Water balance

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  • LIFE IN EARTH’S ATMOSPHERE presents a formidable challenge to land plants. On the one hand, the atmosphere is the source of carbon dioxide, which is needed for photosynthesis. Plants therefore need ready access to the atmosphere. On the other hand, the atmosphere is relatively dry and can dehydrate the plant. To meet the contradictory demands of maximizing carbon dioxide uptake while limiting water loss, plants have evolved adaptations to control water loss from leaves, and to replace the water lost to the atmosphere.

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  • Water is finite on earth. There is a fixed amount of water which neither decreases or increases. Fresh water is a renewable resource because of the water cycle. From a human perspective the source of freshwater is rainfall. Most of this rainfall is used directly for vegetative growth, such as natural vegetation, pasture, rain-fed maize etc. This process, known as transpiration, is highly productive and produces in Southern Africa the bulk of food crops.

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  • WATER PLAYS A CRUCIAL ROLE in the life of the plant. For every gram of organic matter made by the plant, approximately 500 g of water is absorbed by the roots, transported through the plant body and lost to the atmosphere. Even slight imbalances in this flow of water can cause water deficits and severe malfunctioning of many cellular processes. Thus, every plant must delicately balance its uptake and loss of water. This balancing is a serious challenge for land plants. To carry on photosynthesis, they need to draw carbon dioxide from the atmosphere, but doing so exposes them to...

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  • Vietnam-Netherlands Mekong Delta Masterplan project: Me Kong delta water resources assessment studies has many contents: description of the mekong delta of Viet Nam, hydrology and surface water resources, water quality, hydrogelogy and groundwater recources, water demand and water balance, issues to be solved.

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  • Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Variation of stomatal resistance with leaf age in Quercus petraea: effect on the soil-water balance of an oak forest...

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  • Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Water balance of a Southern Moravian floodplain forest under natural and modified soil water regimes and its ecological consequences...

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  • Evapotranspiration - An Overview contains recent advances in the physics of evaporation and transpiration from a typical experimental site to large scale areas. It incorporates many years of authors experience with the latest research on the methods and the models used worldwide, engaging advanced technology and modern instrumentation. The reader benefits from the in-depth analysis and the diverse sites and settings, where the models, applications and methods are tested.

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  • 6 Study on the Intra-Annual Distribution Characteristics of the Water Budget in the Hilly Region of Red Soil in Northeast Jiangxi Province, China Junfeng Dai, Jiazhou Chen, Yuanlai Cui, and Yuanqiu He 6.1 INTRODUCTION In northeast Jiangxi Province, water balance is important for water resource utilization and agricultural regionalization. In this region, the red soil is affected by the subtropical monsoon climate in which rainfall is abundant, but unevenly distributed (Chen and Zhang 2002). The high intensity of rainfall leads to water loss during the rainy season.

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  • IN BOTH NATURAL AND AGRICULTURAL CONDITIONS, plants are frequently exposed to environmental stresses. Some environmental factors, such as air temperature, can become stressful in just a few minutes; others, such as soil water content, may take days to weeks, and factors such as soil mineral deficiencies can take months to become stressful. It has been estimated that because of stress resulting from climatic and soil conditions (abiotic factors) that are suboptimal, the yield of field-grown crops in the United States is only 22% of the genetic potential yield (Boyer 1982).

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  • SURVIVAL ON LAND POSES SOME SERIOUS CHALLENGES to terrestrial plants, foremost of which is the need to acquire and retain water. In response to these environmental pressures, plants evolved roots and leaves. Roots anchor the plant and absorb water and nutrients; leaves absorb light and exchange gases. As plants increased in size, the roots and leaves became increasingly separated from each other in space. Thus, systems evolved for long-distance transport that allowed the shoot and the root to efficiently exchange products of absorption and assimilation.

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  • The force that through the green fuse drives the flower Drives my green age; that blasts the roots of trees Is my destroyer. And I am dumb to tell the crooked rose My youth is bent by the same wintry fever. The force that drives the water through the rocks Drives my red blood; that dries the mouthing streams Turns mine to wax. And I am dumb to mouth unto my veins How at the mountain spring the same mouth sucks. Dylan Thomas, Collected Poems (1952) In these opening stanzas from Dylan Thomas’s famous poem, the poet proclaims the essential unity...

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  • IN NATURAL HABITATS, plants are surrounded by an enormous number of potential enemies. Nearly all ecosystems contain a wide variety of bacteria, viruses, fungi, nematodes, mites, insects, mammals, and other herbivorous animals. By their nature, plants cannot avoid these herbivores and pathogens simply by moving away; they must protect themselves in other ways. The cuticle (a waxy outer layer) and the periderm (secondary protective tissue), besides retarding water loss, provide barriers to bacterial and fungal entry.

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  • Rapid socio–economic development leads to a great increase in water demand of many sectors and conflicts between water users. Moreover, studies have warned about serious degree of influence of climate change (CC) on Vietnam, particularly on the water resources. Therefore, assess CC impacts on water balances are very necessary task. The Ministry of Natural Resources and Environment has completed the appropriate climate change scenarios in Vietnam [1].

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  • Traditional Chinese Medicine: TCM considers the patient as a microcosm of the universe, subject to the influences of the environment and internal harmony. Patients are subject to the interplay of external factors such as wind, heat, dryness, dampness and cold which act on the elemental qualities of the human body such as wood, fire, earth, metal and water.

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  • The Mekong River Delta in Vietnam can be considered as a large tropical wetland, in which two typical eco-forest wetlands can be distinguished: the inland Melaleuca forest wetlands and the coastal mangrove forest wetlands. Their main functions are the provision of forest commodities, the regulation of the water balance and biodiversity conservation. However as elsewhere under human pressure their existence is under the threat of forest fires and deforestation. Their protection requires the implementation of a multi-level national or sub-national planning policy.

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  • Balances Scientific and Economic Points of View to Thoroughly Address Management Issues Responding to the need for clarification and benchmarks, Environmental Life Cycle Costing provides the fundamental basis on which to establish a definitive methodology. Clearly defining environmental LCC, this book balances scientific and economic points of view and thoroughly addresses the management perspective.

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  • This textbook covers Plant Ecology from the molecular to the global level.

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  • Although Feng has been practiced in the Eastern hemisphere for thousands of years, it is relatively new to western civilization. Feng Shui may seem mysterious and foreign to our western culture, but it is actually a very sensible collection of ideas and actions. Once you understand its principles, you will be able to produce harmony, comfort and balance in almost any situation or environment.

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  • MINERAL NUTRIENTS ARE ELEMENTS acquired primarily in the form of inorganic ions from the soil. Although mineral nutrients continually cycle through all organisms, they enter the biosphere predominantly through the root systems of plants, so in a sense plants act as the “miners” of Earth’s crust (Epstein 1999). The large surface area of roots and their ability to absorb inorganic ions at low concentrations from the soil solution make mineral absorption by plants a very effective process.

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  • HIGHER PLANTS ARE AUTOTROPHIC ORGANISMS that can synthesize their organic molecular components out of inorganic nutrients obtained from their surroundings. For many mineral nutrients, this process involves absorption from the soil by the roots (see Chapter 5) and incorporation into the organic compounds that are essential for growth and development. This incorporation of mineral nutrients into organic substances such as pigments, enzyme cofactors, lipids, nucleic acids, and amino acids is termed nutrient assimilation....

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