|
Liman Irrigation System
A Liman (from Greek λιμήν) in Israel is the name for an artificial earthen construction used to collect floodwater by damming a desert wadi. The runoff water is slowed by the dam, thus flooding a small area and allowing the water to infiltrate into the soil. This way, a small groves of trees can be sustained in the desert. The JNF-KKL has been funding the construction of limans in the Negev Desert. Introduction Limans were built in order to fight desertification without depleting groundwater resources, which are becoming increasingly rare in arid ecosystems.Prinz, D. 2002. The role of water harvesting in alleviating water scarcity in arid areas. In Proceedings, International Conference on Water Resources Management in Arid Regions. 23–27 March 2002, 107–122. Kuwait: Kuwait Institute for Scientific Research Available at: Remaining soil humidity can be found in dry river beds (wadis) after rains occur, but these wadis are prone to flash floods. The result is massive s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewish National Fund Trees In The Negev
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The people of the Kingdom of Israel and the ethnic and religious group known as the Jewish people that descended from them have been subjected to a number of forced migrations in their history" and Hebrews of historical Israel and Judah. Jewish ethnicity, nationhood, and religion are strongly interrelated, "Historically, the religious and ethnic dimensions of Jewish identity have been closely interwoven. In fact, so closely bound are they, that the traditional Jewish lexicon hardly distinguishes between the two concepts. Jewish religious practice, by definition, was observed exclusively by the Jewish people, and notions of Jewish peoplehood, nation, and community were suffused with faith in the Jewish God, the practice of Jewish (religious) la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acacia
''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus name is New Latin, borrowed from the Greek (), a term used by Dioscorides for a preparation extracted from the leaves and fruit pods of '' Vachellia nilotica'', the original type of the genus. In his ''Pinax'' (1623), Gaspard Bauhin mentioned the Greek from Dioscorides as the origin of the Latin name. In the early 2000s it had become evident that the genus as it stood was not monophyletic and that several divergent lineages needed to be placed in separate genera. It turned out that one lineage comprising over 900 species mainly native to Australia, New Guinea, and Indonesia was not closely related to the much smaller group of African lineage that contained ''A. nilotica''—the type species. This meant that the Australasian lineag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamarind
Tamarind (''Tamarindus indica'') is a leguminous tree bearing edible fruit that is probably indigenous to tropical Africa. The genus ''Tamarindus'' is monotypic, meaning that it contains only this species. It belongs to the family Fabaceae. The tamarind tree produces brown, pod-like fruits that contain a sweet, tangy pulp, which is used in cuisines around the world. The pulp is also used in traditional medicine and as a metal polish. The tree's wood can be used for woodworking and tamarind seed oil can be extracted from the seeds. Tamarind's tender young leaves are used in Indian and Filipino cuisine. Because tamarind has multiple uses, it is cultivated around the world in tropical and subtropical zones. Description The tamarind is a long-lived, medium-growth tree, which attains a maximum crown height of . The crown has an irregular, vase-shaped outline of dense foliage. The tree grows well in full sun. It prefers clay, loam, sandy, and acidic soil types, with a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucalyptus Sargentii
''Eucalyptus sargentii'', commonly known as Salt River gum, is a species of mallet, mallee or small tree that is endemic to Western Australia. It has rough bark on part or all of the trunk, smooth bark above, linear to narrow lance-shaped leaves, flower buds in groups of seven, whitish to creamy yellow flowers and conical fruit. Description ''Eucalyptus sargentii'' is a tree or a mallee that typically grows to a height of but does not usually form a lignotuber (a mallet). It has smooth greenish bark that is brownish when new, usually with rough, greyish flaky bark on part or all of the trunk. Adult leaves are arranged alternately, the same shade of green on both sides, linear to narrow lance-shaped or curved, long and wide tapering to a petiole long. The flower buds are arranged in leaf axils in groups of seven on an unbranched peduncle long, the individual buds on pedicels long. Mature buds are an elongated oval shape, long and wide with a horn-shaped operculum that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucalyptus Occidentalis
''Eucalyptus occidentalis'', commonly known as the flat topped yate or the swamp yate, is a tree that is native to Western Australia. The Noongar names for the tree are Mo or Yundill. Description The tree or mallee typically grows to height of with the diameter of approximately . The form of the tree is to usually have a short trunk which branches fairly low to form several stout primary branches. The canopy is predominantly terminal, giving the tree an umbrella-like appearance, and is moderately dense. It forms rough, fibrous and flaky dark grey or black bark mostly on the trunk that becomes conspicuously smooth white, sometimes powdery, on the upper trunk and branches. Adult leaves are glossy-green in colour with a lanceloate shape. Seedling or coppice growth is often present with conspicuous dull blue-green broadly ovate leaves. It flowers early for most Eucalypts, in its first year of growth. It produces cream-white flowers between September and May. Seeds are produced in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infiltration (hydrology)
Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the maximum rate of infiltration. It is most often measured in meters per day but can also be measured in other units of distance over time if necessary. The infiltration capacity decreases as the soil moisture content of soils surface layers increases. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. Infiltrometers, permeameters and rainfall simulators are all devices that can be used to measure infiltration rates. Infiltration is caused by multiple factors including; gravity, capillary forces, adsorption and osmosis. Many soil characteristics can also play a role in determining the rate at which infiltration occurs. Factors that affect infiltration Precipitation Precipitation can impact infiltration in many ways. The a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Compaction
In geotechnical engineering, soil compaction is the process in which stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or other liquid) being displaced from between the soil grains, then consolidation, not compaction, has occurred. Normally, compaction is the result of heavy machinery compressing the soil, but it can also occur due to the passage of, for example, animal feet. In soil science and agronomy, soil compaction is usually a combination of both engineering compaction and consolidation, so may occur due to a lack of water in the soil, the applied stress being internal suction due to water evaporation as well as due to passage of animal feet. Affected soils become less able to absorb rainfall, thus increasing runoff and erosion. Plants have difficulty in compacted soil because the mineral grains are pressed together, leaving little space for air and water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grazing (behaviour)
Grazing is a method of feeding in which a herbivore feeds on low-growing plants such as grasses or other multicellular organisms, such as algae. Many species of animals can be said to be grazers, from large animals such as hippopotamuses to small aquatic snails. Grazing behaviour is a type of feeding strategy within the ecology of a species. Specific grazing strategies include graminivory (eating grasses); coprophagy (producing part-digested pellets which are reingested); pseudoruminant (having a multi-chambered stomach but not chewing the cud); and grazing on plants other than grass, such as on marine algae. Grazing's ecological effects can include redistributing nutrients, keeping grasslands open or favouring a particular species over another. Ecology Many small selective herbivores follow larger grazers which skim off the highest, tough growth of grasses, exposing tender shoots. For terrestrial animals, grazing is normally distinguished from browsing in that grazing is eat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levee
A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastlines. The purpose of a levee is to keep the course of rivers from changing and to protect against flooding of the area adjoining the river or coast. Levees can be naturally occurring ridge structures that form next to the bank of a river, or be an artificially constructed fill or wall that regulates water levels. Ancient civilizations in the Indus Valley, ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters. Etymology Speakers of American English (notably in the Midwest and Deep South) use the word ''levee'', from the French word (from the feminine past participle of the French verb , 'to raise'). It originated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spillway
A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that water does not damage parts of the structure not designed to convey water. Spillways can include floodgates and fuse plugs to regulate water flow and reservoir level. Such features enable a spillway to regulate downstream flow—by releasing water in a controlled manner before the reservoir is full, operators can prevent an unacceptably large release later. Other uses of the term "spillway" include bypasses of dams and outlets of channels used during high water, and outlet channels carved through natural dams such as moraines. Water normally flows over a spillway only during flood periods, when the reservoir has reached its capacity and water continues entering faster than it can be released. In contrast, an intake tower is a stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Runoff
Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is saturated by water to its full capacity, and the rain arrives more quickly than the soil can absorb it. Surface runoff often occurs because impervious areas (such as roofs and pavement) do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or man-made processes. Surface runoff is a major component of the water cycle. It is the primary agent of soil erosion by water. The land area producing runoff that drains to a common point is called a drainage basin. Runoff that occurs on the ground surface before reaching a channel can be a nonpoint source of pollution, as it can carry man-made contaminants or natural forms of pollution (such as rotting leaves). Man-made contaminants in runoff i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
