Evapotranspiration In The Soil Plant Atmosphere System

Evapotranspiration and its components (evaporation and transpiration) as a process is one of the basic terms of Earth's water balance; its importance is accented by the fact that transpiration is the vital element of the biomass production process. The second important property of evapotranspiration is its extreme consumption of solar energy, thus controlling the temperature of the atmosphere and creating favourable conditions for life. Evapotranspiration as an energy consuming process is also the connection between the energy and mass cycles of the Earth. Evapotranspiration is a process performing in the Soil–Plant –Atmosphere System (SPAS); therefore this book is presenting and quantifying it as a catenary process, describing transport of water in the soil, including root extraction patterns and methods of its evaluation. Transport of water through the plant and from the canopy to the atmosphere is also described and quantified. A variety of evapotranspiration (and its components evaporation and transpiration) calculation methods are described, starting from empirical methods up to the most sophisticated ones based on the solution of the transport equations of water and energy in the SPAS. The most important (and widely used) calculation method - modified Penman–Monteith method is described in details, ready to be used with data in the book only. Water balance method of evapotranspiration estimation as well as sap flow method description can be found in the book as well. The book can be used by hydrologists, biologists, meteorologists and other specialists as well as by ecology students. Key themes: soil hydrology – evapotranspiration – hydropedology– plant physiology – water movement in soils – evaporation – transpiration Dr. Viliam Novák is a water resources scientist at the Institute of Hydrology of the Slovak Academy of Sciences in Bratislava (Slovakia).

This textbook presents the concepts and processes involved in the soil-plant-atmosphere system as well as its applications in the water cycle in agriculture. Although reaching the frontier of our knowledge in several subjects, each chapter starts at the graduation level and proceeds to the post-doctoral level. Its more complicated subjects, as math and physics, are well explained, even to readers not well acquainted with these tools. Therefore, it helps students read, understand, and developing their thoughts on these subjects. Instructors also find it an easy book with the needed depth to be adopted in courses related to Soil Physics, Agricultural Management, Environmental Protection, Irrigation and Agrometeorology. It serves also as “lexicon” to engineers and lawyers involved in agricultural, environmental cases.

The following advances in technology for measurement of water potential are described: (1) A thermocouple for direct attachment to plant leaves; (2) A microchamber for studying plant responses to environment is described. Light intensity and duration, ambient temperature, relative humidity, and CO2 concentration are controlled. Transpiration, CO2 assimilation, and plant and soil water potential are measured. Data for the ratio of transpiration to CO2 assimilation for cotton are given. Moderate salinity increased this ratio. Description of a contact closure distributor to make a data acquisition system serve as a control device as well as a recorder is given. Also described is a tape editor for handling output data from the system. Preliminary results from experiments to determine how plants integrate time varying salinity indicate that transpiration per unit leaf area is decreased by salinity. (Author).

This Encyclopedia of Agrophysics will provide up-to-date information on the physical properties and processes affecting the quality of the environment and plant production. It will be a "first-up" volume which will nicely complement the recently published Encyclopedia of Soil Science, (November 2007) which was published in the same series. In a single authoritative volume a collection of about 250 informative articles and ca 400 glossary terms covering all aspects of agrophysics will be presented. The authors will be renowned specialists in various aspects in agrophysics from a wide variety of countries. Agrophysics is important both for research and practical use not only in agriculture, but also in areas like environmental science, land reclamation, food processing etc. Agrophysics is a relatively new interdisciplinary field closely related to Agrochemistry, Agrobiology, Agroclimatology and Agroecology. Nowadays it has been fully accepted as an agricultural and environmental discipline. As such this Encyclopedia volume will be an indispensable working tool for scientists and practitioners from different disciplines, like agriculture, soil science, geosciences, environmental science, geography, and engineering.

Fluxes of trace gases, water and energy - the 'breathing of the biosphere' - are controlled by a large number of interacting physical, chemical, biological and ecological processes. In this interdisciplinary book, the authors provide the tools to understand and quantitatively analyse fluxes of energy, organic compounds such as terpenes, and trace gases including carbon dioxide, water vapour and methane. It first introduces the fundamental principles affecting the supply and demand for trace gas exchange at the leaf and soil scales: thermodynamics, diffusion, turbulence and physiology. It then builds on these principles to model the exchange of water, carbon dioxide, terpenes and stable isotopes at the ecosystem scale. Detailed mathematical derivations of commonly used relations in biosphere-atmosphere interactions are provided for reference in appendices. An accessible introduction for graduate students and a key resource for researchers in related fields, such as atmospheric science, hydrology, meteorology, climate science, biogeochemistry and ecosystem ecology.

The title provides an overview of the current knowledge about the diversity of the living world and the various problems associated with its conservation and sustainable use. Covering both the fundamentals of the subject, along with the latest research, Biodiversity presents key conservation issues within a framework of global case studies. Starting with a summary of the concept of biodiversity, the text then explores such subjects as species richness, ecological systems, the consequences of human activities, diversity and human health, genetic resources, biotechnology and conservation. Comprehensive introduction to key issues surrounding the study of biodiversity. Extensive bibliography and references to numerous relevant websites. Introduces current research in the field within a framework of useful case studies.

A laboratory technique is described for independent measurement of the total soil water potential and its components, based on the principles of the soil psychrometer and the porous plate apparatus. Only a negligible quantity of soil water is displaced. Such data are used to study interactions of the water potential New plant growth chambers are being built at Riverside to study the transport of water from the soil to the atmosphere through plants. The sunlit plastic-enclosed chambers have provisions for control of temperature, humidity, CO2 concentration, light intensity, and air velocity. Each chamber will be 20 feet high, with nearly 10 feet below the soil surface level to accommodate deep soil columns. A pepper plant was grown through three irrigation cycles in a soil column 130 cm deep; soil water potential was measured with tensiometers and a thermocouple psychrometer; plant water potential was inferred from a calibrated beta gauge; transpiration was measured by weighing the soil-plant system. Water movement in the transpiration stream was in the direction of the water potential gradient. Regardless of the distribution of water in the soil, transpiration was unaffected by declining soil water until it reached a level corresponding to about -8 bars soil water potential. Beyond this, transpiration decreased linearly with soil water content to a soil water potential of -37 bars, at which time the plant water potential was below -50 bars and transpiration was essentially zero. After irrigation, the plant regained full turgor. (Author).