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Legacy effects of grassland management on soil carbon to depth
Author(s) -
Ward Susan E.,
Smart Simon M.,
Quirk Helen,
Tallowin Jerry R. B.,
Mortimer Simon R.,
Shiel Robert S.,
Wilby Andrew,
Bardgett Richard D.
Publication year - 2016
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.13246
Subject(s) - environmental science , soil carbon , soil water , carbon sequestration , grassland , carbon fibers , soil management , soil science , hydrology (agriculture) , agronomy , ecology , geology , carbon dioxide , biology , materials science , geotechnical engineering , composite number , composite material
Abstract The importance of managing land to optimize carbon sequestration for climate change mitigation is widely recognized, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large‐scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management. From a nationwide survey of grassland soils to 1 m depth, we show that carbon in grassland soils is vulnerable to management and that these management effects can be detected to considerable depth down the soil profile, albeit at decreasing significance with depth. Carbon concentrations in soil decreased as management intensity increased, but greatest soil carbon stocks (accounting for bulk density differences), were at intermediate levels of management. Our study also highlights the considerable amounts of carbon in subsurface soil below 30 cm, which is missed by standard carbon inventories. We estimate grassland soil carbon in Great Britain to be 2097 Tg C to a depth of 1 m, with ~60% of this carbon being below 30 cm. Total stocks of soil carbon (t ha −1 ) to 1 m depth were 10.7% greater at intermediate relative to intensive management, which equates to 10.1 t ha −1 in surface soils (0–30 cm), and 13.7 t ha −1 in soils from 30 to 100 cm depth. Our findings highlight the existence of substantial carbon stocks at depth in grassland soils that are sensitive to management. This is of high relevance globally, given the extent of land cover and large stocks of carbon held in temperate managed grasslands. Our findings have implications for the future management of grasslands for carbon storage and climate mitigation, and for global carbon models which do not currently account for changes in soil carbon to depth with management.