Premium
A Portable Chamber for Measuring Canopy Gas Exchange of Crops Subject to Different Root Zone Conditions 1
Author(s) -
Meyer W. S.,
Reicosky D. C.,
Barrs H. D.,
Shell G. S. G.
Publication year - 1987
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1987.00021962007900010037x
Subject(s) - lysimeter , gas analyzer , canopy , environmental science , ionization chamber , evapotranspiration , dns root zone , soil water , agronomy , soil science , chemistry , botany , ionization , environmental chemistry , ion , ecology , organic chemistry , biology
The measurement of above ground plant function is an integral part of monitoring crop response to root zone conditions. The objective of this work was to adapt a field gas exchange chamber technique to a lysimeter facility so that apparent photosynthesis (APS) and evapotranspiration (ET) of cotton ( Gossypium hirsutum L.) could be studied. A cylindrical chamber covered with clear Teflon film was manipulated with a gantry to enclose plants growing in each of 32 different soil cores within a lysimeter facility. Air was circulated within the chamber and sub‐sampled to measure change in CO 2 and H 2 O vapor concentrations with an infra‐red gas analyser (IRGA) during a 45‐s‐measurement period. Measurement timing and data processing were computer controlled. Sensitivity of measurement was ± 0.02 mg CO 2 m −2 s −1 for APS and ± 4.5 mg H 2 O m −2 s −1 for ET which was about 2 to 3% of values measured in a well‐watered, fully developed cotton canopy. Values of ET from IRGA measurements were similar ( P >0.05, r 2 =0.89) to those calculated from psychrometer measurements. The system permits accurate, rapid, and repetitive measurements over soil cores in which concurrent measurements of root zone conditions can be made.