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  2. Soil gas - Wikipedia

    en.wikipedia.org/wiki/Soil_gas

    Soil gases (soil atmosphere [1]) are the gases found in the air space between soil components. The spaces between the solid soil particles, if they do not contain water, are filled with air. The primary soil gases are nitrogen, carbon dioxide and oxygen. [2] Oxygen is critical because it allows for respiration of both plant roots and soil ...

  3. Soil respiration - Wikipedia

    en.wikipedia.org/wiki/Soil_respiration

    Soil respiration is a key ecosystem process that releases carbon from the soil in the form of carbon dioxide. Carbon is stored in the soil as organic matter and is respired by plants, bacteria, fungi and animals. When this respiration occurs below ground, it is considered soil respiration. Temperature, soil moisture and nitrogen all regulate ...

  4. Human impact on the nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Human_impact_on_the...

    Approximately 78% of Earth's atmosphere is N gas (N 2), which is an inert compound and biologically unavailable to most organisms.In order to be utilized in most biological processes, N 2 must be converted to reactive nitrogen (Nr), which includes inorganic reduced forms (NH 3 and NH 4 +), inorganic oxidized forms (NO, NO 2, HNO 3, N 2 O, and NO 3 −), and organic compounds (urea, amines, and ...

  5. Biological carbon fixation - Wikipedia

    en.wikipedia.org/wiki/Biological_carbon_fixation

    Biological carbon fixation, or сarbon assimilation, is the process by which living organisms convert inorganic carbon (particularly carbon dioxide, CO 2) to organic compounds. These organic compounds are then used to store energy and as structures for other biomolecules .

  6. Nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_cycle

    Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, ammonium (NH + 4), nitrite (NO − 2), nitrate (NO − 3), nitrous oxide (N 2 O), nitric oxide (NO) or inorganic nitrogen gas (N 2). Organic nitrogen may be in the form of a living organism, humus or in the intermediate products of organic ...

  7. Plant nutrients in soil - Wikipedia

    en.wikipedia.org/wiki/Plant_nutrients_in_soil

    Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...

  8. Gas blending - Wikipedia

    en.wikipedia.org/wiki/Gas_blending

    Carbon dioxide is also removed and to ensure that an appropriate amount of carbon dioxide remains, a mixture of nitrogen and carbon dioxide may be used for the sparging gas. [ 3 ] Purging and blanketing: The removal of oxygen from the headspace above the wine in a container by flushing with a similar gas mixture to that used for sparging is ...

  9. Birkeland–Eyde process - Wikipedia

    en.wikipedia.org/wiki/Birkeland–Eyde_process

    The same reaction is carried out by lightning, providing a natural source for converting atmospheric nitrogen to soluble nitrates. [12] + The hot nitric oxide is cooled and combines with atmospheric oxygen to produce nitrogen dioxide. The time this process takes depends on the concentration of NO in the air.