Download or read book Calculated and Field measured Soil Heat Flux written by Joseph L. Pikul and published by . This book was released on 1983 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat and water vapor flow in summer-fallowed fields in the Pacific Northwest may significantly affect the position and supply of water for germination of fall sown crops. New tillage tools and drill openers used in reduced tillage systems leave a trashy, residue covered surface in contrast to the traditional bare fallow systems. It is likely that these new management techniques cause changes in heat and water flow that produce unique profiles of soil temperature and water content. There is a need to elucidate heat and mass flow theory under field conditions appropriate to these new tillage systems. However, heat and mass flow theory has been studied almost exclusively in the laboratory using uniformly packed homogeneous soil. Heat flow theory in these experiments has generally consisted of two components: de Vries theoretical estimation of soil thermal conductivity and the Philip formulation of total heat flux consisting of heat flow responses to thermal and moisture gradients. The Philip-de Vries theory was field tested to determine if such theory could be used to project the water conservation aspects of reduced tillage systems. Soil heat flux was calculated using the theory of Philip-de Vries and then compared with soil heat fluxes experimentally determined in a Walla Walla silt loam using a null-alignment of soil temperatures and calorimetric heat flow. Comparisons at 20 depths in the top 60 cm of soil were made during mid-summer on no-till field plots with two soil moisture regimes. All components of heat flow including vapor heat flux terms were used in the theoretical calculations, but isothermal vapor flux accounted for less than 1% of the total vapor flux. Measured net daily heat flux at 0.25 cm was 22.3 and 21.7 cal cm−2 day−1 for the moist and dry treatments, respectively. Theoretical heat flux calculations at this same depth generally gave a tenfold overestimation of measured heat flux during those times of the day when large temperature gradients existed. At 9 cm, approximately the seeding depth of winter wheat, measured net daily heat flux was 14.5 and 20.6 cal cm−2 day−1 for the moist and dry treatments, respectively; respective theoretical fluxes were 15.7 and 32.8 cal cm−2 day−1. Calculated total fluxes in the top 35 cm generally overestimated by 20 and 40 percent, as compared to measured fluxes, for the moist and dry treatments, respectively. Theoretical heat flux vapor components were calculated as the difference between total and conduction heat fluxes. Soil water changes predicted by vapor flux theory agreed with measured seedzone diurnal water content changes on the dry plot. At 35 cm vapor fluxes were negligible. Heat flux by conduction at this same depth over estimated measured flux by 10% on both plots. At all depths theoretical heat flux by conduction was more seriously overestimated than the vapor components of heat flux. The Philip-de Vries heat flux model satisfactorily predicted water changes in dry soil seedbeds by vapor flux theory. Overestimation of the conduction component of the de Vries thermal conductivity produced an overestimation of calculated heat flux on both plots at all depths. Further calibration of the conduction components of the model will be needed to continue assessment of heat and vapor flux in dry seedbeds.

Download or read book Temperature Measurements and the Calculated Heat Flux in the Soil written by Robert Kingsley Maxwell and published by . This book was released on 1964 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methods of Soil Analysis Part 4 written by Jacob H. Dane and published by John Wiley & Sons. This book was released on 2020-05-27 with total page 1744 pages. Available in PDF, EPUB and Kindle. Book excerpt: The best single reference for both the theory and practice of soil physical measurements, Methods, Part 4 adopts a more hierarchical approach to allow readers to easily find their specific topic or measurement of interest. As such it is divided into eight main chapters on soil sampling and statistics, the solid, solution, and gas phases, soil heat, solute transport, multi-fluid flow, and erosion. More than 100 world experts contribute detailed sections.

Download or read book The Measurement of Heat Flow in the Ground and the Theory of Heat Flux Meters written by Peter Schwerdtfeger and published by . This book was released on 1970 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of heat flux meters has been examined by experimental, electrical analogue and numerical means. The results indicate the more general applicability of the flux meter equation first proposed by Philip (1961) for the special case of spheroidal meters, provided certain precautions are taken. The purely geometric parameter appearing in this equation has been related to meter shape and a functional connection has been suggested. It is proposed that pairs of thermal sensors be used to monitor thermal conductivity continuously and the use of nonuniform 'focusing' heat flux meters is recommended in cases where the physical cross section of a thermopile should remain small compared to the resultant thermal cross section. Finally a number of calibration techniques are reported, including the use of a novel radiation enclosure in which meters are temporarily tested as net radiometers, (Author).

Download or read book Field Measurements of Heat Losses from Three Types of Heat Distribution Systems written by Gary E. Phetteplace and published by . This book was released on 1992 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book EPA 600 2 written by and published by . This book was released on 1978 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Land Surface Processes in Atmospheric General Circulation Models written by P. S. Eagleson and published by Cambridge University Press. This book was released on 2011-02-17 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 1982 book consists of papers presented at the World Climate Research Programme study conference on land surface processes held in Greenbelt, Maryland from 5 to 10 January 1981. The papers cover the following: the state of knowledge of the sensitivity of atmospheric general circulation models on hydrology and other land surface processes: assessment of the state of knowledge of numerical modelling of hydrology and other land surface processes at the scale of atmospheric general circulation models; recommendations for research activities; establishment of data requirements for initialization, validation, and parameter evaluation. This book will continue to be of interest to atmospheric scientists, soil physicists, hydrologists and climatologists.

Download or read book Quantification of Deep Percolation from Two Flood irrigated Alfalfa Field Roswell Basin New Mexico written by D. Michael Roark and published by . This book was released on 1998 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ground water Discharge Determined from Measurements of Evapotranspiration Other Available Hydrologic Components and Shallow Water level Changes Oasis Valley Nye County Nevada written by and published by . This book was released on 2002 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Irrigation Return Flow Quality Abstracts written by and published by . This book was released on with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Building Applications of Heat Flux Transducers written by George E. Courville and published by ASTM International. This book was released on 1985 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Reporting Series written by and published by . This book was released on 1978 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimated Ground water Discharge by Evapotranspiration from Death Valley California 1997 2001 written by and published by . This book was released on 2003 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of Evapotranspiration in Phreatophyte Areas Smith Creek Valley and Carson Desert West central Nevada 1983 written by Rita L. Carman and published by . This book was released on 1993 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Irrigation Return Flow Quality Abstracts 1976 written by Gaylord V. Skogerboe and published by . This book was released on 1978 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil and Environmental Analysis written by Keith A. Smith and published by CRC Press. This book was released on 2000-10-12 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reviews a wide range of methods for soil physical analysis. Considers applications, accuracy, measurement time, and cost of equipment. Provides examples of applications."

Download or read book Soil Physics written by T. J. Marshall and published by Cambridge University Press. This book was released on 1996-05-31 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in its third edition, this textbook gives a comprehensive account of soil physics with emphasis on field applications for students and research workers engaged in water resources studies, soil sciences, and plant sciences. The authors have added chapters on soil erosion, conservation, and the role of soil in affecting water quality to this new edition. The book gives an account of how water influences the structure and strength of soil; how plants absorb water from soils; how water from rain and irrigation enters the soil and flows through it to contribute to stream flow and flow in artificial drains; how soluble salts and chemical pollutants are transported; how soils are eroded by water and wind; and how the evaporation rate from the land surface is influenced by soil water supply, the nature of the plant cover and the evaporative power of the atmosphere. This book will be useful to students and research workers in environmental sciences, hydrology, agriculture, soil science, and civil engineering.