Kelley Drechsler Receives ASABE Poster Award

Graduate student Kelley Drechsler was awarded a $250 prize for her poster and presentation at the ASABE's annual international meeting. This year's meeting was held in Detroit, Michigan, July 29th through August 1st. Kelley took 7th place with her poster, “A Comprehensive Stress Indicator for Evaluating Plant Water Status in Almond Trees to Aid in Irrigation Scheduling,”  in the National Resources & Environmental Systems (NRES) community.

Kelley describes here project as "a comprehensive stress indicator that factors in the leaf temperature and environmental conditions that could be used to provide feedback about a farmer’s irrigation management. The Comprehensive Stress Indicator (CSI) is

based on the reformulation of the leaf energy balance equation. Specifically, the CSI is the ratio of the temperature difference between a dry leaf (i.e. a leaf with a broken stem) and a live leaf (on the same tree) and the difference between the vapor pressure inside the stomatal cavity at saturation and the vapor pressure of the air at ambient temperature.

The sensor suite known as the “leaf monitor,” developed by Dr. Shrini Upadhyaya, was used to collect the dry leaf temperature, live leaf temperature, relative humidity and air temperature measurements required to compute the CSI. The leaf monitor provided enough data to compute the CSI every 15 minutes. The CSI was averaged between the 1 PM to 3 PM period to produce the Average Comprehensive Stress Indicator (ACSI) and integrated during the daylight hours to produce the Integrated Comprehensive Stress Indicator (ICSI).

The ACSI and ICSI were satisfactorily correlated with midday stem water potential, which is a direct measurement of the plant’s physiological water status. The advantage of these new stress indicators is that they require measurements only at the tree being monitored, unlike several other existing stress indices in the research literature."