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| | Biological Nitrogen Fixation |
 | | Nitrogen fixation is characteristically higher in environments such as tropical soils, where such factors as substrate availability, temperature and moisture are more favorable to the maintenance and activity of a high bacterial population. | | | This replacement of soil nitrogen is generally accomplished by the addition of chemically fixed nitrogen in the form of commercial inorganic fertilizers or by the activity of biological nitrogen fixation (BNF) systems. | | | The nitrogen fixing activity of free-living, non-photosynthetic, aerobic bacteria is strongly dependent on favorable moisture conditions, oxygen, and an organic food source. |
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http://edis.ifas.ufl.edu/SS180
(2181 words)
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| | Biological Nitrogen Fixation |
| | Estimates of nitrogen fixation by food legumes range from 0 to 300+ kg N/ha/year. | | | In general terms, the less nitrogen available in the soil and the lower the nitrogen- harvest index of the legume crop, the greater will be the nitrogen gain by the system. | | | Assessments of nitrogen fixation by woody legumes are particularly needed. |
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http://www.nap.edu/readingroom/books/bnf/chapter1.html
(9967 words)
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| | Biological Nitrogen Fixation |
| | Nitrogen is the soil nutrient element needed in greatest quantity by crops. | | | Whatever type of fertilizer nitrogen is applied, microbial action converts it to nitrate, a mobile form that is assimilated by plants and is subject to loss from surface-water movement, thereby polluting streams and rivers and eventually affecting estuarine and marine ecosystems. | | | Of the fertilizer nitrogen applied to a crop, seldom is more than 50 percent assimilated, and often the efficiency of utilization is much less. |
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http://www.nap.edu/readingroom/books/bnf/summary.html
(1254 words)
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| | Nitrogen Fixation by Legumes |
| | Nitrogen fertilizer is applied at planting to these legumes when grown on sandy or low organic matter soils to supply nitrogen to the plant before nitrogen fixation starts. | | | However, nitrogen fixation by legumes can be in the range of 25-75 pounds of nitrogen per acre per year in a natural ecosystem, and several hundred pounds in a cropping system. | | | Measurement of nitrogen fixation in the field is difficult. |
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http://www.csun.edu/~hcbio027/biotechnology/lec10/lindemann.html
(1628 words)
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| | LEGUME NITROGEN FIXATION AND TRANSFER |
| | The primary pathways for nitrogen transfer from the legume to the soil are through grazing livestock and decomposition of dead legume plant material. | | | Nitrogen is the most limiting nutrient for plant growth. | | | Factors that influence the quantity of nitrogen fixed are the level of soil nitrogen, the rhizobia strain infecting the legume, amount of legume plant growth, how the legume is managed, and length of growing season. |
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http://overton.tamu.edu/clover/cool/nfix.htm
(1520 words)
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| | The Overstory #65--Biological Nitrogen Fixation |
| | Nitrogen Fixation for Tropical Agricultural Legumes (NifTAL) and Food and Agriculture Organization of the United Nations. | | | Nitrogen is commonly the most limiting element in agricultural production, and one of the most expensive to purchase as fertilizer (NifTAL 1984). | | | Legume Inoculants and Their Use (1994) by Nitrogen Fixation for Tropical Agricultural Legumes (NifTAL) and Food and Agriculture Organization of the United Nations is an excellent guide for Rhizobium technology for practitioners. |
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http://www.agroforestry.net/overstory/overstory65.html
(1479 words)
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| | Botany online: Interactions of Plants and Bacteria — Nitrogen Fixation |
| | Nitrogen fixation has been thoroughly covered during the last years, since genetic engineering fosters the hope for techniques improving the nitrogen supply of plants. | | | Although extremely important, the contribution of symbiotic bacteria to the nitrogen supply of plants is very small when seen in relation to nature’s total nitrogen budget. | | | The production of synthetic nitrogen fertiliser is expensive and extraordinarily costly in terms of energy. |
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http://www.biologie.uni-hamburg.de/b-online/e34/34b.htm
(1839 words)
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| | Nitrogen: The Essential Element |
| | Nitrogen is likely to be in short supply for crop production unless supplemented by legume crop residues or by the application of fertilizers, manures, or other high-nitrogen materials. | | | Three types of inputs can compensate for nitrogen losses in farm fields: (1) fertilization, (2) nitrogen fixation by legumes, and (3) supplementation with manure or other organic matter high in nitrogen. | | | Estimate the amount of nitrogen that will be supplied by the mineralization of soil organic nitrogen and crop residues. |
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http://pmep.cce.cornell.edu/facts-slides-self/facts/nit-el-grw89.html
(2457 words)
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| | s9chap2 |
| | Symbiotic nitrogen fixers are associated with plants and provide the plant with nitrogen in exchange for the plant's carbon and a protected home. | | | Nitrogen fixation research will undoubtedly make important contributions to agriculture by substituting traditional fertilizer N inputs (which are costly, polluting and time consuming), with a cheap natural biological alternative. | | | Nitrogen is a primary nutrient for all green plants, but it must be modified before it can be readily utilized by most living systems. |
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http://www.soils.umn.edu/academics/classes/soil2125/doc/s9chap2.htm
(1973 words)
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| | History of ChEn: Nitrogen |
| | Fixed nitrogen is also returned to the soil when plants and animals die. | | | When the war was over, fixed nitrogen continued to be produced in large amounts because of its use as a fertilizer. | | | Animals gain access to this nitrogen by eating the plants, and deposit excess nitrogen in their feces. |
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http://www.pafko.com/history/h_s_n2.html
(1055 words)
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| | Amines - Cambridge University Press |
| | Competing with fertilizers for the world supply of fixed nitrogen were the dyestuffs industry and, after the discovery of dynamite in 1866, the emerging explosives industry. | | | However, when the soil is planted with legumes, clover or alfalfa this figure rises to 250 kg of nitrogen per year. | | | Animals are able to obtain fixed nitrogen either by eating plants (herbivores) or by eating other animals (carnivores). |
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http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=0521782848&ss=exc
(3300 words)
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| | Nitrogen Fixation |
| | Nitrogen is essential for plant and animal growth. | | | Studies in areas from the arctic tundra to the equator have shown that lichens are important nitrogen sources in most ecosystems but the hornwort inputs to ecosystems have been less well studied. | | | Once in the lichen or hornwort, the nitrogen can become available to plants and animals in several ways: |
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http://www.anbg.gov.au/cryptogams/underworld/panel-12
(385 words)
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| | Nitrogen fixation |
| | However, these bacteria can make only a small contribution to the nitrogen nutrition of the plant, because nitrogen-fixation is an energy-expensive process, and large amounts of organic nutrients are not continuously available to microbes in the rhizosphere. | | | So, nitrogen is often the limiting factor for growth and biomass production in all environments where there is suitable climate and availability of water to support life. | | | In this way, valuable nitrogen can be lost from the soil, reducing the soil fertility. |
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http://helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm
(2449 words)
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| | Part I. The range of organisms that can fix nitrogen |
| | Azolla is found worldwide and is sometimes used as a valuable source of nitrogen for agriculture. | | | In this case the host plant is the palm Welfia regia, a common understory plant in the tropical rainforests around the La Selva field station which is operated by the Organization for Tropical Studies in Costa Rica. | | | Many, but not all, are capable of nitrogen fixation. |
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http://academic.reed.edu/biology/Nitrogen/Nfix1.html
(830 words)
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| | Waterose Lab: The Nitrogen Cycle: Isolation of Rhizobium and Azotobacter by Bacterial Cell Gram Stain |
| | The only type of visible colony was a large mass of white slime that covered 30% of the plate, with large areas of run-on colonies and some single colonies of the same morphology. | | | The growing media of the mannitol N-free agar plate is selective in that it is nitrogen free and uses mannitol as the carbon source. | | | The microbe associated with clover soil is the Rhizobium which is characteristically known as a nitrogen fixer. |
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http://www.geocities.com/Waterose_Test/labs15.html
(3947 words)
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| | Lab Manual Exercise # 1 |
| | Nitrogen fixation, nitrification, and ammonification make nitrogen available to autotrophic plants and ultimately to all members of the ecosystem. | | | Luckily for plants and animals on the earth, natural nitrogen fixation exceeds denitrification. | | | However, the serious problem today is that humans have greatly accelerated nitrogen fixation by the tremendous production of chemical fertilizers. |
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http://waynesword.palomar.edu/lmexer1.htm
(7365 words)
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| | 5th European Nitrogen Fixation Conference |
| | Nitrogen availability in agricultural soils is frequently the limiting factor for crop productivity. | | | Nitrogen Fixation in agriculture and the environment: complementary research between the EU and Developing countries (joint with ENFC sessions 4, 8 and 11) | | | The Fifth European Nitrogen Fixation Conference is designed to enhance European collaboration in the field of Nitrogen Fixation research and to foster collaborations between European scientists and those in developing countries. |
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http://www.jic.bbsrc.ac.uk/events/nitfix
(3601 words)
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| | nitrogen fixation books |
| | Nitrogen Fixation in Agriculture, Forestry, Ecology, and the Environment | | | Biological Fixation of Nitrogen for Ecology and Sustainable Agriculture | | | Biological Nitrogen Fixation, Sustainable Agriculture and the Environment |
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http://www.cplbookshop.com/glossary/G249.htm
(288 words)
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| | Nitrogen Fixation and Inoculation of Forage Legumes |
| | If a particular legume has not been grown in a field for several years, inoculation of seed is generally recommended as "insurance" to ascertain maximum benefit from legume N fixation. | | | Legumes are plants, like peas, beans, soybean, alfalfa, clover, and aeschynomene, that have special bacteria in their rooting system and make use of N from the air. | | | Approximately 110 million tons of N are required for the world's annual food production but only 7 million tons are supplied by the fertilizer industry; the rest come from legumes. |
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http://edis.ifas.ufl.edu/BODY_AG152
(1799 words)
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| | [No title] |
| | The presence of a good nitrogen source represses the use of a poor nitrogen source. | | | Rhizobium is also found free in the soil but only fixes N2 when inside the root nodules of its host plant, in a strictly controlled microaerophilic environment. | | | ÐÏࡱá > þÿ þÿÿÿ ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿì¥Á @ ø¿ 3D jbjbîî ‘ á á 6 ÿÿ ÿÿ ÿÿ l Ö Ö Ö Ö 8 4 B 4 Ö ý , * , , , , , , , ) I x X ¥ X ” ” ” ” ô * ” ^ x ^ * ” z ” v eà’¹ Ö Ö ” ý ý Á ” Á ” à å NITROGEN FIXATION Nitrogen fixation is limited to prokaryotes. |
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http://www.science.siu.edu/microbiology/Micr425/NitrogenFix02
(1975 words)
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| | Plant hemoglobins: Oxygen handlers critical for nitrogen fixation |
| | Symbiotic nitrogen fixation is important for sustainable agriculture and contributes millions of tons of reduced nitrogen to crops and pastures each year. | | | The most conspicuous plant hemoglobins are the symbiotic hemoglobins of legumes; these hemoglobins accumulate in root nodules and give these specialized organs their distinctive red color. | | | Thus, plant hemoglobins fulfill roles analogous to those of animal hemoglobins, as well as novel roles that are apparently unique to symbiotic nitrogen fixation. |
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http://www.eurekalert.org/pub_releases/2005-03/cp-pho032305.php
(431 words)
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| | Zehr Research |
| | In the case of nitrogen, nitrogen sources are primarily the flux of nitrate from nutrient-rich deep water across the nutricline and thermocline, and the recycling of nitrogen from excretion of waste my microzooplankton, zooplankton and larger animals. | | | The biological productivity of the oceans is dependent upon the availability of nutrients, such as nitrogen, phosphorus, iron, etc. These nutrients are necessary to support the growth of microalgae and microorganisms that are the basis of marine food chains. | | | Ammonium is readily used by most organisms, but atmospheric dinitrogen is only a source of nitrogen for organisms with the capability for nitrogen fixation. |
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http://ic.ucsc.edu/~zehrj/ocea80a/zehrresearch2.html
(411 words)
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| | Glossary of Terms: N |
| | Over abundance of nitrogen in natural ecosystems because of human induced inputs related to agriculture and fossil fuel combustion. | | | Form of nitrogen commonly found in the soil. | | | Nitrogen dioxide is a component in the production of photochemical smog. |
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http://www.physicalgeography.net/physgeoglos/n.html
(1335 words)
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| | NITROGEN FIXATION |
| | Nitrogen as a Plant Nutrient (sse previous lectures too !) | | | Most N transformations in soil are carried out by microorganisms. | | | Nitrate is the predominant form of N taken up by crop plants (exception is rice; NH The enzymes involved are nitrate reductase and nitrite reductase |
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http://jan.ucc.nau.edu/~gaud/bio326/class/ecosyst/Ncycling2.html
(787 words)
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| | Nitrogen Fixation |
| | Because of the specificity of the interaction between the Nod factor and the receptor on the legume, some strains of rhizobia will infect only peas, some only clover, some only alfalfa, etc. The treating of legume seeds with the proper strain of rhizobia is a routine agricultural practice. | | | Perhaps the environment provided by their host, e.g., lots of food and just the right amount of oxygen, enabled the rhizobia to do the job more efficiently than before. | | | Symbiotic nitrogen fixation occurs in plants that harbor nitrogen-fixing bacteria within their tissues. |
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http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NitrogenFixation.html
(845 words)
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| | Untitled Document |
| | fixation in your plant in terms of µmol N | | | They are able to make large amounts of the nitrogen in the air available to plants through this activity. | | | One of the most important macro-nutrients, one that is frequently in short supply, is nitrogen. |
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http://web.grinnell.edu/courses/bio/qubitmanual/Labs/Nitrogen/NitrogenFixationLab.html
(2080 words)
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| | Single-Celled Life Boosting Ocean Nitrogen Levels, Scientists Say |
| | Carbon dioxide is one of the naturally occurring gases that traps energy from the sun and helps maintain hospitable temperatures on Earth, creating the "greenhouse effect." But studies indicate that greenhouse gases that form from vehicle and industrial emissions are enhancing the greenhouse effect and contributing to global climate warming. | | | These 'unicells' are the largest single source of nitrogen entering the water in broad areas of the ocean." | | | Carbon dioxide, a major element of the carbon cycle, is one of the naturally occurring gases that traps energy from the sun and helps maintain hospitable temperatures on Earth, creating the greenhouse effect. |
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http://usinfo.state.gov/xarchives/display.html?p=washfile-english&y=2004&m=August&x=20040830140710lcnirellep0.2484857&t=livefeeds/wf-latest.html
(1069 words)
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| | Life History and Ecology of Cyanobacteria |
| | The ferns then provide an inexpensive natural fertilizer and nitrogen source for the rice plants when they die at the end of the season. | | | Fertilizers work the way they do in part because they contain additional fixed nitrogen which plants can then absorb throough their roots. | | | Nitrification cannot occur in the presence of oxygen, so nitrogen is fixed in specialized cells called heterocysts. |
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http://www.ucmp.berkeley.edu/bacteria/cyanolh.html
(550 words)
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| | Kahn |
| | My laboratory is interested in the metabolic coupling between the rhizobia and its host. | | | Increases understanding of symbiotic metabolism could make a substantial contribution to plant productivity. | | | Research interest: symbiotic nitrogen fixation; plant-bacterial interactions; bacterial genetics. |
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http://www.sci.wsu.edu/mbio/Kahn
(257 words)
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| | Nitrogen fixation - EvoWiki |
| | Nitrogen fixing bacteria belonging to genera such as Rhizobium, Bradyrhizobium, etc. are commonly found in root nodules on plants (mostly legumes), and some crops are grown only because the high levels of nitrogen compounds produced in the roots. | | | Electrons flow from ferredoxin to the reductase (iron protein, or Fe protein) to nitrogenase (molybdenum-iron protein, or MoFe protein) to reduce nitrogen to ammonia. | | | The enzymes that carry out the reduction of nitrogen are known in the literature as nitrogenases. |
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http://wiki.cotch.net/index.php/Nitrogen_fixation
(2183 words)
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| | Nitrogen Flow |
| | In nature, there are two main ways of "fixing" nitrogen: | | | SECOND WAY: Special microorganisms living mostly in soil and water. | | | Though about 78% of the Earth's atmosphere is nitrogen, plants and animals don't necessarily have an easy time getting all the nitrogen they need. |
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http://www.backyardnature.net/econitro.htm
(810 words)
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| | Stimulation of Nitrogen Fixation in Refractory Organic Sediments by Caulerpa taxifolia (Chlorophyta) |
| | taxifolia appears to enhance N-2 fixation by releasing photosynthetic product into the rhizosphere, mimicking the behavior of saltwater vascular plants. | | | Stimulation of Nitrogen Fixation in Refractory Organic Sediments by Caulerpa taxifolia (Chlorophyta), Observatoire Océanologique Européen. | | | Stimulation of Nitrogen Fixation in Refractory Organic Sediments by Caulerpa taxifolia (Chlorophyta) |
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http://sgnis.org/publicat/chismoul.htm
(238 words)
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| | Michael Swanwick's Periodic Table of Science Fiction |
| | Bacterial agents, called nitrogen fixers, are found in the nodules of leguminous plants, such as alfalfa, peas, and soybeans. | | | Nitrogen fixation is the process of extracting free nitrogen from the air by combining it with other elements, either by chemical means or by bacterial action. | | | There are many commercial means of nitrogen fixation. |
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http://www.scifi.com/scifiction/elements/nitrogen.html
(180 words)
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| | Olympic Hands on the Land |
| | Without the help of certain blue-green algae and bacteria, nitrogen is useless to most plants and animals. | | | Fixed Nitrogen, nitrates and nitrites (brown circles) - After the air's nitrogen is converted to nitrates, it can then be used to create proteins by plants and animals. | | | Nitrogen Fixation - The process by which the air's nitrogen is converted to nitrates. |
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http://www.nps.gov/olym/hand/process/ncycle.htm
(270 words)
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| | nitrogen fixation - Hutchinson encyclopedia article about nitrogen fixation |
| | Several chemical processes duplicate nitrogen fixation to produce fertilizers&; see nitrogen cycle. | | | Process by which nitrogen in the atmosphere is converted into nitrogenous compounds by the action of micro-organisms, such as cyanobacteria (see blue-green algae) and bacteria, in conjunction with certain legumes (see root nodule). | | | This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. |
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http://encyclopedia.farlex.com/nitrogen+fixation
(117 words)
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| | Natural History: Out of Thin Air - nitrogen fixers |
| | No animal, plant, fungus, or protist has mastered the chemical art of converting the abundant gaseous form of nitrogen into a biologically useful one. | | | At that time, the energy and heat generated by these random events were the only forces in nature capable of breaking the powerful chemical bond that holds the two atoms of [N.sub.2] together. | | | A very special group of microbes tap into the atmosphere's huge storehouse of nitrogen and make it available to the rest of us. |
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http://www.findarticles.com/p/articles/mi_m1134/is_7_110/ai_78334672
(457 words)
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| | 2000 GRC on NITROGEN FIXATION |
| | "The Development of Chemical, Biological, and Genetic Approaches to the Study of Nitrogen Fixation Over the Past 30 Years" | | | There will also be a session on the synthesis and biosynthesis of iron-sulfur clusters in other enzyme systems. | | | Signal transduction to the Azotobacter vinelandii NIFL-NIFA regulatory system in response to fixed nitrogen is influenced directly by interaction with 2-oxoglutarate and the PII regulatory protein" |
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http://www.grc.uri.edu/programs/2000/nitro.htm
(395 words)
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