ARS | Publication request: WATER AND HEAT REGIME IN A FIELD SOIL

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 1996
Publication Date: N/A

Technical Abstract: A field experiment was conducted at Riverside, California, to study diurnal heat and water regime near the soil surface. Hourly soil moisture content, soil temperature, and soil matric potential measurements were made at 50 sites and 3 depths along two orthogonal transects under different irrigation events (for 40 days). (150) TDRs, (150) thermocouples, and (35) tensiometers were used in conjunction with (30) multiplexers and a number of data loggers for monitoring purposes. Following the field experiment, soil cores were collected at the same locations for measuring the temperature-dependent hydraulic properties. This study is aimed at understanding the spatio-temporal variability of non-isothermal water flow near the soil surface as well as to develop and test model(s) for coupled heat-water flow in variably- saturated soil system. Preliminary analyses of data showed diurnal spatio-temporal hysteresis phenomenon (between the spatial mean and the spatial variance) both in soil temperature and soil moisture content. However, differences were found in the magnitude and trend of the diurnal spatio-temporal hysteresis between soil temperature and corresponding soil moisture content during dry and wet days, at our field site.