Nitrogen essential nutrient

Sodium is an indispensable element for some crops (notably sugar beet), can partially substitute for potassium in several crops, contributes to neutralising soil and subsoil acidity, and has a positive effect on soil phosphoms solubiUty. Sodium is an essential nutrient for cattle, and sodium appHcation to soil increases its content in pastures. Sodium nitrate is particularly effective as a nitrogen source for sugar beet, vegetable crops, tobacco, and cotton (qv), and for any crop in acid soils. 

Trace metals can serve as essential nutrients and as toxic substances (Sunda et al, 1991 Frausto da Silva and Williams, 1991). For example, cobalt is a component of vitamin B-12. This vitamin is essential for nitrogen fixing algae. In contrast, copper is toxic to marine phytoplankton at free ion concentrations similar to those found in seawater (Sunda and... 

The medium contains subsidiary nitrogen sources and additional essential nutrients such as calcium (added in the form of chalk to counter the natural acidity of the CSL), magnesium, sulphate, phosphate, potassium and trace metals. The medium is sterilized with steam at 120°C either in the fermenter itself or in ancilliary plant, which may be worked continuously. 

Molybdate, although present in small amounts in soil, is an essential nutrient for nitrogen fixation, specifically in the enzyme nitrogenase. It does not move readily through soil and is therefore considered to be of limited mobility. 

According to food composition tables, the diets used in the study provided an adequate intake of the essential nutrients. Each day, an exact amount of each food served the subjects was saved for analysis of nitrogen, calcium, and sulfur (as sulfate). The results for these elements agreed with those in the literature. These results indicated that during the soy diet, mean intakes were 78.5 g protein, 456 mg calcium, and 2305 mg. of sulfur. Intakes in the meat period were within 37o of those of the soy period. 

Biodegradation. The biological mineralization of fixed nitrogen is well studied ammonia is oxidized to nitrite, and nitrite to nitrate, by autotrophic bacteria, and nitrate is reduced to nitrogen by anaerobic bacteria. On the other hand, ammonia and nitrate are essential nutrients for plant and bacterial growth, so one option is to use these organisms to take up and use the contaminants. 

Plants need nitrogen, phosphorus and potassium for their growth. The soil is normally able to provide these nutrients to plants. When the same crops are grown over and over again, the soil loses these essential nutrients. Chemical fertilizers help to sustain or in some cases revive the fertility of the soil. 

The salt is produced in small amounts commercially in the United States, Israel, and Norway by the reaction of KCl with nitric acid. Though the salt is an attractive fertilizer material containing the two essential nutrients, nitrogen and potassium, in plant-available form, it is expensive to produce and thus enjoys only a limited market. 

We are concerned here with the enzymatic liberation of products that convert chemicals to less utilizable forms. The idea is to employ plant enzymes to strike directly at the insect s most critical needs, essential nutrients. In general, plant tissues are low in total nitrogen and pose a "nutritional hurdle" for insect herbivores (94). Plant proteins normally have low sulfhydryl and lysine content (95), which are nutritional requirements for insects (90,91). The nucleophilic properties of these limiting amino acids make them particularly susceptible to covalent binding by strongly electrophilic molecules such as o-quinones, hydroperoxides, ben-zoxazinones, and isothiocyanates formed in damaged plant tissues. 

A complete diet must supply the elements carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, and at least 18 other inorganic elements. The major elements are supplied in carbohydrates, lipids, and protein. In addition, at least 17 vitamins and water are necessary. If an essential nutrient is omitted from the diet, certain deficiency symptoms appear. 

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