Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping
Soil organic carbon (SOC) is declining globally due to intensification of agriculture. Reversing declines should reduce soil erosion, maintain yields, raise the soil’s atmospheric carbon sink, and improve habitat for biodiversity. Commercial fields were sampled in a diverse European Atlantic zone cr...
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doaj-d4b67a8e15c144feb0a01ebbca8485e82021-04-02T12:38:49ZengMDPI AGAgronomy2073-43952020-07-011097397310.3390/agronomy10070973Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable CroppingGeoffrey R. Squire0Mark Young1Linda Ford2Gillian Banks3Cathy Hawes4James Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, UKJames Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, UKJames Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, UKJames Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, UKJames Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland, UKSoil organic carbon (SOC) is declining globally due to intensification of agriculture. Reversing declines should reduce soil erosion, maintain yields, raise the soil’s atmospheric carbon sink, and improve habitat for biodiversity. Commercial fields were sampled in a diverse European Atlantic zone cropland to relate SOC status to cropping intensity and to define a realistic target for restoration. SOC (%C by mass) decreased from 4% to 2% as the proportion of high-intensity crops increased from zero to 55% (linear regression, F pr. < 0.001). In further sampling in and around high-intensity fields, mean SOC increased from 2.4% in cultivated soil to 3.3% in field margins and 4.8% in nearby uncultivated land (F pr. < 0.001). Three broad zones of SOC in close spatial proximity were then defined: 1) high-intensity arable from 1% to 3%, 2) mid-intensity arable and arable-grass from 3% to 5% and 3) uncultivated and semi-natural land from 5% upwards. C:N ratio was constrained around 12, unaffected by cropping intensity, but slightly lower in fields than in margins and uncultivated land (F pr. < 0.001). A feasible target SOC of just above 3% was defined for high-intensity sites. There should be no biophysical obstacle to raising SOC above 3% in the high-input sector. Results argue against treating cropland of this type as uniform: assessment and restoration should be implemented field by field.https://www.mdpi.com/2073-4395/10/7/973carbonnitrogenC:N ratiosoil organic carbonSOCintensified agriculture |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Geoffrey R. Squire Mark Young Linda Ford Gillian Banks Cathy Hawes |
spellingShingle |
Geoffrey R. Squire Mark Young Linda Ford Gillian Banks Cathy Hawes Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping Agronomy carbon nitrogen C:N ratio soil organic carbon SOC intensified agriculture |
author_facet |
Geoffrey R. Squire Mark Young Linda Ford Gillian Banks Cathy Hawes |
author_sort |
Geoffrey R. Squire |
title |
Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping |
title_short |
Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping |
title_full |
Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping |
title_fullStr |
Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping |
title_full_unstemmed |
Defining Targets for Reversing Declines of Soil Carbon in High-Intensity Arable Cropping |
title_sort |
defining targets for reversing declines of soil carbon in high-intensity arable cropping |
publisher |
MDPI AG |
series |
Agronomy |
issn |
2073-4395 |
publishDate |
2020-07-01 |
description |
Soil organic carbon (SOC) is declining globally due to intensification of agriculture. Reversing declines should reduce soil erosion, maintain yields, raise the soil’s atmospheric carbon sink, and improve habitat for biodiversity. Commercial fields were sampled in a diverse European Atlantic zone cropland to relate SOC status to cropping intensity and to define a realistic target for restoration. SOC (%C by mass) decreased from 4% to 2% as the proportion of high-intensity crops increased from zero to 55% (linear regression, F pr. < 0.001). In further sampling in and around high-intensity fields, mean SOC increased from 2.4% in cultivated soil to 3.3% in field margins and 4.8% in nearby uncultivated land (F pr. < 0.001). Three broad zones of SOC in close spatial proximity were then defined: 1) high-intensity arable from 1% to 3%, 2) mid-intensity arable and arable-grass from 3% to 5% and 3) uncultivated and semi-natural land from 5% upwards. C:N ratio was constrained around 12, unaffected by cropping intensity, but slightly lower in fields than in margins and uncultivated land (F pr. < 0.001). A feasible target SOC of just above 3% was defined for high-intensity sites. There should be no biophysical obstacle to raising SOC above 3% in the high-input sector. Results argue against treating cropland of this type as uniform: assessment and restoration should be implemented field by field. |
topic |
carbon nitrogen C:N ratio soil organic carbon SOC intensified agriculture |
url |
https://www.mdpi.com/2073-4395/10/7/973 |
work_keys_str_mv |
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