ARS | Publication request: Monitoring near surface soil water and associated dynamics of infiltration and evaporation fluxes

Submitted to: European Geosciences Union General Assembly Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 3, 2011
Publication Date: April 3, 2011
Citation: Schwartz, R.C., Evett, S.R., Schlegel, A.J., Baumhardt, R.L. 2011. Monitoring near surface soil water and associated dynamics of infiltration and evaporation fluxes [abstract]. European Geosciences Union General Assembly, April 3-8, 2011, Vienna, Austria.

Technical Abstract: In-situ monitoring of soil water has the advantage of integrating the precipitation, evaporation history, and gradual changes in hydraulic properties on the aggregate response of the system, which is manifested as soil water storage. Near-surface soil water and temperature dynamics were monitored throughout a five-year period on sweep-tilled (ST) and no-till (NT) plots, and through phases of a wheat-sorghum-fallow rotation to examine the temporal dynamics of infiltration and evaporation. Plots were established in a fallow field under stubble-mulch tillage management on a Pullman clay loam. Soil water contents were monitored using time-domain reflectometry (TDR) at 0.05 to 0.3 m and using a neutron moisture gauge to a depth of 2.3 m. Soil temperature, precipitation, and net radiation were also monitored. Cumulative infiltration and evaporation were estimated using a water balance approach, in conjunction with a calibrated drainage model. Soil water contents at 0.05 and 0.1 m were lower in recently tilled ST plots compared with NT, even following repeated precipitation events. Water contents at soil depths >/= 0.15 m were not influenced by tillage. Tillage did not influence cumulative infiltration and evaporation during a three month period during fallow after sorghum. For this three-month observation period, no-tillage did not exhibit significantly improved water storage, despite having greater residue cover. Data from the entire rotation sequence will need to be analyzed to infer tillage effects on the general patterns of infiltration and evaporation.