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Tropospheric Carbon Dioxide or Ozone Enrichments and Moisture Effects on Soil Organic Carbon Quality
Author(s) -
Islam K. R.,
Mulchi C. L.,
Ali A. A.
Publication year - 1999
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1999.00472425002800050029x
Subject(s) - chemistry , carbon dioxide , soil water , tropospheric ozone , environmental chemistry , ozone , soil carbon , charcoal , organic matter , total organic carbon , zoology , environmental science , soil science , organic chemistry , biology
Carbon, as an active component of organic matter, has considerable effects on soil quality and productivity. The objective of this study was to examine the effect of climate change variables on soil organic C ( C T ) quality in an agroecosystem. Wheat ( Triticum aestivum L.) and soybean [ Glycine max (L.) Merr] plants were grown in 3 m in diam. open‐top field chambers and exposed to charcoal‐filtered (CF) air at 350 µL CO 2 L −1 ; CF air + 150 µL CO 2 L −1 ; nonfiltered (NF) air + 35 n L O 3 L −1 ; and NF air + 35 n L O 3 L −1 + 150 µL CO 2 L −1 at two soil moisture levels from 1994 to 1996. The 150 µL CO 2 L −1 addition was 18 h d −1 and the 35 n L O 3 L −1 was 7 h d −1 from April until late October. In response to treatments, the Cr contents did not change significantly; however, participate, oxidizable, dissolved, humic ( C HA ) and fulvic ( C FA ) acid, and carbohydrate C pools increased in soils under CO 2 enrichment and well‐watered conditions but decreased under O 3 stress compared with soils under CF ambient air quality. Tropospheric CO 2 enrichment and well‐watered condition increased, and O 3 stress decreased the log optical density slope for both C HA and C FA fractions more than CF ambient air and restricted moisture treatment. Also, the E 465 / E 665 ratios of both C HA and C FA fractions were higher for the CO 2 enrichment and smaller for the O 3 stress compared with CF ambient air quality. Results suggest that tropospheric CO 2 enrichment and well‐watered conditions may favor an accumulation of low molecular weight and more aliphatic quality of C and O 3 stress favor high molecular weight and more aromatic quality of C.