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Research article - Peer-reviewed, 2021

Soil dissolved organic carbon responses to sugarcane straw removal

Gmach, Maria Regina; Kaiser, Klaus; Cherubin, Mauricio Roberto; Cerri, Carlos Eduardo Pellegrino; Lisboa, Izaias Pinheiro; Vasconcelos, Ana Luisa Soares; Siqueira-Neto, Marcos

Abstract

Global demand for bioenergy increases interest in biomass-derived fuels, as ethanol from sugarcane straw. However, straw is the main carbon source to soil and its removal reduces C input, affecting active fractions (dissolved organic carbon, DOC) and C storage. To quantify the effects of straw removal on DOC and C stocks, we built lysimeter system using soil (Rhodic Kandiudox) from sugarcane field. We evaluated four soil depths (1, 20, 50 and 100 cm) and four straw removal rates: no removal NR, medium MR, high HR and total TR, leaving 12, 6, 3 and 0 Mg/ha on the soil surface, respectively. After rainfall, drainage water was collected and analysed for DOC content. Soil C stocks were determined after the 17-month. Total DOC released at 1-cm depth amounted to 606, 500, 441 and 157 kg/ha in NR, MR, HR and TR, respectively. Net-DOC suggests straw as the main source of DOC. Most of DOC in NR (50%) was retained within the 1-20 cm layer, resulting in higher C stock (10 Mg/ha) in the topsoil. In HR and MR, DOC retention was higher within 20-50 cm, suggesting differences in DOC composition. DOC in TR was 40% higher at 20 cm than at 1 cm, indicating C losses from topsoil. Low concentrations of DOC were found at 100-cm depth, but representing 30% in TR. Straw removal for bioenergy production is sustainable, but we should leave at least 3 Mg/ha of straw to ensure DOC production and soil C storage, taking account the DOC contribution to key soil functions.

Keywords

crop management; soil carbon storage; soil organic matter; tropical soils

Published in

Soil Use and Management
2021, volume: 37, number: 1, pages: 126-137
Publisher: WILEY

Authors' information

Gmach, Maria
Swedish University of Agricultural Sciences, Department of Ecology
Gmach, Maria
University of Sao Paulo
Kaiser, Klaus
Martin Luther University Halle Wittenberg
Cherubin, Mauricio Roberto
Universidade de Sao Paulo
Cerri, Carlos Eduardo Pellegrino
Universidade de Sao Paulo
Lisboa, Izaias Pinheiro
Universidade de Sao Paulo
Vasconcelos, Ana Luisa Soares
Universidade de Sao Paulo
Siqueira-Neto, Marcos
Universidade de Sao Paulo

Sustainable Development Goals

SDG7 Affordable and clean energy

UKÄ Subject classification

Soil Science

Publication Identifiers

DOI: https://doi.org/10.1111/sum.12663

URI (permanent link to this page)

https://res.slu.se/id/publ/108701