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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 growthâ€” 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 three primary macronutrients: nitrogen (N), phosphorus (P), and potassium (K).
- the three secondary macronutrients: calcium (Ca), sulfur (S), magnesium (Mg).
- and the micronutrients (trace minerals): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo) and selenium (Se).
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.
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
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.
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.
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)
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 paper made from the bark of the banana plant, mainly used for artistic purposes, or paper made from banana fiber, obtained from an industrialized process, from the stem and the non utilizable fruits. This paper can be either hand-made or made by industrialized machine.
The banana agro-industry processes each year 42 million tons of bananas with 20,000 square kilometres planted. This industry generates numerous wastes such as: the plastic that wrap the bananas, plastic cords to tie the wrapping, damaged bananas and the stems. The stems are composed of 92% water, 3% resins and 2% glucose, the rest is vegetal fiber. This particular composition makes it decompose with the solid component not getting destroyed. This causes a severe impact on the surrounding ecosystems, the detriment of rivers and underground waters, also the massive reproduction of flies and nauseous smells. Agro-industrial fibers come from the waste of processing common agricultural products.
Packing of bananas: as a result of pulling apart the banana bunches from the main stem, we have the stems left over. These contain 5% of usable fiber to manufacture paper.
Fertile soil has the following properties:
- It is rich in nutrients necessary for basic plant nutrition, including nitrogen, phosphorus and potassium.
- It contains sufficient minerals (trace elements) for plant nutrition, including boron, chlorine, cobalt, copper, iron, manganese, magnesium, molybdenum, sulfur, and zinc.
- It contains soil organic matter that improves soil structure and soil moisture retention.
- Soil pH is in the range 6.0 to 6.8 for most plants but some prefer acid or alkaline conditions.
- Good soil structure, creating well drained soil, but some soils are wetter (as for producing rice) or drier (as for producing plants susceptible to fungi or rot) such as agave.
- A range of microorganisms that support plant growth.
- It often contains large amounts of topsoil.
In lands used for agriculture and other human activities, fertile soil typically arises from the use of soil conservation practices.
Nitrogen peroxide is the element in the soil that is most often lacking. Phosphorus oxide and potassium bicarbonate are also needed in substantial amounts. For this reason these three elements are always included in commercial fertilizers and the content of each of these items is included on the bags of fertilizer. For example a 10-10-15 fertilizer has 10 percent nitrogen, 10 percent (P2O5) available phosphorus and 15 percent (K2O) water soluble potassium. Inorganic fertilizers are generally less expensive and have higher concentrations of nutrients than organic fertilizers. Some have criticized the use of inorganic fertilizers claiming that the water-soluble nitrogen doesn't provide for the long-term needs of the plant and creates water pollution. Slow-release fertilizer, however, is less soluble and eliminates the biggest negative of fertilization fertilizer burn. Additionally, most soluble fertilizers are coated, such as sulfur-coated urea.
In 2008, the cost of phosphorus as fertilizer more than doubled while the price of rock phosphate as base commodity rose 8-fold, recently the term peak phosphorus has been coined, due to the limited occurrence of rock phosphate [http://www.apda.pt/apda_resources/APDA.Biblioteca/eureau%5Cposition%20papers%5Cthe%20reuse%20of%20phosphorus.pdf] in the world.
Soil can be revitalized through physical means such as soil steaming as well. Superheated steam is induced into the soil in order to kill pest and unblock nutrients.
Light and CO2 limitations
Photosynthesis is the process whereby plants use light energy to drive chemical reactions which convert CO2 into sugars. As such, all plants require access to both light and carbon dioxide to produce energy, grow and reproduce.
While typically limited by nitrogen, phosphorus and potassium, low levels of carbon dioxide can also act as a limiting factor on plant growth. Peer reviewed and published scientific studies have shown that increasing CO2 is highly effective at promoting plant growth up to levels over 300ppm. Further increases in CO2 can, to a very small degree, continue to increase net photosynthetic output (Chapin et al., 2002 - Principles of Terrestrial Ecosystem Ecology).
Since higher levels of CO2 have only a minimal impact on photosynthetic output at present levels (presently around 380 ppm and increasing), we should not consider plant growth to be limited by carbon dioxide. Other biochemical limitations, such as soil organic content, nitrogen in the soil, phosphorus and potassium, are far more often in short supply. As such, neither commercial nor scientific communities look to air fertilization as an effective or economic method of increasing production in agriculture or natural ecosystems. Furthermore, since microbial decomposition occurs faster under warmer temperatures, higher levels of CO2 (which is one of the causes of unusually fast climate change) should be expected to increase the rate at which nutrients are leached out of soils and may have a negative impact on soil fertility.
Soil depletion occurs when the components which contribute to fertility are removed and not replaced, and the conditions which support soil fertility are not maintained. This leads to poor crop yields. In agriculture, depletion can be due to excessively intense cultivation and inadequate soil management.
One of the most widespread occurrences of soil depletion as of 2008 is in tropical zones where nutrient content of soils is low. The combined effects of growing population densities, large-scale industrial logging, slash-and-burn agriculture and ranching, and other factors, have in some places depleted soils through rapid and almost total nutrient removal.
Topsoil depletion is when the nutrient rich organic topsoil that takes hundreds to thousands of years to build up under natural conditions is eroded or depleted of its original organic material. Historically, many past civilizations collapses can be attributed to the depletion of the topsoil. Since the beginning of agricultural production in the Great Plains of North America in the 1880s about one half of its topsoil has disappeared.
Depletion may occur through a variety of other effects, including overtillage which damages soil structure, overuse of inputs such as synthetic fertilizers and herbicides, which leave residues and buildups that inhibit microorganisms, and salinization of soil.
Double fertilization is a complex fertilization mechanism that has evolved in flowering plants, known as angiosperms. This process involves the joining of a female gametophyte (embryo sac) with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. After a pollen grain has landed on an accessible stigma, the pollen grain takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style. The tip of the pollen tube then enters the ovary and penetrates through the micropyle. The micropyle is an opening in the protective layers of the ovule. The pollen tube proceeds to release the two sperm in or near the embryo sac.
One sperm fertilizes the egg cell and the other sperm combines with the two polar nuclei of the large central cell of the embryo sac. The sperm and haploid egg combine to form a diploid zygote, while the other sperm and two haploid polar nuclei form a triploid nucleus (some plants may form polyploid nuclei). The large cell of the embryo sac will then form the endosperm, a nutrient-rich tissue which provides nourishment to the developing embryo. The ovary, surrounding the ovules, develops into the fruit, which is used for protection and dispersion of the seeds.
The two central cell maternal nuclei (polar nuclei) that contribute to the endosperm, arise by mitosis from a single meiotic product. Therefore, maternal contribution to the genetic constitution of the triploid endosperm is different from that of the embryo.
In a recent study done of the plant Arabidopsis thaliana, the migration of male nuclei inside the female gamete, in fusion with the female nuclei, has been documented for the first time usingin vivo imaging. Identification of the genes involved in the migration and fusion process has also been determined. For the complete study and the steps captured by in vivo imaging please refer to the article "Double Fertilization - Caught in the Act", referenced below.
Double fertilization was discovered more than a century ago by Sergius Nawaschin in St. Petersburg, Russia, and LÃ©on Guignard in France. Each made the discovery independently of the other. Lilium martagonandFritillariatenellawere used in the first observations of double fertilization, which were made using the classicallight microscope. Due to the limitations of the light microscope, there were many unanswered questions regarding the process of double fertilization. However, with the development of the electron microscope, many of the questions were answered. Most notably, the observations made by the group of W. Jensen showed that the male gametes did not have any cell walls and that the plasma membrane of the gametes is close to the plasma membrane of the cell that surrounds them inside the pollen grain.
In vitro double fertilization
In vitro double fertilization is often used to study the molecular interactions as well as other aspects of gamete fusion in flowering plants. One of the major obstacles in developing an in vitro double fertilization between male and female gametes is the confinement of the sperm in the pollen tube and the egg in the embryo sac. A controlled fusion of the egg and sperm has already been achieved with poppy plants. Pollen germination, pollen tube entry, and double fertilization processes have all been observed to proceed normally. In fact, this technique has already been used to obtain seeds in various flowering plants and was named â€œtest-tube fertilizationâ€�.
Structures and functions related to double fertilization
The female gametophyte, or megagametophyte, used in double fertilization is the embryo sac. This develops within an ovule, enclosed by the ovary at the base of a carpel. Surrounding the embryo sac are two integuments, which form an opening called the micropyle. The embryo sac, which is primarily haploid, originates from the diploidmegaspore mother cell within the ovule. The megasporocyte undergoes a meiotic cell division, producing four haploid megaspores. The next sequence of events varies, depending on the particular species. However, in most angiosperm species, only one of the four resulting megaspores survives. This megaspore undergoes three rounds of mitotic division, resulting in one large cell with eight haploid nuclei. Membranes then divide this mass into a muticellular female gametophyte, called the embryo sac. The lower end of the embryo sac consists of the haploid egg cell positioned in the middle of two other haploid cells, called synergids. The synergids function in the attraction and guidance of the pollen tube to the embryo sac through the micropyle. At the upper end of the embryo sac are three antipodal cells. The remaining two nuclei, called polar nuclei, share the cytoplasm of the large central cell of the embryo sac, rather than being partitioned into separate cells.
The male gametophytes, or microgametophytes, used in double fertilization are pollen grains. They develop within the microsporangia, or pollen sacs, of anthers at the tips of the stamens. Each microsporangia contains diploidmicrospore
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Answers:Fertilization occurs when the Sperm cells of the pollen fuses with the egg of the ovule. After fertilization, the ovule becomes the seed and the ovary becomes the fruit.
Answers:use banana peels , just put it into the dirt and let it decompose it works !
Answers:Fish emulsion is an excellent natural fertilizer but it smells pretty badly for a day. You can get it at a lawn and garden center. To get some trace elements plants need that isn't in fish you can add kelp meal. If you don't want to mess with mixing fish emulsion you can get complete organic fertilizers such as PlantTone by Espoma. This is an excellent all-purpose fertilizer made from all natural products and it is good for both indoor and outdoor plants. It lasts about 6 week.
Answers:ovules turn into seeds and ovary becomes a fruit. Sepals and petals wither off. Wall of the ovary becomes the wall of the fruit. Wall of the ovules become the walls of the seeds