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A field enclosure apparatus for measuring crop photosynthesis
Author(s) -
LEACH J. E.
Publication year - 1979
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1979.tb02965.x
Subject(s) - enclosure , transpiration , photosynthesis , carbon dioxide , environmental science , water vapor , atmospheric sciences , nitrous oxide , environmental chemistry , hydrology (agriculture) , biology , botany , ecology , chemistry , meteorology , physics , telecommunications , geotechnical engineering , computer science , engineering
SUMMARY The field enclosure is a transparent box covering a soil area of 1.5 m 2 . It is a semi‐closed system in which concentrations of water vapour and carbon dioxide are maintained constant: the required rate of input of carbon dioxide being a measure of the photosynthesis rate, and the rate of condensation of water, on cooling coils, a measure of transpiration. The air within the enclosure is circulated rapidly by fans to decrease concentration gradients, and under steady radiation inputs the air temperature is controlled to ±0.5 °C. Both photosynthesis and transpiration rates are corrected for air exchange with the surroundings, as measured through the injection of the inert gas, nitrous oxide.