Soil contamination is primarily caused by human activities, such as industrial activities, agricultural practices, and household waste disposal. Natural processes, such as weathering and erosion, can also contribute to soil contamination, but they are not the primary source.

Bioremediation is a process that uses microorganisms to break down and remove contaminants from soil. Phytoremediation is a similar process that uses plants to absorb and remove contaminants from soil. Excavation and landfilling are methods of removing contaminated soil from a site, but they do not involve the removal of contaminants from the soil itself.

Soil conservation practices, such as terracing, contour farming, and cover cropping, are designed to reduce soil erosion and improve water quality. They do not directly reduce the risk of flooding, which is primarily caused by excessive rainfall or snowmelt.

Afforestation is the practice of planting trees and other vegetation in areas that were previously not forested. Reforestation is the practice of planting trees in areas that were previously forested but have been cleared. Agroforestry is the practice of integrating trees and other vegetation into agricultural systems. Silviculture is the practice of managing forests for the production of timber and other forest products.

Crop rotation, contour farming, and fertilization are all soil management practices that are used to improve soil health and productivity. Irrigation is a water management practice that is used to provide water to crops, but it is not a soil management practice.

Decomposition is the process by which organic matter in soil is broken down by microorganisms into simpler compounds. Mineralization is the process by which organic matter is converted into inorganic compounds, such as nitrates and phosphates. Nitrification is the process by which ammonia is converted into nitrates. Denitrification is the process by which nitrates are converted into nitrogen gas.

Soil texture, soil structure, and soil pH are all factors that affect soil fertility. Soil temperature is not a direct factor that affects soil fertility, but it can indirectly affect soil fertility by influencing the activity of soil microorganisms and the availability of nutrients to plants.

Fertilization is the process of adding nutrients to soil to improve plant growth. Composting is the process of converting organic matter into a nutrient-rich soil amendment. Manuring is the process of adding manure to soil to improve soil fertility. Mulching is the process of covering the soil with a layer of organic material to help retain moisture and suppress weeds.

Water erosion, wind erosion, and sheet erosion are all types of soil erosion. Rill erosion is not a type of soil erosion, but rather a stage of soil erosion that occurs when water runoff forms small channels in the soil.

Soil conservation is the process of managing soil to prevent degradation. Soil management is a broader term that encompasses soil conservation as well as other practices that improve soil health and productivity. Land management is the process of managing land resources, including soil, water, and vegetation. Water management is the process of managing water resources, including water quality and quantity.

Compost, manure, and fertilizer are all types of soil amendments that are added to soil to improve its fertility and structure. Mulch is not a soil amendment, but rather a material that is applied to the surface of the soil to help retain moisture and suppress weeds.

Composting is the process of converting organic matter, such as food scraps, yard waste, and paper products, into a nutrient-rich soil amendment. Manuring is the process of adding manure to soil to improve soil fertility. Mulching is the process of covering the soil with a layer of organic material to help retain moisture and suppress weeds. Fertilizing is the process of adding nutrients to soil to improve plant growth.

Chemical pollution, physical pollution, and radioactive pollution are all types of soil pollution. Biological pollution is not a type of soil pollution, but rather a type of water pollution that is caused by the presence of harmful microorganisms in water.

Phytoremediation is the process of using plants to remove contaminants from soil. Bioremediation is the process of using microorganisms to remove contaminants from soil. Excavation and landfilling are methods of removing contaminated soil from a site, but they do not involve the removal of contaminants from the soil itself.

Soil conservation practices, such as terracing, contour farming, and cover cropping, are designed to reduce soil erosion and improve water quality. They do not directly reduce the risk of flooding, which is primarily caused by excessive rainfall or snowmelt.