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Available Carbon Released from Crop Roots During Growth as Determined by Carbon‐13 Natural Abundance
Author(s) -
Qian Jin H.,
Doran John W.
Publication year - 1996
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1996.03615995006000030021x
Subject(s) - biomass (ecology) , environmental science , agronomy , abundance (ecology) , growing season , crop , greenhouse , carbon fibers , soil carbon , vegetation (pathology) , soil water , chemistry , soil science , biology , mathematics , ecology , medicine , algorithm , pathology , composite number
Quantifying plant contributions to root‐zone available C during the growing season is important for better understanding of microbial processes regulating N cycling. However, it is difficult to determine root‐derived available C under conditions that better reflect plant growth in the field. We proposed an approach using 13 C natural abundance in soil with a history of C 3 vegetation, which is planted to a C 4 plant, to estimate the contribution of C 4 root‐derived C to soil microbial biomass by measuring the δ 13 C change in microbial biomass C during crop growth. In a pilot greenhouse study using this approach with large‐diameter (30.5 cm) repacked soil cores, we estimated that 48 and 121 kg C ha −1 of root‐derived available C was produced, which accounted for 16 and 13% of total C 4 ‐C entering the soil during 5 and 10 wk growth of corn ( Zea mays L.), respectively. Similarly, 88, 283, and 402 kg C ha −1 of root‐derived available C from corn were estimated at 4, 8, and 16 wk, respectively, in a repeated experiment. Thus, the 13 C natural abundance signals in microbial biomass can provide a practical and reliable way to assess available C released from plant roots during growth.