TY - JOUR
T1 - Soil macroaggregation drives sequestration of organic carbon and nitrogen with three-year grass-clover leys in arable rotations
AU - Guest, Emily J.
AU - Palfreeman, Lucy J.
AU - Holden, Joseph
AU - Chapman, Pippa J.
AU - Firbank, Les G.
AU - Lappage, Martin G.
AU - Helgason, Thorunn
AU - Leake, Jonathan R.
N1 - Funding Information:
The field design sampled for use in this study was part of the NERC Soil Security Programme funded project ‘SoilBioHedge’ (NE/M017044/1, NE/M017095/1, NE/M017079/1). Emily Guest's PhD is funded by the White Rose BBSRC DTP in Mechanistic Biology (BB/M011151/1). Lucy Palfreeman was funded by the Sheffield Undergraduate Research Experience (SURE) scheme funded by the BBSRC Research Experience Placement Scheme. We are thankful for Irene Johnson, Dave Johnson, Anthony Turner and Roscoe Blevins for their help in the laboratory and Hetty Shaw for the use of her bulk density measurements presented in her master's thesis work.
Funding Information:
The field design sampled for use in this study was part of the NERC Soil Security Programme funded project ‘SoilBioHedge’ (NE/M017044/1, NE/M017095/1, NE/M017079/1). Emily Guest's PhD is funded by the White Rose BBSRC DTP in Mechanistic Biology ( BB/M011151/1 ). Lucy Palfreeman was funded by the Sheffield Undergraduate Research Experience (SURE) scheme funded by the BBSRC Research Experience Placement Scheme. We are thankful for Irene Johnson, Dave Johnson, Anthony Turner and Roscoe Blevins for their help in the laboratory and Hetty Shaw for the use of her bulk density measurements presented in her master’s thesis work.
Publisher Copyright:
© 2022 The Authors
PY - 2022/12/15
Y1 - 2022/12/15
N2 - Conventional arable cropping with annual crops established by ploughing and harrowing degrades larger soil aggregates that contribute to storing soil organic carbon (SOC). The urgent need to increase SOC content of arable soils to improve their functioning and sequester atmospheric CO2 has motivated studies into the effects of reintroducing leys into long-term conventional arable fields. However, effects of short-term leys on total SOC accumulation have been equivocal. As soil aggregation may be important for carbon storage, we investigated the effects of arable-to-ley conversion on cambisol soil after three years of ley, on concentrations and stocks of SOC, nitrogen and their distributions in different sized water-stable aggregates. These values were benchmarked against soil from beneath hedgerow margins. SOC stocks (0–7 cm depth) rose from 20.3 to 22.6 Mg ha−1 in the arable-to-ley conversion, compared to 30 Mg ha−1 in hedgerows, but this 2.3 Mg ha−1 difference (or 0.77 Mg C ha−1 yr−1) was not significant). However, the proportion of large macroaggregates (> 2000 μm) increased 5.4-fold in the arable-to-ley conversion, recovering to similar abundance as hedgerow soils, driving near parallel increases in SOC and nitrogen within large macroaggregates (5.1 and 5.7-fold respectively). The total SOC (0–7 cm depth) stored in large macroaggregates increased from 2.0 to 9.6 Mg ha−1 in the arable-to-ley conversion, which no longer differed significantly from the 12.1 Mg ha−1 under hedgerows. The carbon therefore accumulated three times faster, at 2.53 Mg C ha−1 yr−1, in the large macroaggregates compared to the bulk soil. These findings highlight the value of monitoring large macroaggregate-bound SOC as a key early indicator of shifts in soil quality in response to change in field management, and the benefits of leys in soil aggregation, carbon accumulation, and soil functioning, providing justification for fiscal incentives that encourage wider use of leys in arable rotations.
AB - Conventional arable cropping with annual crops established by ploughing and harrowing degrades larger soil aggregates that contribute to storing soil organic carbon (SOC). The urgent need to increase SOC content of arable soils to improve their functioning and sequester atmospheric CO2 has motivated studies into the effects of reintroducing leys into long-term conventional arable fields. However, effects of short-term leys on total SOC accumulation have been equivocal. As soil aggregation may be important for carbon storage, we investigated the effects of arable-to-ley conversion on cambisol soil after three years of ley, on concentrations and stocks of SOC, nitrogen and their distributions in different sized water-stable aggregates. These values were benchmarked against soil from beneath hedgerow margins. SOC stocks (0–7 cm depth) rose from 20.3 to 22.6 Mg ha−1 in the arable-to-ley conversion, compared to 30 Mg ha−1 in hedgerows, but this 2.3 Mg ha−1 difference (or 0.77 Mg C ha−1 yr−1) was not significant). However, the proportion of large macroaggregates (> 2000 μm) increased 5.4-fold in the arable-to-ley conversion, recovering to similar abundance as hedgerow soils, driving near parallel increases in SOC and nitrogen within large macroaggregates (5.1 and 5.7-fold respectively). The total SOC (0–7 cm depth) stored in large macroaggregates increased from 2.0 to 9.6 Mg ha−1 in the arable-to-ley conversion, which no longer differed significantly from the 12.1 Mg ha−1 under hedgerows. The carbon therefore accumulated three times faster, at 2.53 Mg C ha−1 yr−1, in the large macroaggregates compared to the bulk soil. These findings highlight the value of monitoring large macroaggregate-bound SOC as a key early indicator of shifts in soil quality in response to change in field management, and the benefits of leys in soil aggregation, carbon accumulation, and soil functioning, providing justification for fiscal incentives that encourage wider use of leys in arable rotations.
U2 - 10.1016/j.scitotenv.2022.158358
DO - 10.1016/j.scitotenv.2022.158358
M3 - Article
SN - 0048-9697
VL - 852
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 158358
ER -