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Free‐air Carbon Dioxide Enrichment of Wheat: Soil Carbon and Nitrogen Dynamics
Author(s) -
Prior S. A.,
Torbert H. A.,
Runion G. B.,
Rogers H. H.,
Wood C. W.,
Kimball B. A.,
LaMorte R. L.,
Pinter P. J.,
Wall G. W.
Publication year - 1997
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/jeq1997.00472425002600040031x
Subject(s) - mineralization (soil science) , loam , calcareous , carbon dioxide , chemistry , soil respiration , soil carbon , nitrogen , environmental chemistry , nitrogen cycle , agronomy , incubation , respiration , total organic carbon , zoology , soil water , environmental science , soil science , botany , biology , organic chemistry , biochemistry
The predicted positive impact of elevated atmospheric carbon dioxide (CO 2 ) concentration on crop biomass production suggests that more C will reach the soil. An aspect of soil C sequestration that requires further study is the effect of elevated CO 2 on C and N dynamics; this relationship is the key to understanding potential long‐term C storage in soil. Soil samples (0–5, 5–10, and 10–20 cm increments) were collected after 2 yr of wheat ( Triticum aestirum L.) production under two CO 2 levels [370 (ambient) and 550 µL L −1 (free‐air CO 2 enrichment)(FACE)] and two water treatments [100% of ET replaced (wet) and 50% of ET replaced (dry)] on a Trix clay loam [fine, loamy, mixed (calcareous), hyperthermic Typic Torrifluvents] at Maricopa, AZ. Organic C, total N, potential C and N mineralization, and C turnover were determined during a 60‐d incubation study. Organic C content increased at all three soil depths under FACE and the total N content increased at the 5 to 10 and 10 to 20 cm depths. In general, increased N mineralization under dry conditions corresponded well with patterns of higher C mineralization and turnover. Nitrogen mineralization was unaffected by CO 2 treatment, indicating that factors other than N may limit C mineralization and turnover. Soil respiration and C turnover patterns were not affected by CO 2 treatment level at the 0 to 5 cm depth; however, these measures were lower under FACE at the lower depths. Soil respiration and C turnover at the 10 to 20 cm depth were increased by water stress under ambient CO 2 ; these measures under both water levels for FACE were similar to the ambient CO 2 /wet treatment, suggesting that more C storage in wheat cropping systems is likely under elevated CO 2 regardless of water treatment.