Soil degradation and recovery - Changes in organic matter fractions and structural stability.
Geoderma
; 364: 114181, 2020 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-32255839
ABSTRACT
The combination of concurrent soil degradation and restoration scenarios in a long-term experiment with contrasting treatments under steady-state conditions, similar soil texture and climate make the Highfield land-use change experiment at Rothamsted Research unique. We used soil from this experiment to quantify rates of change in organic matter (OM) fractions and soil structural stability (SSS) six years after the management changed. Soil degradation included the conversion of grassland to arable and bare fallow management, while soil restoration comprised introduction of grassland in arable and bare fallow soil. Soils were tested for clay dispersibility measured on two macro-aggregate sizes (DispClay 1-2 mm and DispClay 8-16 mm) and clay-SOM disintegration (DI, the ratio between clay particles retrieved without and with SOM removal). The SSS tests were related to soil organic carbon (SOC), permanganate oxidizable C (POXC) and hot water-extractable C (HWC). The decrease in SOC after termination of grassland was greater than the increase in SOC when introducing grassland. In contrast, it was faster to restore degraded soil than to degrade grassland soil with respect to SSS at macro-aggregate scale. The effect of management changes was more pronounced for 8-16 mm than 1-2 mm aggregates indicating a larger sensitivity towards tillage-induced breakdown of binding agents in larger aggregates. At microscale, SSS depended on SOC content regardless of management. Soil management affected macroscale structural stability beyond what is revealed from measuring changes in OM fractions, underlining the need to include both bonding and binding mechanisms in the interpretation of changes in SSS induced by management.
A, Arable; AG, Arable converted to grass; BF, Bare fallow; CEC, Cation exchange capacity; DI, Clay-SOM disintegration; DispClay 12 mm, Clay dispersibility of 12 mm aggregates; DispClay 816 mm, Clay dispersibility of 816 mm aggregates; E, Young's modulus; Esp, Mass-specific rupture energy; G, Grass; GA, Grass converted to arable; GBF, Grass converted to bare fallow; HWC, Hot water-extractable carbon; POXC, Permanganate oxidizable carbon; Rate of change; SSA, Specific surface area; SSS, Soil structural stability; Soil degradation; Soil management; Soil organic carbon; Soil restoration; Soil structural stability; Y, Tensile strength
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MEDLINE
Idioma:
En
Ano de publicação:
2020
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Article