by plants and soil erosion. Theory of knowledge: Transformations include decomposition, weathering and nutrient cycling. The soil system may be represented by a The structure and properties of sand, soil profile—since a model is, strictly clay and loam soils differ in many ways, speaking, not real, how can it lead to including mineral and nutrient content, knowledge? drainage, water-holding capacity, air Connections: spaces, biota and potential to hold organic matter. Each of these variables is ESS: Communities and ecosystems linked to the ability of the soil to promote (2.2); flows of energy and matter (2.3); primary productivity.
5.1: Introduction to soil systems Significant ideas: The soil system is a dynamic ecosystem that has inputs, outputs, storages and flows. The quality of soil influences the primary productivity of an area. Knowledge and understanding: The soil system may be illustrated by a soil profile that has a layered structure (horizons). Soil system storages include organic matter, organisms, nutrients, minerals, air and water. Transfers of material within the soil, including biological mixing and leaching (minerals dissolved in water moving through soil), contribute to the organization of the soil. There are inputs of organic material including leaf litter and inorganic matter from parent material, precipitation and energy. Outputs include uptake by plants and soil erosion. Transformations include decomposition, weathering and nutrient cycling. The structure and properties of sand, clay and loam soils differ in many ways, including mineral and nutrient content, drainage, water-holding capacity, air spaces, biota and potential to hold organic matter. Each of these variables is linked to the ability of the soil to promote primary productivity. Guidance: Studies of specific soil profiles, such as podsol, are not required. Familiarity with the soil texture triangle diagram used for soil type classification based on the percentage of sand, silt, and clay in the soil is required. International-mindedness: Significant differences exist in arable (potential to promote primary productivity) soil availability around the world. These differences have sociopolitical, economic and ecological influences. Theory of knowledge: The soil system may be represented by a soil profile—since a model is, strictly speaking, not real, how can it lead to knowledge? Connections: ESS: Communities and ecosystems (2.2); flows of energy and matter (2.3);