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From Wikipedia

Fertilizer

Fertilizers (or fertilisers) are substances that supply plant nutrients or amend soil fertility. They are the most effective (30 -80 per cent increase in yields) means of increasing crop production and of improving the quality of food and fodder. Fertilizers are used in order to supplement nutrient supply in the soil, especially to correct yield-limiting factors.

Fertilizers are applied to promote plant growth; the main nutrients present in fertilizer are nitrogen, phosphorus, and potassium (the 'macronutrients') and other nutrients ('micronutrients') are added in smaller amounts. Fertilizers are usually directly applied to soil, and can also be sprayed on leaves as a foliar feeding.

Organic fertilizers and some mined inorganic fertilizers have been used for many centuries, whereas chemically synthesized inorganic fertilizers were only widely developed during the industrial revolution. Increased understanding and use of fertilizers were important parts of the pre-industrial British Agricultural Revolution and the industrial Green Revolution of the 20th century.

Inorganic fertilizer use has also significantly supported global population growth— it has been estimated that almost half the people on the Earth are currently fed as a result of artificial nitrogen fertilizer use.

Fertilizers typically provide, in varying proportions:

The macronutrients are consumed in larger quantities and are present in plant tissue in quantities from 0.2% to 4.0% (on a dry matter weight basis). Micronutrients are consumed in smaller quantities and are present in plant tissue in quantities measured in parts per million (ppm), ranging from 5 to 200 ppm, or less than 0.02% dry weight.

The nitrogen-rich fertilizer ammonium nitrate is also used as an oxidizing agent in improvised explosive devices, sometimes called fertilizer bombs, leading to sale regulations.

Labeling

Macronutrient fertilizers

Macronutrient fertilizers are labeled with an NPKanalysis (also "N-P-K-S" in Australia).

Fertilizer is described by a three number designator; for example, 20-20-10. These numbers are percentages of three elements: nitrogen, phosphorus, and potassium, respectively. Therefore, 20-20-10 fertilizer contains 20% nitrogen, 20% phosphorus, and 10% potassium by weight.

Example of labeling

The fertilizer potash(potassium carbonate) is composed of 1:1 potassium to carbonate by volume (47:53 by wt., owing to differences inmolecular weight between potassium and carbonate).

Traditional analysis of 100g of potassium chloride (KCl) would yield 60g of potassium oxide (K2O). The percentage yield of K2O from the original 100g of fertilizer is the number shown on the label. A potash fertilizer would thus be labeled 0-0-60, and not 0-0-52.

History

The modern understanding of plant nutrition dates to the 19th century and the work of Justus von Liebig, among others. Management of soil fertility, however, has been the pre-occupation of farmers for thousands of years.

Forms

Fertilizers come in various forms. The most typical form is granular fertilizer (powder form). The next most common form is liquid fertilizer; some advantages of liquid fertilizer are its immediate effect and wide coverage. There are also slow-release fertilizers (various forms including fertilizer spikes, tabs, etc.) which reduce the problem of "burning" the plants due to excess nitrogen.

Finally, organic fertilizer is on the rise as people are resorting to environmental friendly (or 'green') products. Although organic fertilizer usually contain less nutrients, some people still prefer organic due to natural ingredients.

Inorganic fertilizer (synthetic fertilizer)

Fertilizers are broadly divided into organic fertilizers (composed of enriched organic matter—plant or animal), orinorganic fertilizers (composed ofsynthetic chemicals and/or minerals).

Inorganic fertilizer is often synthesized using the Haber-Bosch process, which produces ammonia as the end product. This ammonia is used as a feedstock for other nitrogen fertilizers, such as compost, manure), or naturally-occurring mineral deposits (e.g. saltpeter).

Naturally-occurring organicfertilizers includemanure, slurry, worm castings, peat, seaweed, humic acid, and guano. Sewage sludge use in organic agricultural operations in the U.S. has been extremely limited and rare due to USDA prohibition of the practice (due to toxic metal accumulation, among other factors).

Processed organic fertilizers include compost, bloodmeal, bone meal, humic acid, amino acids, and seaweed extracts. Other examples are natural enzyme digested proteins, fish meal, and feather meal. Decomposing crop residue (green manure) from prior years is another source of fertility.

Discussion of the term 'organic'

There used to be a distinction between the term "organic" and the term "pesticide free". Organic simply dealt with the use of fertilizer types. Once the term "organic" became regulated, many other factors were added. "Pesticide-free" is not at all related to fertilization (plant nutrition), but has become a legal inclusion.

Likewise, in scientific terms, a fish emulsion can be a good organic fertilizer :), but in some jurisdictions fish emulsion must be certified "dolphin safe" to be considered "organic".

Natural sourcing

Animal-sourced Urea and Urea-Formaldehyde (from urine), are suitable for application organic agriculture, while pure synthetic forms are not deemed, however, pure (synthetically-produced) urea is not. The common thread that can be seen through these examples is that organic agriculture attempts to define itself through minimal processing (e.g. via chemical energy such as petroleum—see Haber process), as well as being naturally-occurring or via natural biological processes such as composting.

Cover crops are also grown to enrich soil as a green manure through nitrogen fixation from the atmosphere; as well as phosphorus (through nutrient mobilization) content of soils.

Powdered limestone, mined rock phosphate and Chilean saltpeter, are inorganic chemicals in the technical (organic chemistry) sense of the word, but are considered suitable for organic agriculture in limited amounts..

Advantages

Although the density of nutrients in organic material is comparatively modest, they have many advantages. The majority of nitrogen supplying organic fertilizers contain insoluble nitrogen and act as a slow-release fertilizer. By their nature, organic fertilizers increase physical and biological nutrient storage mechanisms in soils, mitigating risks of over-fertilization. Organic fertilizer nutrient content, solubility, and nutrient release rates are typically much lower than mineral (inorganic) fertilizers. A University of North Carolina study found that potential mineralizable nitrogen (PMN) in the soil was 182–285% higher in organic mulched systems, than in the synthetics control.

Organic fertilizers also re-emphasize the role of humus and other organic components of soil, which are believed to play several important roles:

  • Mobilizing existing soil nutrients, so that good growth is achieved with lower nutrient densities while wasting less
  • Releasing nutrients at a slower, more consistent rate, helping to avoid a boom-and-bust pattern
  • Helping to retain soil moisture, reducing the stress due to temporary moisture stress
  • Improving the soil structure
  • Helping to prevent topsoil erosion (responsible for desertfication and the Dust bowl

Organic fertilizers also have the advantage of avoiding certain problems associated with the regular heavy use of artificial fertilizers:

  • The necessity of reapplying artificial fertilizers regularly (and perhaps in increasing quantities) to maintain fertility
  • Extensive runoff of soluble nitrogen and phosphorus, leading to eutrophication of bodies of water (which causes fish kills)
  • Costs are lower for if fertilizer is locally available

According to the PPI institute website, it is widely thought that organic fertilizer is better than inorganic fertilizer. However, balanced responsible use of either or both can be just as good for the soil.

Disadvantages

Organic fertilizers have the following disadvantages:

  • As a dilute source of nutrients when compared to inorganic fertilizers, transporting large amount of fertilizer incurs higher costs, especially with slurry and manure.
  • The composition of organic fertilizers tends to be more complex and variable than a standardized inorganic product.
  • Improperly-processed organic fertilizers may contain pathogens from plant or animal matter that are harmful to humans or plants. However, proper composting should remove them.
  • More labor is needed to compost organic fertilizer, increasing labor costs. Some of this cost is offset by reduced cash purchase.

Conventional farming application

In non-organic farming a compromise between the use of artificial and organic fertilizers is common, often using inorganic fertilizers supplemented with the application of organics that are readily available such as the


From Yahoo Answers

Question:websites would help!

Answers:Organic fertilizers improve the soil which in turn feeds the plant instead of just feeding the plant. The plant is able to take up what it needs in the right amount and at the right time. Organic pesticides if used properly are the least harmful to the environment and other organisms. Part of organic gardening is to identify what the problem is and then do something about it instead of just applying a pesticide that harms a wide variety of pests which may not even include what is causing the problem. This website has more information and links which you may find helpful. http://www.squidoo.com/gardenorganically

Question:I want to know the advantages of organic pesticides and organic fertilizers. Not the disadvantages just the advantages. And please state a source Sorry. Its Organic Fertilizers and Natural Psticides.

Answers:Advantage of organic pesiticides is you don't have to worry about giving yourself cancer when you apply it or when you or others eat the food. Another is its far cheaper and most of the time you can make them yourself with just a blender. Also, most organic pesticides don't poison drinking water and kill wildlife and pets. With the fertilizers the biggest advantage is that they work better in the long haul, although chemicals work better in the short haul.They don't poison your drinking water supply permanently like chemical fertilizers can do. They don't burn and kill worms which are very desirable to have in your soil the way chemical fertilizers do. I hope this helps you.

Question:I really need help!!! Plz just tell me the advantages!!!!

Answers:Fertilizers replace the chemicals that your plants deplete from the soil. The chemicals originally got there over a period of millions of years of volcanic activity miles from there. the dust is in the air and rain brings it down. Surely you don't think you are going to get something for nothing. You don't need pesticides. You can pick the bugs off the plants by hand.

Question:give points and examples of pesticides. Also show where info was taken from (give links).

Answers:I don't know about indiscriminate, but there have been several insecticides that that had long range problems. Cloridane for termite control in Florida is now prohibited because it got into groundwater supplies. It's long life was good for termite control but bad for the water. DDT was another. An excellent insecticide that was also a little too long lasting. It got into the water, built up in fish and was then transfered to eagles when they ate the fish with thin egg shells being the result. Thin shelled eggs broke before they could hatch. DDT is still used in many parts of the world for mosquito control. Without it, malaria would kill or affect millions of people. If anyone is going to use pesticides indiscriminately or unwisely, it's probably the average urban homeowner. They figure if a little is good, then a lot is better. If they spend a couple of dollars extra by over applying the pesticide or fertilizer to their yard or garden, so what. Pesticides are very expensive and the farmer can't afford to overapply or apply when not needed.

From Youtube

Pesticides In Foods Affect Male Fertility :Naturalpath.com - Check out this video and other great "green living" resources on www.naturalpath.com!

Agricultural Pollution - Pesticides, Herbicides and Fertilizers :A video for ENGL 314.