Chapter 31
Soil and Plant Nutrition
By Boundless
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Plants meet their nutritional needs for growth by absorbing soil nutrients, water, and carbon dioxide, in addition to the required sunlight.
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Plants are composed of water, carbon-containing organics, and non-carbon-containing inorganic substances such as potassium and nitrogen.
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Approximately 20 macronutrients and micronutrients are deemed essential nutrients to support all the biochemical needs of plants.
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Soil is a mix of varying amounts of inorganic matter, organic matter, water, and air.
Soil formation is the result of a combination of five factors: parent material, climate, topography, biological factors, and time.
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Soils are made up of combinations of four distinct layer types or horizons: O horizon, A horizon, B horizon, and C horizon.
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Plants cannot extract the necessary nitrogen from soil, so they form symbiotic relationships with rhizobia that can fix it as ammonia.
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Many plants form associations called mycorrhizae with fungi that give them access to nutrients in the soil, protecting against disease and toxicities.
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Many species of plants are unable to make their food via photosynthesis and must acquire nutrients in a variety of additional ways.