Linking above and belowground carbon sequestration, soil organic matter properties, and soil health in Brazilian Atlantic Forest restoration

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Bieluczyk, Wanderlei ; Asselta, Fernanda Ometto ; Navroski, Deisi ; Gontijo, Julia Brandao ; Venturini, Andressa Monteiro ; Mendes, Lucas William ; Simon, Carla Penha ; de Camargo, Plinio Barbosa ; Tadini, Amanda Maria ; -Neto, Ladislau Martin ; Bendassolli, Jose Albertino ; Rodrigues, Ricardo Ribeiro ; van der Putten, Wim H. ; Tsai, Siu Mui

• Document type: Journal article
• Source: Journal of Environmental Management; v. 344, p. 15-pg., 2023-07-15.

Abstract

Forest restoration mitigates climate change by removing CO2 and storing C in terrestrial ecosystems. However, incomplete information on C storage in restored tropical forests often fails to capture the ecosystem's holistic C dynamics. This study provides an integrated assessment of C storage in above to belowground subsystems, its consequences for greenhouse gas (GHG) fluxes, and the quantity, quality, and origin of soil organic matter (SOM) in restored Atlantic forests in Brazil. Relations between SOM properties and soil health indicators were also explored. We examined two restorations using tree planting ('active restoration'): an 8-year-old forest with green manure and native trees planted in two rounds, and a 15-year-old forest with native-planted trees in one round without green manure. Restorations were compared to reformed pasture and primary forest sites. We measured C storage in soil layers (0-10, 10-20, and 20-30 cm), litter, and plants. GHG emissions were assessed using CH4 and CO2 fluxes. SOM quantity was evaluated using C and N, quality using humification index (HLIFS), and origin using & delta;13C and & delta;15N. Nine soil health indicators were interrelated with SOM attributes. The primary forest presented the highest C stocks (107.7 Mg C ha-1), followed by 15- and 8-year-old restorations and pasture with 69.8, 55.5, and 41.8 Mg C ha-1, respectively. Soil C stocks from restorations and pasture were 20% lower than primary forest. However, 8- and 15-year-old restorations stored 12.3 and 28.3 Mg ha-1 more aboveground C than pasture. The younger forest had & delta;13C and & delta;15N values of 2.1 and 1.7 & PTSTHOUSND;, respectively, lower than the 15-year-old forest, indicating more C derived from C3 plants and biological N fixation. Both restorations and pasture had at least 34% higher HLIFS in deeper soil layers (10-30 cm) than primary forest, indicating a lack of labile SOM. Native and 15-year-old forests exhibited higher soil methane influx (141.1 and 61.9 & mu;g m-2 h-1). Forests outperformed pasture in most soil health indicators, with 69% of their variance explained by SOM properties. However, SOM quantity and quality regeneration in both restorations approached the pristine forest state only in the top 10 cm layer, while deeper soil retained agricultural degradation legacies. In conclusion, active restoration of the Atlantic Forest is a superior approach compared to pasture reform for GHG mitigation. Nonetheless, the development of restoration techniques to facilitate labile C input into deeper soil layers (>10 cm) is needed to further improve soil multifunctionality and long-term C storage. (AU)

• FAPESP's process: 19/25931-3 - Taxonomic and functional depiction of the microbial community involved in methane transformations in soils of the Brazilian Amazonia
• Grantee: Andressa Monteiro Venturini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 18/14974-0 - Dynamics of methane and sulfur microbial communities in Amazonian soils
• Grantee: Júlia Brandão Gontijo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/19000-4 - Applying the biotic soil legacy approach to understand positive-negative biota interactions for direct forest restoration from plant-soil communities feedbacks - BioFor
• Grantee: Tsai Siu Mui
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 19/16822-6 - Discovering the role of micro-organisms on ‘plant-soil feedback approach to assist the restoration of forest areas in the Atlantic Forest
• Grantee: Deisi Navroski
• Support Opportunities: Scholarships in Brazil - Doctorate