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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #307167
Title: Continuous measurement of soil evaporation in a drip-irrigated wine vineyard in a desert area

Author
item KOOL, DILIA - Ben Gurion University Of Negev
item AGAM, NURIT - Ben Gurion University Of Negev
item LAZAROVITCH, NAFTALI - Ben Gurion University Of Negev
item HEITMAN, JOSH - North Carolina State University
item Sauer, Thomas
item BEN-GAL, ALON - Agricultural Research Organization Of Israel

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Evaporation from the soil surface (E) can be a significant source of water loss in arid areas. In sparsely vegetated systems, E is expected to be a function of soil, climate, irrigation regime, precipitation patterns, and plant canopy development, and will therefore change dynamically at both daily and seasonal time scales. Current understanding of E in vegetated systems is limited due to the lack of robust techniques to measure E continuously. In this study we assessed two novel techniques, a soil heat balance method and a surface temperature based method, for continuous measurement of E in a drip irrigated vineyard in an arid environment. Specific focus was assessing variations of E both temporally and spatially across the inter-row. Continuous above canopy measurements included evapotranspiration, solar radiation, air temperature and humidity, and wind speed and direction. Short-term intensive measurements below the canopy included E and solar radiation along transects between adjacent vine rows. The intensive measurements were used to validate long-term assessment of E based on soil heat pulse probes and infrared thermometer data combined with existing evaporation models. Below canopy E was highly variable; both diurnally and with distance from the vine-row, as a result of shading and distinct wetted areas typical to drip-irrigation. While the magnitude of actual E was mostly determined by soil water content, diurnal patterns depended strongly on position relative to the vine-row due to variable shading patterns. Results indicate that continuous E data can be obtained from the temperature method, provided the below canopy micro-climate can be adequately modeled. The soil heat balance method can be used as a stand-alone technique and is suitable to assess second stage E. The strengths and weaknesses of each approach will be highlighted.