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All plants need certain mineral elements for proper growth, development, and maintenance. The basic structure of all organisms is built of carbon (C), oxygen (O) and hydrogen (H). Plants obtain these elements from water (H2O) in the soil and carbon dioxide (CO2) in the air, so no input is required beyond being sure the plant has an adequate water supply to meet its needs. Turning the H2O and CO2 into organic building blocks, however, is a complex process that requires the assistance of at least 13 other elements.

Three elements, nitrogen (N), phosphorus (P), and potassium (K), are required in relatively large quantities and are referred to as primary or macronutrients. N is an important component of all protein, so is integral to the plant structure. P is a minor component of protein, but is integral to the molecules that control energy flow within the plant and is a component of genetic material. The role of K seems to be in maintaining the correct salt concentration in the plant sap. N, P, and K, in varying ratios, are the primary constituents of all chemical fertilizers. Depending on the fertilizer origin, their amounts present may be expressed as N, P2O5, and K2O.



  1. Ressource principale
    20/01/2009 All plants need certain mineral elements for proper growth, development, and maintenance. The basic structure of all organisms is built of carbon (C), oxygen (O) and hydrogen (H). Plants obtain these elements from water (H2O) in the soil and carbon dioxide (CO2) in the air, so no input is...
  2. 20/07/2005 Joel Matthewsreceived some feedbackabout his comments on low fertility soil and traditional varieties in EDN 86. In response, he sent the following additional comment.
  3. 20/01/2002 The conventional view of the relationship between soil nutrients and crop productivity in the tropics is leading to both damaging agricultural policies and inefficient and damaging farm-level practices. There is no need to use the huge quantities of chemical fertilizers that are so often...
  4. 20/04/2013 An important principle of conservationagriculture is that of targeted, precision applications of organic or inorganic fertilizer near crop plants, as opposed to evenly dispersing inputs over an entire field. In a row-crop setting, this can be done by banding fertilizer next to the crop plants. In...
  5. 01/07/2022 Ce système de compostage par les poulets est adapté du système enseigné par Geoff Lawton, consultant en permaculture, concepteur, auteur et enseignant. Ce système a été enseigné à Jordan par Geoff Lawton dans le cadre de l'un de ses cours de conception en permaculture, puis il l'a adapté au...
  6. 20/01/2005 Maradi Integrated Development Project has forced me to question the wisdom of assuming that increases of organic content and fertility are always best.
  7. This section looks at the way in which soil quality can be maintained and improved through a number of techniques including the use of fertilizer, manure and compost.
  8. 08/02/2017 Cover crops play a key role in sustainable agriculture by providing sustainable sources of nutrients as well as protective soil cover to minimize erosion and reduce moisture stresses. Examples of successful cover cropping systems in East Africa will be illustrated as well as constraints and...
  9. 20/04/2020 The editable source documents (.docx and .pub)of these materials are available in many other languages fromthe CFGB database. The source documents are updated periodically so check here for the most current formats. We encourage you to adapt the source for your purposes. Learning Outcomes –...
  10. Abstract, Makerere University Dissertations, 2019 Low crop yields due to low erratic rainfall, high evapo-transpiration, and deteriorating soil fertility in semi-arid areas of the country, have led to a quest for sustainable production practices with greater resource use efficiency in order...
  11. 12/02/2019 Session: Ken’s research focuses on smallholder farming systems in sub-Saharan Africa, and in particular problems of soil fertility with emphasis on nitrogen fixation by legumes and the temporal and spatial dynamics of resources within crop/livestock farming systems. Biographical information: Ken...
  12. Small holder farmers and practitioners from Tanzania share agroecology best practices to improve soil fertility. English Subtitles
  13. 20/12/2012
  14. 20/11/2019 Swahili Only
  15. 20/01/2011
  16. 06/02/2018 Speaker Bio: Dr. Tom Thompson is Associate Dean and Director of International Programs in the College of Agriculture and Life Sciences and Professor of Agronomy at Virginia Tech. He earned B.S. , M.S. , and Ph.D. degrees in agronomy and soil science. He was an academic department head at two...
  17. Session:Ken’s research focuses on smallholder farming systems in sub-Saharan Africa, and in particular problems of soil fertilitywith emphasis on nitrogen fixation by legumes and the temporal and spatial dynamics of resources within crop/livestock farming systems. Biographical information:Ken...
  18. 04/10/2017 It is often a problem in tropical soils farmed by smallholders that the soil is nutrient-depleted and acidic, costing the farmer more money and yielding less valuable crops. In an attempt to overcome this, Dr. Tom will discuss different ways of evaluating important soil properties and thus...
  19. En observant les feuilles de maïs, on peut diagnostiquer quatre carences en éléments nutritifs - phosphore, potassium, azote et magnésium. Ce document comprend des photos d'une feuille de maïs en bonne santé et de feuilles de maïs démontrant chacune de ces carences en éléments nutritifs. Il...
  20. 16/02/2015 Every February-March, rice fields are burned throughout Thailand. These very low temperature burns produce huge amounts of smoke that causes serious public health problems, as well as greenhouse gases, smog precursors, dioxin and furans. This practice also destroys valuable organic matter...
  21. 03/10/2017 Soils of smallholder farmers are often depleted of organic matter and available soil nutrients, and may also be acidic and/or saline. We will review the causes and extent of these soil-related challenges in the developing world. A variety of possible management responses to these challenges will...
  22. 06/02/2018 Speaker Bio: Dr. Tom Thompson is Associate Dean and Director of International Programs in the College of Agriculture and Life Sciences and Professor of Agronomy at Virginia Tech. He earned B.S. , M.S. , and Ph.D. degrees in agronomy and soil science. He was an academic department head at two...
  23. AccessAgriculture Training Video Le but principal est de réduire les coûts et d'améliorer le profit. La santé et l'humidité des sols sont améliorées. La Zambie est en avance en Afrique au Sud du Sahara et ce programme montre comment la technique est mise en oeuvre. Langues disponibles Anglais...
  24. AccessAgriculture Training Video Pour des cultures saines, il faut un sol sain, car un sol sain contient de nombreux bons microbes et vers de terre. Pour préparer un biofertilisant pour un demi-hectare, il faut 10 kilogrammes de bouse de vache fraîche, de l’urine de vache, de farine de pois...
  25. AccessAgriculture Training Video Le jus de vermicompost est un liquide recueilli après le passage de l'eau dans le compost fait à partir des vers de terre. Il est riche en hormones de croissance végétale, en micronutriments et en nutriments essentiels comme l’azote, le phosphore et le potassium....
  26. AccessAgriculture Training Video Introduction aux pratiques de gestion durables des sols qui ont fait l'objet de suivi et dont les données sont enregistrées en Afrique. Elles peuvent aider à controller la dégradation des sols et à ameliorer la production des petits producteurs, malgré les défis...
  27. AccessAgriculture Training Video La gestion intégrée de la fertilité des sols est basée sur la maximisation de l'utilisation des fertilisants organiques (biologiques) et la minimisation des pertes de nutriments. Langues disponibles Anglais Bemba Chichewa / Nyanja Chitonga / Tonga Espagnol...
  28. Access Agriculture Training Video Mix legumes and grasses to improve the soil fertility, and the nutritional value of the feed. It also improves the yields of the potatoes that you plant next. If you are not able to irrigate, plant the fodder at the beginning of the rains. The mix should include...
  29. 19/01/1985 Cet Agrodok est une édition révisée qui englobe deux Agrodoks publiés précédemment (Agrodok 2: ‘Fertilité du sol’, et Agrodok 28: ‘Engrais vert’). Nous les avons réunis car l’engrais vert offre aux petits exploitants agricoles une possibilité supplémentaire d’améliorer la fertilité du sol. En...
  30. Frontiers in Soil Scienceprovides a forum for research excellence in all aspects of soil science. We welcome article submissions in the traditional fields of soil chemistry, physics, and biology as well as those involved in pedology and soil classification. In addition, we invite submissions that...
  31. Thomas, Richard & El Dessougi, Hanadi & Tubeileh, Ashraf. (2006). Soil System Management Under Arid and Semi-Arid Conditions. 10.1201/9781420017113.ch4. Soil fertility in systems under arid and semi-arid conditions, hereafter referred to as dry areas or drylands, is constrained by...
  32. 18/03/2016 For courses in Soil Fertility, Nutrient Management, and Plant Nutrition in Agriculture. Covering all aspects of nutrient management for profitable crop production, the text pays particular attention to minimizing the environmental impact of soil and fertilizer management. Soil Fertility and...
  33. 08/02/2017 Neil Rowe Miller serves with Mennonite Central Committee as a technical advisor to conservation agriculture projects funded by the Canadian Food Grains Bank in eastern Africa. His career spans 33 years working with small-scale farmers in the developing world as well as consultingfor large-scale...
  34. 01/10/2019 Soil infertility is a key constraint to crop production for small farmers. Soils throughout Sub-Saharan Africa are degraded and deficient in nutrients and organic matter. As a result, there is a growing demand for soil testing services from farmers and NGO staff who want guidance on which inputs...

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