TITLE:
Continuously Monitored Canopy Temperature as a Proxy for Plant Water Status
AUTHORS:
James R. Mahan, Andrew W. Young, Paxton Payton
KEYWORDS:
Canopy Temperature, Cotton, Drip Irrigation, Evapotranspiration, Gossypium hirsutum, Yield
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.6 No.14,
September
11,
2015
ABSTRACT: Water deficits are major limiters of crop yield worldwide. The detection of water deficits can be
difficult. Measurements of the aerial and soil environment are often used to infer the water status
and detect water deficits. Since crop yield accumulates incrementally and cumulatively over seasonal
time scales, continuous direct monitoring of the water status of the crop may provide
needed insight into plant/environment interactions. Canopy temperature can be measured near
continuously on seasonal scales in the field. Cotton was grown under 11 irrigation regimes in 2009
and 2010 with water deficits from 26% to 86% of crop evapotranspiration. Yield varied accordingly
from ~500 kg·ha-1 to ~2600 kg·ha-1. Canopy temperature was measured on a 15-minute interval
for ~65 days in each year. Yield was described by a linear function of total water (irrigation +
rain) for each year with similar slopes and different intercepts. When canopy temperature was
used as a surrogate for total water, yield was linearly related to daytime leaf-to-air VPD, mean
seasonal canopy temperature, mean seasonal daytime canopy temperature, and cumulative seasonal
daytime canopy temperature. Limiting the analysis to daytime periods improved the ability
to account for yield variation. Mean daytime seasonal canopy temperature and cumulative seasonal
daytime temperature were most effective in accounting for yield variation across the seasons
with a single regression line for both years.