Prospects for soil carbon storage on recently retired marginal farmland.

Autor: Mazzorato ACM; Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph N1G2W1, Ontario, Canada., Esch EH; Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph N1G2W1, Ontario, Canada., MacDougall AS; Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph N1G2W1, Ontario, Canada. Electronic address: asm@uoguelph.ca.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2022 Feb 01; Vol. 806 (Pt 3), pp. 150738. Date of Electronic Publication: 2021 Oct 02.
DOI: 10.1016/j.scitotenv.2021.150738
Abstrakt: Soil organic carbon (SOC) is strongly affected by farm cropping, which covers >10% of the earth's surface. Land retirement of marginal fields, now a global initiative, can increase SOC storage but reported accumulation rates are variable. Here, we quantify SOC in crop fields and retired marginal land in an intensely farmed 10,000 km 2 region of central North America, testing nutrients, soil texture and management as drivers of SOC storage. Overwhelmingly, SOC was associated with farm management with among-farm differences varying >fourfold (17.4-81 t ha -1) in the top 15 cm. Total farm SOC averaged 502.2 t farm -1 but again ranged widely (216-1611 t farm -1). Farm-specific SOC was often, but not always, higher on farms with N-rich silt-clay soils, and lower on sandy soils with higher P relating to former tobacco production. In contrast, within-farm SOC between crop fields and retired land did not significantly differ with time. Low SOC on retired lands was associated with persistently high soil N and P and elevated microbial respiration. Retired soils did possess substantially larger pools of lignin-rich root biomass to depths of 60 cm, which may signify eventual SOC accumulation possibly as nutrient legacies diminish. Our work shows that management legacy, interacting with soil texture and nutrients, predicts SOC more than short-term retirement. Indeed, crop fields averaged 67% of farm SOC because they represented up to 94% of total farm area - SOC retention on cropland remains a management priority, above and beyond gains with retirement. Interestingly, the largest per-volume SOC levels were in remnant forest that contained 25% of farm SOC despite only averaging 11% of farm area. Maintaining SOC stocks in farm landscapes may be more quickly attained by protecting remnant forest, with retired lands needing time to re-build SOC stocks.
Competing Interests: Declaration of competing interest We declare no conflict of interest.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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