Sources of Nutrients for Plants

The main sources of elements in soils are the parent materials from which they are derived (Thornton, 1983). Nutrients may be naturally deficient in soils, and elements may be removed in crop and livestock products. Geochemical maps are helpful in the location of areas with deficiencies or excesses of particular elements (Webb et al., 1978 Potter, 1992). Atmospheric metals, whether present as precipitation, or in an enriched form of throughfall or stem flow, represent a more dilute source, available on a less regular basis. 

The biovailability of an element in the soil is the result of a competition between surface complexation at the plant root system, at various soil solid phases, and that remaining in solution. Organic and humic materials in soils act as ligands and the resulting complexes can be important in the movement of metal ions (Lindsay, 1974). At present there is little information on the relationship between concentration of the complexed species and their uptake rate by plants though some general evidence sug- 

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Energy source for microbes a source of nutrients for plant growth source of greenhouse gases... 

Calcium. Soil minerals are a main source of calcium for plants, thus nutrient deficiency of this element in plants is rare. Calcium, in the form of pulverized limestone [1317-65-3] or dolomite [17069-72-6] frequendy is appHed to acidic soils to counteract the acidity and thus improve crop growth. Such liming incidentally ensures an adequate supply of available calcium for plant nutrition. Although pH correction is important for agriculture, and liming agents often are sold by fertilizer distributors, this function is not one of fertilizer manufacture. 

Whitehouse et al [1985] describe the conditions peculiar to the development of a macrofouling community in power plants. Included are the continuous flow of seawater supplying oxygen and food and reduced salt deposition, the lack of competition from algae in the culverts and a reduction in the presence of predators. The waste products from marine life activity together with decomposition products from dead material, is a potential source of nutrients for microfouling. 

Organic mater is a source (short-term and long-term storage) of nutrients for plants and soil microbes. Organic matter often has a negative charge associated with the humus layer that attracts cations (which can be used as nutrients), metals, and pesticides. 

Biological properties Organic matter is a source of nutrients to plants, due to its cation-exchange capacity it provides metabolic energy for soil biological processes (e.g., bacterial) and contributes to ecosystem resilience, because it enhances the ecosystem s ability to recover from natural or anthropogenic perturbations. 

Methanol is a concentrated liquid source of carbon for plants, but only very low concentrations (usually less than 1% methanol) were previously utilized in laboratory studies, higher concentrations generally having been found to be toxic to plant tissues. As a carbon nutrient source for plants, application of 1% methanol to crops is not economically feasible, but if a method existed by which the... 

Glucose D-Glucose. A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. [NIH]... 

Borax decahydrate occurs in nature as mineral, borax (tincal). It is one of the most common sodium borate ores. The compound has several industrial applications. The refined material is mostly used in household cleaning products. It is used to make pyrex and other horosilicate glasses. Borax is added to fertilizers in small quantities as a source of boron, as a trace nutrient for plants. High purity grade borax is used in cosmetics, toilet products and electrolytic capacitors. It also is used in fire retardants, adhesives and herbicides. 

The immediate source of nutrient elements for plants is the soil solution but there is a paucity of information concerning its composition especially for micronutrients. A number of practical problems arise in studying the soil solution and the first is actually getting a sample of it. The soil solution can be removed for analysis by centrifugation or direct suction. Some workers prefer a saturation extract , when the soil is allowed to equilibrate with water which is then extracted by mild suction. The solutions extracted by these techniques are very dilute and consequently not stable chemically. They present considerable analytical problems although these have eased in recent years now that very sensitive flameless atomic absorption methods have become widely available. 

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