On the assessment of root and soil respiration for soils of different textures: interactions with soil moisture contents and soil CO2 concentrations |
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Authors: | Bouma Tjeerd J Bryla David R |
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Institution: | (1) Department of Horticulture, The Pennsylvania State University, 103 Tyson Building, University Park, PA 16802, USA;(2) Center for Estuarine and Coastal Ecology, Netherlands Institute of Ecology, P.O. Box 140, 4400 AC Yerseke, The Netherlands;(3) Department of Horticulture, The Pennsylvania State University, 103 Tyson Building, University Park, PA 16802, USA;(4) Water Management Research Laboratory, USDA-ARS, Fresno, CA 93727, USA |
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Abstract: | Estimates of root and soil respiration are becoming increasingly important in agricultural and ecological research, but there
is little understanding how soil texture and water content may affect these estimates. We examined the effects of soil texture
on (i) estimated rates of root and soil respiration and (ii) soil CO2 concentrations, during cycles of soil wetting and drying in the citrus rootstock, Volkamer lemon (Citrus volkameriana Tan. and Pasq.). Plants were grown in soil columns filled with three different soil mixtures varying in their sand, silt
and clay content. Root and soil respiration rates, soil water content, plant water uptake and soil CO2 concentrations were measured and dynamic relationships among these variables were developed for each soil texture treatment.
We found that although the different soil textures differed in their plant-soil water relations characteristics, plant growth
was only slightly affected. Root and soil respiration rates were similar under most soil moisture conditions for soils varying
widely in percentages of sand, silt and clay. Only following irrigation did CO2 efflux from the soil surface vary among soils. That is, efflux of CO2 from the soil surface was much more restricted after watering (therefore rendering any respiration measurements inaccurate)
in finer textured soils than in sandy soils because of reduced porosity in the finer textured soils. Accordingly, CO2 reached and maintained the highest concentrations in finer textured soils (> 40 mmol CO2 mol−1). This study revealed that changes in soil moisture can affect interpretations of root and soil measurements based on CO2 efflux, particularly in fine textured soils. The implications of the present findings for field soil CO2 flux measurements are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | citrus Citrus volkameriana root respiration soil CO2 efflux soil CO2 concentration soil water relations Volkamer lemon |
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