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Title: Evaluation of Crop Water Stress Based On Soil Moisture, Evapotranspiration, and Canopy Temperature

Author
item YU, QIANG - CHINESE ACADEMY OF SCIENC
item XU, S. - CHINESE ACADEMY OF SCIENC
item Ma, Liwang
item Ahuja, Lajpat

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/8/2006
Publication Date: 11/13/2006
Citation: Yu, Q., Xu, S., Ma, L., Ahuja, L.R. 2006. Evaluation of Crop Water Stress Based On Soil Moisture, Evapotranspiration, and Canopy Temperature. ASA-CSSA-SSSA Annual Meeting Abstracts. Indianapolis, IN. November 13, 2006.

Interpretive Summary: The prediction of plant water status is a key issue of water management. Water stress on crop may alter energy balance at the soil-atmosphere interface, and the change in canopy temperature, which in turn affects transpiration and photosynthesis. An experiment was conducted at the Yucheng Integrated Agricultural Experimental Station from 2003 to 2005 to study crop (wheat-corn) water stress index (CWSI) and its relationship with atmospheric evaporation demand and soil water constraint. Eddy covariance method was applied to measure CO2 and water fluxes, as well as canopy temperature and soil water content. Diurnal change in CWSI was derived using half-hourly flux data. Results showed a linear relationship between CWSI and water use efficiency (WUE). Soil water was better correlated to average daily WUE than hourly WUE. We also found that differences between air and canopy temperature were closely related to soil water content.

Technical Abstract: The prediction of plant water status is a key issue of water management. Water stress on crop may alter energy balance at the soil-atmosphere interface, and the change in canopy temperature, which in turn affects transpiration and photosynthesis. An experiment was conducted at the Yucheng Integrated Agricultural Experimental Station from 2003 to 2005 to study crop (wheat-corn) water stress index (CWSI) and its relationship with atmospheric evaporation demand and soil water constraint. Eddy covariance method was applied to measure CO2 and water fluxes, as well as canopy temperature and soil water content. Diurnal change in CWSI was derived using half-hourly flux data. Results showed a linear relationship between CWSI and water use efficiency (WUE). Soil water was better correlated to average daily WUE than hourly WUE. We also found that differences between air and canopy temperature were closely related to soil water content.