Dados do Trabalho

Título

TESTING THE POTENTIAL OF INTEGRATED SYSTEMS AS A NATURE-BASED SOLUTION FOR SOIL CARBON STABILIZATION

Resumo

The cultivation of forage species with vigorous root growth such as brachiaria grass (Brachiaria brizantha) in well-managed pastures and integrated cropping systems can be an effective strategy to increase soil carbon (C) sequestration for climate change mitigation. The main objectives were to assess the changes in soil C quantity and quality, and understand the mechanisms of soil C stabilization under integrated systems. A field experiment was conducted for >10 years in a randomized block design with four replications in an Oxisol with clay texture at Sinop/MT−Brazil, and four treatments were tested: Crop Succession –CS, Integrated Crop-Livestock –ICL, Integrated Crop-Livestock-Forest –ICLF, and Pasture –P. Soil samples were collected at surface layer, and the total C concentration was quantified by dry combustion, aggregate stability was analyzed by wet-sieving, and the surface chemical composition was quantified by x-ray photoelectron spectroscopy (XPS). Our findings revealed that ICL and P systems presented 33% higher soil C stocks compared to both ICLF and CS. Higher values of the mean weight diameter of aggregates (MWD) were observed under ICL and P, and they were positively correlated with soil C stocks. The high-resolution C spectra showed a notable increase in the relative abundance of C−C/C=C bonding in soils under P and ICL by 17 and 9% compared to both ICLF and CS, respectively, while an increased abundance of the C associated with oxygen (C−O, −C=O, −O−C=O) was observed under P and ICL by 25%, and ICLF by 14% compared to CS. In the ICLF, all results from the position below the eucalyptus rows were similar to the CS system, and the central position of the area were similar to ICL and P. These findings suggest that ICL and P systems play an important role in soil C sequestration by increasing soil aggregation, C storage and chemical stability, providing a fundamental scientific basis for a comprehensive understanding of soil C stabilization processes.

Palavras-chave

integrated crop-livestock; soil carbon sequestration; soil aggregation; XPS; brachiaria.

Instituição financiadora

This research was supported by RCGI (FAPESP process #2020/15230-5), National Council for Scientific and Technological Development – CNPq (proc 150892/2022-5), and Sao Paulo Research Foundation – FAPESP (grants 2022/07665-7).

Agradecimentos

FAPESP, CNPq, SHELL, RCGI

Área

Divisão 3 – Uso e Manejo do Solo: Comissão 3.3 – Manejo e Conservação do Solo e da Água