Primary nutrients

For the year ended June 30, 1990, about 39% of the total primary nutrient used in the United States was apphed in mixtures, whereas the remaining 61% was apphed by direct apphcation. Breakdown by plant nutrient is shown in Table 11. High usage of anhydrous ammonia and nitrogen solutions (Fig. 

Secondary and Micronutrients in Fertilizers The great majority of farm fertilizers are produced, marketed, and appHed with regard only to the primary plant nutrient content. The natural supply of secondary and micronutrients in the majority of soils is usually sufficient for optimum growth of most principal crops. There are, however, many identified geographical areas and crop—soil combinations for which soil appHcation of secondary and/or micronutrient sources is beneficial or even essential. The fertilizer industry accepts the responsibiHty for providing these secondary and micronutrients, most often as an additive or adjunct to primary nutrient fertilizers. However, the source chemicals used to provide the secondary and micronutrient elements are usually procured from outside the fertilizer industry, for example from mineral processors. The responsibiHties of the fertilizer producer include procurement of an acceptable source material and incorporation in a manner that does not decrease the chemical or physical acceptabiHty of the fertilizer product and provides uniform appHcation of the added elements on the field. 

Some commonly used primary nutrient fertilizers are incidentally also rich sources of calcium. Ordinary superphosphate contains monocalcium phosphate and gypsum in amounts equivalent to all of the calcium originally present in the phosphate rock. Triple superphosphate contains soluble monocalcium phosphate equivalent to essentially all the P2 5 product. Other fertilizers rich in calcium are calcium nitrate [10124-37-5] calcium ammonium nitrate [39368-85-9] and calcium cyanamide [156-62-7]. The popular ammonium phosphate-based fertilizers are essentially devoid of calcium, but, in view of the natural calcium content of soils, this does not appear to be a problem. 

Analysis grade refers to the primary nutrient content of a fertilizer. Nitrogen content is expressed as % elemental N. Phosphoms content is expressed as % P2O5, and potassium as % K2O, given in the order N—P—K. 

Traditional agriculture considers only those substances containing one or more of the three primary nutrierrts as fertilizers. Mat comparries sell rrrixtures of the above substance designed to contain all three of the primary nutrients, i.e., designed to be complete... 

This chapter is concerned with the three primary nutrients making up most fertilizers nitrogen, phosphorus, and potassium. The usual sources of nitrogen are ammonia, ammonium nitrate, urea, and ammonium sulfate. Phosphorus is obtained from phosphoric acid or phosphate rock. Potassium chloride is mined or obtained from brine and the sulfate is mined in small amounts. Potassium nitrate is made synthetically. These chemicals have already been described under inorganic chemicals of the top 50. Sources for the three primary nutrients are given in Fig. 21.1. 

Fertilizers may contain all three primary nutrients, in which case they are called mixed fertilizers, or they may contain only one active ingredient, called direct application fertilizers. Recently the ratio of direct application to mixed fertilizers is 60 40 in the U.S. Nitrogen and potash are consumed mainly from direct application fertilizers. Phosphate is applied mostly from mixed fertilizers. 

Primary nutrients or elements Secondary nutrients or elements... 

Nomenclature. Because the ammonium phosphate fertilizers contain two of the primary plant nutrients, il is pertinent at tilts point lo briefly continent on the manner in which these fertilizers are named. A series of three numbers, separated by dashes, is used lo indicate the primary nutrient content uf fertilizer mixtures. In order, from left lo right, the numbers show the percentage of nitrogen, phosphoric oxide, and potash ... 

Antony, A., Sripriya, G., and Chandra, T. S. (1996). Effect of fermentation on the primary nutrients in finger millet (Eleusine coracana). ]. Agric. Food Chem. 44, 2616-2618. 

Usually, three numbers are used when giving the grade of a fertilizer product, and these three numbers always refer in order to the content of the primary nutrients nitrogen, phosphorus, and potassium. If other nutrients are present, their content can also be indicated in the grade of the fertilizer product each extra number is followed by the chemical symbol of the nutrient it represents. Many countries indicate the content of phosphorus and potassium not in the elemental form but in the oxide form, P205 and K20. Thus, a fertilizer product with a grade of... 

Nitrogen is a component of amino acids that make up proteins chlorophyll (the molecule that captures the sun s energy) enzymes and the genetic material, nucleic acids. Therefore, this nutrient is required in large amounts by all plants and forms one of three primary nutrients. Although nitrogen is available in abundance... 

Potassium is essential to both plant and animal life. It is one of the three primary nutrients, or macronutrients, required by plants. Plants require relatively large amounts of potassium in order to grow and remain healthy. 

There are three primary nutrients - Nitrogen (N), Phosphorus (P), and Potassium (K) - listed on the front of most fertilizers. The letters "N," "P," and K" will be followed by a number that represents the designated amount of each primary nutrient in the package. For example, if a container of fertilizer lists "N-2, P-6, K-1," that means the nutrients are proportionally 2% nitrogen, 6% phosphorus, and 1% potassium (or potash). 

NPK - three primary nutrient indicators found on the label of most nutrients... 

Pollen the male genetic bearing micro-pore Potassium - primary nutrient... 

Because apparent metabolic yields can be determined without knowledge of n, Y values can be monitored to detect changes in metabohc patterns of cells in immobilized-cell bioreactors. For example, yj[ac,gic is easy to obtain and provides a good measure of the fate of the primary nutrient glucose. Relatively constant values for F[ac,gic NH3,gic Oz.gic other )delds provide a good indication of a stable culture environment. Under these conditions. Equation 4.2.44 may be used with confidence to estimate changes in the viable cell density. 

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