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REMOBILIZING OF PLANT NUTRIENTS. By soil Group 1 Penny, Nash and Brandi. WHAT IS REMOBLIZING?.
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REMOBILIZING OF PLANT NUTRIENTS By soil Group 1 Penny, Nash and Brandi
WHAT IS REMOBLIZING? Nutrients are moved inside a plant to where they are most needed. For example, a plant will try to supply more nutrients to its younger leaves than its older ones. So when nutrients are mobile, the lack of nutrients is first visible on older leaves. However, not all nutrients are equally mobile. When a less mobile nutrient is lacking, the younger leaves suffer because the nutrient does not move up to them but stays lower in the older leaves. Nitrogen, phosphorus, and potassium are mobile nutrients, while the others have varying degrees of mobility.
NITROGEN Nitrogen, more than any other elements, promotes rapid growth and dark green color. Plants need a lot of nitrogen because it is part of many important compounds, including protein and chlorophyll. Plants respond to nitrogen in the following ways:
HOW PLANTS USES NITROGEN • Nitrogen speeds growth. • Plants make large amounts of chlorophyll, a dark green pigment. • Protein content of plant tissue will be at its best. • Plants use water best when they have ample nitrogen.
TOO MUCH NITROGEN IN PLANTS CAUSES: • Soft, weak, easily injured growth is encouraged. • More prone to some diseases and insects. • Slows maturity and ripening of many crops. • Delays the hardening-off process that protects many plants from winter cold. • Impairs flavor in several vegetable crops. • Possible health effects for animal and people consuming them.
In general, nitrogen promotes vegetative growth-stems, leaves and roots-more than the reproductive growth of flowers, and fruits.
THE NITROGEN CYCLE Organisms require nitrogen to produce amino acids. Nitrogen makes up seventy-eight percent of the atmosphere, but most organisms can not use this form of nitrogen, and must have the fixed form. The nitrogen cycle produces the fixed form of nitrogen these organisms need.
THE NITROGEN CYCLE Step 1: A special type of bacteria called nitrogen fixing bacteria take in atmospheric nitrogen and produce ammonia (NH3). Step 2: Other bacteria use this ammonia to produce nitrates and nitrites, which are nitrogen and oxygen containing compounds. Step 3: The nitrates and nitrites are used by plants to make amino acids which are then used to make plant proteins. Step 4: Plants are consumed by other organisms which use the plant amino acids to make their own. Step 5: Decomposers convert the nitrogen found in other organisms into ammonia and return it to the soil. A few of these type of bacteria return nitrogen to the atmosphere by a process called denitrification, however this amount is small.
PHOSPHORUS Phosphorus also spurs growth but to a lesser extent than nitrogen. Phosphorus affects plant growth in a number of ways.
HOW PLANTS USES PHOSPHORUS • Is part of genetic material and so it is involved in plant reproduction and cell division. • Part of the chemical that stores and transfers energy in all living things. • Spurs early and rapid root growth and helps a young plant develop its roots. • Helps plants use water more efficiently by improving water uptake by roots.
HOW PLANTS USES PHOSPHORUS • Helps plant resist cold and disease, speeds crop maturity, aids blooming and fruiting, and improves the quality of grains and fruits. • Improves the efficiency of nitrogen uptake by plants, making better use of fertilizers. • Ensures that animal feeds will supply sufficient phosphorus.
In general phosphorus acts to balance nitrogen. While nitrogen delays maturity, phosphorus hasten it. Nitrogen aids vegetative growth; phosphorus aids blooming and fruiting. Phosphorus is most important for crops from which we use the floral parts-flowers, fruits, or seeds.
THE PHOSPHORUS CYCLE • Biological importance:Phosphorus is a component of nucleic acids, phospholipids, as well as bones and teeth. • Forms available to life: Inorganic phosphate (PO43-) is absorbed by plants. • Reservoirs: The largest reservoirs are in sedimentary rocks. • Key processes:Weathering of rocks adds phosphorus to soil; some leaches into groundwater and soil and find its way to sea. • Phosphate taken up by producers cycle through the food web via consumers.
POTASSIUM (POTASH) Potassium is a key plant nutrient. Plants consume more potassium than any other except nitrogen. Potassium actives enzymes needed in formation of protein, starch, cellulose and lignin. Necessary for the development of thick cell walls and strong, rigid plant stems. Potassium regulates the opening and closing of leaf stoma. Therefore potassium is involved in the gas exchange needed for photosynthesis and in transpiration.
Potassium is instrumental in moving sugars produces by photosynthesis within the plant, so it is important in the development and ripening of the fruits. Potassium is needed for proper growth of root and tuber crops.
HOW PLANTS USES POTASSIUM • Plants have strong stems. • Fights diseases. • Makes plants more winter-hardy and less injured by spring or fall frosts. • Regulating the stoma, influences the transpiration rate, transpires less and makes better use of the water supplies.
Potassium (K) is everywhere in nature. It can be found in oceans and seas, in the soil, in rocks and minerals, and in plants and animals. It is essential to all forms of life…human, animal and plant. Plants grown for food take up and use large quantities of K. Potassium is one of the three ‘primary’ plant nutrients, along with nitrogen (N) and P, needed in large amounts by plants.
CHLORINE The function of chlorine, a recently identified essential element, is not well understood. It is known to play a role in photosynthesis and may help regulate opening and closing of the stomata. Chlorine is needed in very small amount and is commonly found in the soil.
THE CHLORINE CYCLE The natural chlorine cycle with transformation processes of inorganic Cl- depicted in yellow and organically bound chlorine in green.
OH IS HYDROXYL RADICAL • The hydroxyl radical (OH) is the primary cleansing agent of the lower atmosphere, providing the dominant sink for many greenhouse gases (e.g., CH4, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons) and pollutants (e.g., CO, non-methane hydrocarbons).
MAGNESIIUM Magnesium resembles calcium chemically and in its action in soil. Its role in the plant differs, however. Magnesium is the essential ingredients in chlorophyll-each molecule has one magnesium atom at its center. Magnesium also aids the uptake of other elements, especially phosphorus. Magnesium is involved in protein carbohydrates, and fat synthesis, as well as a wide range of other compounds.
MOLYBDENUM Molybdenum, the nutrient with the smallest plant requirement except nickel, is necessary for proper nitrogen metabolism by plants and for nitrogen fixation gathers in soil organic matter. Molybdenum is most available at a high soil pH. Shortage is most common on acid, leached, and low-organic-matter coarse soils. An ounce of a soluble molybdenum material, often mixed with phosphate fertilizer, will usually treat an acre of deficient soil. Frequently, liming releases enough of this trace elements to cure shortages.
The next time you stand on the soil, think about the billions of organisms at work beneath you. They are part of a cycle that returns valuable nutrients to the soil. Without these unseen creatures, the plants we depend on for food could not grow, and the life sustaining cycle on earth would be broken.
