Tuesday, November 6, 2007
184-3

Spatial Variability of near-Surface and Profile Water Content: Sensors Impact the Result.

Steven Evett1, Naem Th. Mazahrih2, Judy A. Tolk1, Terry A. Howell1, and Nedal Katbeh Bader3. (1) USDA-ARS, USDA-ARS, PO Box 10, Bushland, TX 79012, (2) National Centre for Agricultural Research and Technology Transfer, Amman - Irbid Highway Street, P.O.Box 639, Baq'a 19381, Jordan, (3) Irrigation Specialist, Ramallah, Palestine

Spatial variability of soil water content has been shown to vary depending on time since wetting, plant vigor and variability, and sample size. The profile water content to a give profile depth is different from the variability of near-surface water content. Four electromagnetic sensors, the neutron moisture meter and gravimetric sampling were used to assess spatial and temporal variability of near-surface (top 10 cm) and profile (0 to 100 cm) water content over periods of natural rainfall, deficit irrigation and full irrigation. Sensor type and measurement method had a large effect on statistics of spatial variability.