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Contour Trenching
Contour trenching is an agricultural technique that can be easily applied in arid sub-Sahara areas to allow for water, and soil conservation, and to increase agricultural production. Between two trenches crops can benefit during the growing season (when there is less rain) from the subsoil water reserve gathered during the rainy season. Advantages Immediate advantages are the following: *The rain water does not immediately run off the hill, *Water does not evaporate uselessly *The water balance is enhanced *Crops do not suffer later on from water shortage, *Fertile soil particles are not lost by water and wind erosion. *When the sun shines on the water, light and heat are reflected onto plants on the northern shore of the trench, this effect and the increased humidity create micro climates in the area. These micro climates can support plants from different hardiness zones. Techniques Trenches can be artificially dug along the contour lines, across the slope so that water flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arid
A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most arid climates straddle the Equator; these regions include parts of Africa, Asia, South America, North America, and Australia. Change over time The distribution of aridity at any time is largely the result of the general circulation of the atmosphere. The latter does change significantly over time through climate change. For example, temperature increase by 1.5–2.1 percent across the Nile Basin over the next 30–40 years could change the region from semi-arid to arid, significantly reducing the land usable for agriculture. In addition, changes in land use can increase demands on soil water and thereby increase aridity. See also * Arid Forest Research Institute * Aridity index * Desert climate * Desiccation tolerance * Drou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contour Line
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function f(x,y) parallel to the (x,y)-plane. More generally, a contour line for a function of two variables is a curve connecting points where the function has the same particular value. In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes. The contour interval of a contour map is the difference in elevation between successive contour lines. The gradient of the function is always perpendicular to the contour lines. When the lines are close together the magnitude of the grad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Conservation
Water conservation includes all the policies, strategies and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet the current and future human demand (thus avoiding water scarcity). Population, household size and growth and affluence all affect how much water is used. Factors such as climate change have increased pressures on natural water resources especially in manufacturing and agricultural irrigation. Many countries have already implemented policies aimed at water conservation, with much success. The key activities to conserve water are as follows: any beneficial reduction in water loss, use and waste of resources, avoiding any damage to water quality; and improving water management practices that reduce the use or enhance the beneficial use of water. Technology solutions exist for households, commercial and agricultural applications. Water conservation programs involved in social solutions are typically initiated at t ... [...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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrology (agriculture)
Agricultural hydrology is the study of water balance components intervening in agricultural water management, especially in irrigation and drainage. Water balance components The water balance components can be grouped into components corresponding to zones in a vertical cross-section in the soil forming reservoirs with inflow, outflow and storage of water: # the surface reservoir (''S'') # the root zone or unsaturated (vadose zone) (''R'') with mainly vertical flows # the aquifer (''Q'') with mainly horizontal flows # a transition zone (''T'') in which vertical and horizontal flows are converted The general water balance reads: * inflow = outflow + change of storage and it is applicable to each of the reservoirs or a combination thereof. In the following balances it is assumed that the water table is inside the transition zone. Surface water balance The incoming water balance components into the surface reservoir (''S'') are: #Rai – Vertically incoming water to the surface e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Recharge
Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and is often expressed as a flux to the water table surface. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone. Recharge occurs both naturally (through the water cycle) and through anthropogenic processes (i.e., "artificial groundwater recharge"), where rainwater and or reclaimed water is routed to the subsurface. Processes Water is recharged naturally by rain and snow melt and to a smaller extent by surface water (rivers and lakes). Recharge may be impeded somewhat by human activities including paving, development, or logging. These activities can result in loss of topsoil resulting in reduced water infiltration, enhanced surface run ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrace (agriculture)
In agriculture, a terrace is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, which resemble steps, for the purposes of more effective farming. This type of landscaping is therefore called terracing. Graduated terrace steps are commonly used to farm on hilly or mountainous terrain. Terraced fields decrease both erosion and surface runoff, and may be used to support growing crops that require irrigation, such as rice. The Rice Terraces of the Philippine Cordilleras have been designated as a UNESCO World Heritage Site because of the significance of this technique. Uses Terraced paddy fields are used widely in rice, wheat and barley farming in east, south, southwest, and southeast Asia, as well as the Mediterranean Basin, Africa, and South America. Drier-climate terrace farming is common throughout the Mediterranean Basin, where they are used for vineyards, olive trees, cork oak, and other crops. Ancient hist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyline Design
Keyline design is a landscaping technique of maximizing the beneficial use of the water resources of a tract of land. The "keyline" is a specific topographic feature related to the natural flow of water on the tract. Keyline design is a system of principles and techniques of developing rural and urban landscapes to optimize use of their water resources. Australian farmer and engineer P. A. Yeomans invented and developed Keyline design in his books ''The Keyline Plan'', ''The Challenge of Landscape'', ''Water For Every Farm'', and ''The City Forest''. Application P. A. Yeomans published the first book on Keyline design in 1954. Yeomans described a system of amplified contour ripping to control rainfall runoff and enable fast flood irrigation of undulating land without the need for terracing it. Keyline designs include irrigation dams equipped with through-the-wall lockpipe systems, gravity feed irrigation, stock water, and yard water. Graded earthen channels may be interlink ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swale (landform)
A swale is a shady spot, or a sunken or marshy place. In US usage in particular, it is a shallow channel with gently sloping sides. Such a swale may be either natural or human-made. Artificial swales are often infiltration basins, designed to manage water runoff, filter pollutants, and increase rainwater infiltration. Bioswales are swales that involve the inclusion of plants or vegetation in their construction, specifically. On land This swale concept has also been popularized as a rainwater harvesting and soil conservation strategy by Bill Mollison, David Holmgren, and other advocates of permaculture. In this context it is usually a water-harvesting ditch on contour, also called a ''contour bund''. Swales as used in permaculture are designed to slow and capture runoff by spreading it horizontally across the landscape (along an elevation contour line), facilitating runoff infiltration into the soil. This archetypal form of swale is a dug-out, sloped, often grassed or reede ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabric
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the only manufacturing method, and many other methods were later developed to form textile structures based on their intended use. Knitting and non-woven are other popular types of fabric manufacturing. In the contemporary world, textiles satisfy the material needs for versatile applications, from simple daily clothing to bulletproof jackets, spacesuits, and doctor's gowns. Textiles are divided into two groups: Domestic purposes onsumer textilesand technical textiles. In consumer textiles, aesthetics and comfort are the most important factors, but in technical textiles, functional properties are the priority. Geotextiles, industrial textiles, medical textiles, and many other areas are examples of technical textiles, whereas cloth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrubs
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple stems and shorter height, less than tall. Small shrubs, less than 2 m (6.6 ft) tall are sometimes termed as subshrubs. Many botanical groups have species that are shrubs, and others that are trees and herbaceous plants instead. Some definitions state that a shrub is less than and a tree is over 6 m. Others use as the cut-off point for classification. Many species of tree may not reach this mature height because of hostile less than ideal growing conditions, and resemble a shrub-sized plant. However, such species have the potential to grow taller under the ideal growing conditions for that plant. In terms of longevity, most shrubs fit in a class between perennials and trees; some may only last about five ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and pasture. The latter are commonly referred to collectively as grass. With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as feed for meat-producing animals. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%, wheat supplies 20%, maize (corn) 5.5%, and other grains 6%. Some members of the Poaceae are used as building materials (bamboo, thatch, and straw); others can provide a source of bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
