Yellow Dune

picture info	Yellow Dune Yellow dunes are sand dunes that develop after the first set of embryo dunes appear. They have an average depth of about 5m and are composed primarily of sand. They are so named because their lack of humus gives them a yellow color. The percentage of exposed sand on these dunes is generally about 20%. The remaining 80% is covered with vegetation that cannot withstand the conditions on the embryo dunes. The plants on these dunes can withstand the slightly alkaline sand an example of the plants would be marram grass ''spinifex.'' The moisture content Water content or moisture content is the quantity of water contained in a material, such as soil (called ''soil moisture''), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed ... of these dunes is relatively low so the plants still have very strong root structure and are capable of getting every drop of water that comes their way. As this dune develops, a ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Hvid Klit Hvid is a Danish surname literally meaning "white". Notable people with the surname include: Inge Hvid-Møller (1912–1970) was a Danish actress and stage director. Juliane Hvid (born 1998), Danish steeplechase runner * Kigge Hvid, founding CEO of The Index Project, Danish nonprofit organisation that promotes designs aimed at the quality of life See also * Hvide The Hvide clan (English: ''Whites'') was a medieval Danish clan, and afterwards in early modern era a Danish noble surname of presumably one surviving branch of leaders of that clan. Before the 16th century it was not used as a surname. It sign ... ("The Whites"), Danish clan {{White-surname ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
picture info	Sand Dunes A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes, with little or no vegetation, are called '' ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented sand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Latin word for "earth" or "ground". In agriculture, "humus" sometimes also is used to describe mature or natural compost extracted from a woodland or other spontaneous source for use as a soil conditioner. It is also used to describe a topsoil horizon that contains organic matter (''humus type'', ''humus form'', or ''humus profile''). Humus has many nutrients that improve the health of soil, nitrogen being the most important. The ratio of carbon to nitrogen ( C:N) of humus commonly ranges between 8:1 and 15:1 with the median being about 12:1. It also significantly improves (decreases) the bulk density of soil. Humus is amorphous and lacks the cellular structure characteristic of organisms. The solid residue of sewage sludge treatment, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Embryo Dunes An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres (4-cell stage) are arranged as a solid ball that when reaching a certain size, called a morula, (16-cell stage) takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases. Etymology The word ''alkali'' is derived from Arabic ''al qalīy'' (or ''alkali''), meaning (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide (''slaked lime''), a far more strongly basic substance known as ''caustic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Moisture Content Water content or moisture content is the quantity of water contained in a material, such as soil (called ''soil moisture''), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed as a ratio, which can range from 0 (completely dry) to the value of the materials' porosity at saturation. It can be given on a volumetric or mass (gravimetric) basis. Definitions Volumetric water content, θ, is defined mathematically as: :\theta = \frac where V_w is the volume of water and V_\text = V_s + V_w + V_a is equal to the total volume of the wet material, i.e. of the sum of the volume of solid host material (e.g., soil particles, vegetation tissue) V_s, of water V_w, and of air V_a. Gravimetric water content is expressed by mass (weight) as follows: :u = \frac where m_w is the mass of water and m_s is the mass of the solids. For materials that change in volume with water content, such as coal, the gravimetric water content, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Deserts A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or semi-arid. This includes much of the polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night strain the rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting fragments and rubble strewn over the desert floor are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]