Phosphorus. Cycle. Meghan Ketchie, Jasmyn Lowe, Chloe Johnson, and. Logan Baker. PDF | The chapter on the phosphorous (P) cycle of Lake Kinneret presents an overview of more than 40 years of research and monitoring while. PDF | On Jan 1, , Gabriel M. Filippelli and others published Phosphorus Cycle.

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    Phosphorus Cycle Pdf

    The Global Phosphorus Cycle. Gabriel M. Filippelli. Department of Geology. Indiana University - Purdue University Indianapolis. West Michigan Street. IMPORTANCE OF PHOSPHORUS—WHY P? Nature apparently made an odd choice when it chose to build most of the critical photosynthesis and metabolic. Phosphorus Basics – The Phosphorus Cycle. Agronomy Fact Sheet Series. Department of Crop and Soil Sciences. 1. College of Agriculture and Life Sciences.

    Protein synthesis The Phosphorus Cycle In contrast to nitrogen, the atmosphere does not provide phosphorus. However, the phosphorus cycle is by no means less complex than the nitrogen cycle, and there are many factors that affect the availability of phosphorus in the soil. The diagram below is an illustration of the phosphorus cycle. Figure A representation of the phosphorus cycle. Phosphorus Uptake by Plant Roots Plant roots absorb phosphorus from the soil solution.

    These particles are commonly found in many of the most highly weathered soils and high weathered volcanic soils of Hawaii. Since P-sorption results in a decrease of plant available phosphorus, P-sorption can become a major issue in many Hawaii soils.

    Additionally, in calcareous soils P-sorption may occur as phosphates sorb to impurities such as aluminum and iron hydroxides or displace carbonates in calcium carbonate minerals.

    Soil Management

    Volcanic soils tend to have the greatest P-sorption of all soils since volcanic soils contain large amounts of amorphous material. Following volcanic soils, highly weathered soils such as Oxisols and Ultisols have the next greatest P-sorption capacities. This is due to the presence of large amounts of aluminum and iron oxides and highly weathered kaolin clays.

    On the other end of the spectrum, less weathered soils and organic soils have low P-sorption capacities. Amount of clay: As the amount of clay increases in the soil, the P-sorption capacity increases as well.

    This is because clay particles have a tremendous amount of surface area for which phosphate sorption can take place.

    In fact, a soil binds twice the amount of phosphorus under acidic conditions, and these bonds are five times stronger. Temperature: Generally, P-sorption increases as temperature increases. Factors that decrease P-sorption: Other anions, such as silicates, carbonates, sulfates, arsenate, and molybdate, compete with phosphate for a position on the anion exchange site. As a result, these anions can cause the displacement, or desorption, of phosphate from the soil exchange site.

    Desorption causes phosphate availability in the soil solution to increase. Organic matter increases P availability in four ways. First, organic matter forms complexes with organic phosphate which increases phosphate uptake by plants. Second, organic anions can also displace sorbed phosphate.

    Third, humus coats aluminum and iron oxides, which reduces P sorption. Finally, organic matter is also a source of phosphorus through mineralization reactions. Flooding the soil reduces P-sorption by increasing the solubility of phosphates that are bound to aluminum and iron oxides and amorphous minerals.

    Phosphate Precipitation and Dissolution Phosphate precipitation is a process in which phosphorus reacts with another substance to form a solid mineral. In contrast, dissolution of phosphate minerals occurs when the mineral dissolves and releases phosphorus. Precipitation and dissolution reactions greatly influence the availability of phosphate in the soil. Phosphate minerals can dissolve over time to replenish the phosphate in the soil solution.

    This reaction increases the availability of phosphorus. On the other hand, phosphate minerals form by removing phosphate from soil solution. This reaction decreases the availability of phosphorus. However, both precipitation and dissolution are very slow processes. Solubility of Phosphate Minerals The solubility of phosphate minerals is very dependent upon soil pH.

    The soil pH for optimum phosphorus availability is 6. Under acidic conditions, phosphorus may react with aluminum and iron to form minerals, such as strengite and varescite. Thus, soil organic phosphorus is a very important aspect of the P cycle. The various sources of organic phosphorus include Phytin Phospholipids Like nitrogen, organic phosphorus is converted to inorganic phosphate through the process of mineralization. The immobilization of inorganic phosphate, in contrast, is the reverse reaction of mineralization.


    Eutrophication is an enrichment of water by nutrient that lead to structural changes to the aquatic ecosystem such as algae bloom, deoxygenation, reduction of fish species.

    The primary source that contributes to the eutrophication is considered as nitrogen and phosphorus.

    When these two elements exceed the capacity of the water body, eutrophication occurs. Phosphorus that enters lakes will accumulate in the sediments and the biosphere, it also can be recycled from the sediments and the water system. When eroded soil enters the lake, both phosphorus and the nitrogen in the soil contribute to eutrophication, and erosion caused by deforestation which also results from uncontrolled planning and urbanization.

    Wetlands are frequently applied to solve the issue of eutrophication. Nitrate is transformed in wetlands to free nitrogen and discharged to the air. Phosphorus is adsorbed by wetland soils which are taken up by the plants. Therefore, wetlands could help to reduce the concentration of nitrogen and phosphorus to remit and solve the eutrophication.

    However, wetland soils can only hold a limited amount of phosphorus. To remove phosphorus continually, it is necessary to add more new soils within the wetland from remnant plant stems, leaves, root debris, and undecomposable parts of dead algae, bacteria, fungi, and invertebrates.

    Nutrients are important to the growth and survival of living organisms, and hence, are essential for development and maintenance of healthy ecosystems.

    Humans have greatly influenced the phosphorus cycle by mining phosphorus, converting it to fertilizer, and by shipping fertilizer and products around the globe. Transporting phosphorus in food from farms to cities has made a major change in the global Phosphorus cycle.

    However, excessive amounts of nutrients, particularly phosphorus and nitrogen, are detrimental to aquatic ecosystems.

    Waters are enriched in phosphorus from farms' run-off, and from effluent that is inadequately treated before it is discharged to waters. The input of P in agricultural runoff can accelerate the eutrophication of P-sensitive surface waters.

    Cultural or anthropogenic eutrophication, however, is water pollution caused by excessive plant nutrients; this results in excessive growth in the algal population; when this algae dies its putrefaction depletes the water of oxygen. Such eutrophication may also give rise to toxic algal bloom.

    Both these effects cause animal and plant death rates to increase as the plants take in poisonous water while the animals drink the poisoned water.

    Surface and subsurface runoff and erosion from high-phosphorus soils may be major contributing factors to this fresh water eutrophication. The processes controlling soil Phosphorus release to surface runoff and to subsurface flow are a complex interaction between the type of phosphorus input, soil type and management, and transport processes depending on hydrological conditions.

    Repeated application of liquid hog manure in excess to crop needs can have detrimental effects on soil phosphorus status. Also, application of biosolids may increase available phosphorus in soil. This causes a sharp increase in phosphorus concentration in solution and phosphorus can be leached. In addition, reduction of the soil causes a shift in phosphorus from resilient to more labile forms.

    This could eventually increase the potential for phosphorus loss. This is of particular concern for the environmentally sound management of such areas, where disposal of agricultural wastes has already become a problem. It is suggested that the water regime of soils that are to be used for organic wastes disposal is taken into account in the preparation of waste management regulations.

    Human interference in the phosphorus cycle occurs by overuse or careless use of phosphorus fertilizers. This results in increased amounts of phosphorus as pollutants in bodies of water resulting in eutrophication. Eutrophication devastates water ecosystems by inducing anoxic conditions. From Wikipedia, the free encyclopedia. Organic phosphorus in the environment. CABI Publishing.

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    Phosphorus cycle

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