2nd

• Human activities that affect the quality and quantity of soil include soil compaction, overgrazing, and the use of chemicals.
• Soils are complex mixtures of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things.
• Soils form at the surface of land and are the "skin of the earth".
• Planting trees also contributes to prevent soil erosion by improving water infiltration in the ground, so that water runoff will be reduced.
• Moist soil serves as an anchor for soil.
• Moist soil is not in danger of erosion due to wind activity.
• Soils serve as media for growth of all kinds of plants.
• Soils modify the atmosphere by emitting and absorbing gases (carbon dioxide, methane, water vapor, and the like) and dust.
• Soil naturally absorbs carbon from the atmosphere through a process known as Carbon Sequestration which not only reduces harmful greenhouse gases but also creates more fertile soil.
• Soils provide habitat for animals that live in the soil (such as groundhogs and mice) to organisms (such as bacteria and fungi), that account for most of the living things on Earth.
• Soils are Nature’s Reservoir, holding water for use by plants and serving as an aquifer.
• Soils serve as engineering media for construction of foundations, roadbeds, dams and buildings.
• The particles that make up soil are categorized into three groups by size: sand (2.0 to 0.05 mm), silt (0.05 to 0.002 mm), and clay (less than 0.002 mm).
• Soil structure is the arrangement of soil particles into small clumps, called peds or aggregates which are the 'building blocks' of the soil.
• Soil particles (sand, silt, clay and even organic matter) bind together to form peds.
• Structure correlates to the pore space in the soil which influences root growth and air and water movement.
• Granular soils with a loamy texture make the best farmland, for example, because they hold water and nutrients well.
• Single-grained soils with a sandy texture don’t make good farmland, because water drains out too fast.
• Soil color can tell us about the soil’s mineral content, with soils high in iron being deep orange-brown to yellowish-brown.
• Most soils have three major horizons (A, B, C) and some have an organic horizon (O).
• Soil degradation is a human-induced or natural process which impairs the capacity of soil to function, usually caused by its improper use or poor management, usually for agricultural, industrial or urban purposes.
• Lime and mineral fertilizers added to soil provide stable optimum growing conditions for plants.
• Mining digging of mines and open pit mines involves the removal of plants and soil from the surface of the ground.
• Overgrazing when farmers allow to many animals to graze an area of pand, damages the soil structure and removes plant cover, allowing the soil to blow away.
• Rodale Institute's Farming Systems Trial includes soybeans as part of a complex crop rotation that includes corn, wheat, oats, and other small grains.
• Construction and development involve digging up the soil, some of which washes or blows away because its protective plant cover has been removed.
• Overcropping occurs when land is continuously farmed, draining nutrients from the soil which destroys soil structure and makes it less fertile.
• Deforestation involves cutting down large areas of forest, leaving bare landscape and soil erosion.
• Conservation methods include contour/strip ploughing, terracing, stone walls/bunds, crop rotations, and watering the soil.
• Contour/strip ploughing involves following the contours of the hillside, throwing up furrows that stop the flow of water and increase infiltration in the soil.
• Stone walls/bunds are low walls placed along the contour of a hill, capturing water and allowing it to filter into the soil rather than run off downhill.
• Watering the soil along with plants and vegetables is important to nourish the soil and protect it.
• Most soil erosion is caused by natural processes such as water flowing downhill and by the wind.
• Irrigation/ drainage water stabilizes the moisture thus making it healthier and more stable for planting.
• Terracing keeps the soil from moving very far downhill since it will only get as far as the next terrace downhill.
• Crop rotations are the practice of planting different crops sequentially on the same plot of land to improve soil health, optimize nutrients in the soil, and combat pest and weed pressure.
• Farming can cause damage to soil microorganisms that are important for the fertility status of the soil.
• Growing plants help in stabilizing the soil structure.