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Continuous No‐Till Impacts on Soil Biophysical Carbon Sequestration
Author(s) -
Sundermeier A. P.,
Islam K. R.,
Raut Y.,
Reeder R. C.,
Dick W. A.
Publication year - 2011
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/sssaj2010.0334
Subject(s) - carbon sequestration , zoology , tillage , respiration , no till farming , biomass (ecology) , soil water , agronomy , soil respiration , environmental science , chemistry , soil science , carbon dioxide , biology , botany , soil fertility , organic chemistry
Increasing C sequestration through no‐till (NT) can reduce agricultural CO 2 emissions. However, for long‐term NT, information is lacking on the effect of biophysical C pools and processes on C sequestration. Composite soil samples taken at 7.5‐cm increments to a 30‐cm depth from conventionally tilled (CT) and 2 (NT 2 ), 23 (NT 23 ), and 44 yr (NT 44 ) of NT corn ( Zea mays L.) plots in northwest Ohio were analyzed. The microbial biomass (SMB) was 13, 83, and 86% higher in NT 2 , NT 23 , and NT 44 , respectively, than in CT. No‐till had slightly higher basal respiration rates but significantly lower specific maintenance respiration rates and SMB loss than CT. Aggregate stability in NT was 35 to 45% higher than in CT. Macroaggregate‐protected C (C MaA ) was 24, 80, and 92% higher in NT 2 , NT 23 , and NT 44 , respectively, than in CT. For all tillage treatments, these properties decreased with depth. The C sequestration rates for SMB were 22, 13, 7, and 3 kg ha −1 yr −1 at the 0‐ to 7.5‐, 7.5‐ to 15‐, 15‐ to 22.5‐, and 22.5‐ to 30‐cm depths, respectively for the first 10 yr of NT. During the same time, the C MaA sequestration rates were 92, 63, 47, and 37 kg ha −1 yr −1 at the four depths, and macroaggregate (MaA) formation rates were 3170, 350, 170, and 70 kg ha −1 yr −1 , respectively However, these rates decreased over the 44 yr of NT. By 20 yr of NT, at all depths the C sequestered in SMB reached a plateau. Similarly, C MaA sequestration plateaued at the surface by 20 yr and MaA formation at the surface leveled out by 10 yr.