Since soil is made up of such diverse materials like broken down rock particles and organic material, it can be classified into various types, though based on the size of the particles it contains.
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Different Types of Soil - 0 views
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Soil Types
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Sandy soil Silty soil Clay soil Loamy Soil Peaty Soil Chalky Soil
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Sandy Soil- This type has the biggest particles and the size of the particles does determine the degree of aeration and drainage that the soil allows.
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formed by the disintegration and weathering of rocks such as limestone, granite, quartz and shale
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In a way sandy soil is good for plants since it lets the water go off so that it does not remain near the roots and lead them to decay.
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the perfect soil
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composed of minerals like Quartz and fine organic particles.
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This type of soil can hold more moisture and at times becomes compact.
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Clay Soil-Clay is a kind of material that occurs naturally and consists of very fine grained material with very less air spaces
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it is difficult to work with since the drainage in this soil is low, most of the time there is a chance of water logging and harm to the roots of the plant
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Loamy Soil- This soil consists of sand, silt and clay to some extent
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Silty Soil-Silty soil is considered to be one of the most fertile of soils.
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out of all the different kinds of soil loamy soil is the ideal for cultivation.
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Peaty Soil- This kind of soil is basically formed by the accumulation of dead and decayed organic matter
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Though the soil is rich in organic matter, nutrients present are fewer in this soil type than any other type
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if the soil is fertilized well and the drainage of the soil is looked after, it can be the ideal for growing plants.
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Chalky Soil-Unlike Peaty soil, Chalky soil is very alkaline in nature and consists of a large number of stones.
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A description of six different, common types of soil and what varies between them.
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AccessScience | Research Update | Phototropin - 0 views
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Typically, stems show positive phototropism (movement toward the light), whereas roots exhibit negative phototropic movement (away from the source of light).
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Arabidopsis contains two phototropins referred to as phot1 and phot2. Mutants of Arabidopsis lacking both phototropins lose their phototropic responsiveness
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Phototropic response
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phototropins control the movement of chloroplasts
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these responses serve to enhance the photosynthetic
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Phototropins, like photoreceptor pigments associated with mammalian vision, comprise many amino acids (900–1000) that form the main structure of the protein (the apoprotein) to which an accessory chemical cofactor is bound that can absorb light and impart color (the chromophore)
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a small fraction of the receptor pool is rapidly internalized (within minutes) upon blue light irradiation
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Phototropins are typically associated with the plasma membrane
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However, the biological significance
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As light passes through the stem, it becomes progressively diffracted, thereby generating a gradient of phototropin activation across the organ, with the highest level of activity occurring on the irradiated side
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In some plant species, including the fern Adiantum capillus-veneris, phototropism and chloroplast movement are induced by red light as well as blue.
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novel
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The presence of such a hybrid photoreceptor is proposed to enhance light sensitivity and aid the prevalence of species such as ferns in low light conditions
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Hypoxia in the Northern Gulf of Mexico - 2 views
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Hypoxia, or oxygen depletion, is an environmental phenomenon where the concentration of dissolved oxygen in the water column decreases to a level that can no longer support living aquatic organisms.
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Hypoxic and anoxic (no oxygen) waters have existed throughout geologic time, but their occurrence in shallow coastal and estuarine areas appears to be increasing as a result of human activities (Diaz and Rosenberg, 1995). The largest hypoxic zone currently affecting the United States, and the second largest hypoxic zone worldwide, occurs in the northern Gulf of Mexico adjacent to the Mississippi River on the Louisiana/Texas continental shelf.
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What causes hypoxia? Major events leading to the formation of hypoxia in the Gulf of Mexico include: Freshwater discharge and nutrient loading of the Mississippi River Nutrient-enhanced primary production, or eutrophication Decomposition of biomass by bacteria on the ocean floor Depletion of oxygen due to stratification
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Mississippi River nutrient concentrations and loading to the adjacent continental shelf have greatly changed in the last half of the 20th century. During this time there has been a marked increase in the concentration of nitrogen and phosphorous in the Lower Mississippi River. This increase has been attributed to the increased use of nitrogen and phosphorous fertilizers,
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Eutrophication
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eutrophication initiates a massive growth of phytoplankton on the water’s surface.
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This stratification leaves the bottom layer isolated from the surface layer and cut off from a normal resupply of oxygen from the atmosphere.
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Hypoxia was first documented in the northern Gulf of Mexico off the Louisiana coast in 1972.
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Essential Plant Nutrients - 1 views
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Essential plant nutrients: their relative amounts in plants, functions and classification
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This table may be helpful in determining a topic for an experiment. You would only want to choose one nutrient with which to run an experiment.
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Five types of deficiency or toxicity symptoms are observed:
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Here are the visible signs if the soil does not have enough of or too much of a nutrient.
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Plants can be damaged is there is too much of one nutrient (toxicity) or not enough of a nutrient (deficiency).
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Nutrients (in the soid) are needed either in large amounts (macronutrients), medium amounts (micronutrients), or in trace amounts
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Table 2. Generalized Symptoms of Plant Nutrient Deficiency or Excess
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Plant hormone and growth regulators - 0 views
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(Table 5)
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Hormones are produced naturally by plants, while plant growth regulators are applied to plants by humans
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This is interesting because it shows you that if you want to manipulate hormones in an experiment you can use plant growth regulators to mimic the action of hormones.
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There are five groups of plant-growth-regulating compounds: auxin, gibberellin (GA), cytokinin, ethylene, and abscisic acid (ABA).
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Ethylene is unique in that it is found only in the gaseous form. It
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induces ripening, causes leaves to droop (epinasty) and drop (abscission), and promotes senescence.
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The effects of ethylene (promotion of both aging/death and ripening) may explain why just one bad apple in a basket may spoil the whole bunch.
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Plant hormones and growth regulators are chemicals that affect flowering; aging; root growth; killing of leaves; prevention or promotion of stem elongation; color enhancement of fruit; prevention of leafing and/or leaf fall; etc.
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AccessScience | Encyclopedia Article | Soil fertility - 1 views
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Sixteen chemical elements are required for the growth of all plants: carbon, oxygen, and hydrogen (these three are obtained from carbon dioxide and water), plus nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, zinc, copper, boron, molybdenum, and chlorine. Some plant species also require one or more of the elements cobalt, sodium, vanadium, and silicon.
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13 essential mineral nutrien
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J. R. Brown (ed.), Recommended Chemical Soil Test Procedures for the North Central Region, Missouri Agricultural Experiment Station, Columbia, 1998
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Note the Bibliography. I've highlighted an article, available as a pdf file, with information on interesting experimental procedures for how to handle and test soil. Might be helpful for your experimental design.
