TY - JOUR

T1 - Dissolved carbon leaching from an Irish cropland soil is increased by reduced tillage and cover cropping

AU - Walmsley, David C.

AU - Siemens, Jan

AU - Kindler, Reimo

AU - Kirwan, Laura

AU - Saunders, Matthew

AU - Kaupenjohann, Martin

AU - Osborne, Bruce A.

AU - Kaiser, Klaus

PY - 2011/8

Y1 - 2011/8

N2 - Reduced tillage and cover cropping are often considered as measures to increase carbon sequestration in cropland soils. We hypothesized that these management practices could result in an increase in carbon leaching. To examine this possibility we assessed carbon leaching from an Irish arable soil under spring barley, either with conventional management or non-inversion tillage plus cover cropping. Concentrations of biogenic dissolved inorganic carbon (DIC) were considerably higher under reduced tillage probably due to a higher supersaturation of soil solution with respect to partial pressures of CO2 in soil air resulting from a reduced abundance of tillage-induced macropores. Leaching losses of DOC equalled 3 ± 0.3 g m−2 yr−1 for conventional management as well as for non-inversion tillage plus cover cropping. Losses of biogenic DIC were 14.5 ± 4.4 g m−2 yr−1 for conventional tillage and 34.0 ± 4.7 g m−2 yr−1 for non-inversion tillage plus cover crop. Higher leaching losses from the non-inversion tillage plus cover crop plot thereby reduced potential soil carbon gains by 20 g m−2 yr−1 compared to the conventionally managed treatment highlighting the need to consider leaching losses in estimates of carbon sequestration, especially if these are deduced from balancing carbon inputs and outputs.

AB - Reduced tillage and cover cropping are often considered as measures to increase carbon sequestration in cropland soils. We hypothesized that these management practices could result in an increase in carbon leaching. To examine this possibility we assessed carbon leaching from an Irish arable soil under spring barley, either with conventional management or non-inversion tillage plus cover cropping. Concentrations of biogenic dissolved inorganic carbon (DIC) were considerably higher under reduced tillage probably due to a higher supersaturation of soil solution with respect to partial pressures of CO2 in soil air resulting from a reduced abundance of tillage-induced macropores. Leaching losses of DOC equalled 3 ± 0.3 g m−2 yr−1 for conventional management as well as for non-inversion tillage plus cover cropping. Losses of biogenic DIC were 14.5 ± 4.4 g m−2 yr−1 for conventional tillage and 34.0 ± 4.7 g m−2 yr−1 for non-inversion tillage plus cover crop. Higher leaching losses from the non-inversion tillage plus cover crop plot thereby reduced potential soil carbon gains by 20 g m−2 yr−1 compared to the conventionally managed treatment highlighting the need to consider leaching losses in estimates of carbon sequestration, especially if these are deduced from balancing carbon inputs and outputs.

KW - Ecosystems Research

KW - DOC

KW - DIC

KW - Carbon sequestration

KW - Tillage

KW - Net ecosystem carbon balance

KW - Conservation agriculture

UR - http://www.scopus.com/inward/record.url?scp=80051582149&partnerID=8YFLogxK

U2 - 10.1016/j.agee.2011.06.011

DO - 10.1016/j.agee.2011.06.011

M3 - Journal articles

VL - 142

SP - 393

EP - 402

JO - Agriculture, Ecosystems and Environment

JF - Agriculture, Ecosystems and Environment

SN - 0167-8809

IS - 3-4

ER -