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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #420162

Research Project: Agricultural Management for Long-Term Sustainability and Soil Health

Location: Soil Management and Sugarbeet Research

Title: Soil carbon allocation, composition, and sequestration changes induced by cropping diversification in tropical systems

Author
item LOCATELLI, JORGE - Federal University Of Sao Paulo
item SILVA SANTOS, RAFAEL - Colorado State University
item TENELLI, SARAH - Brazilian Biorenewable National Laboratory
item SOARES, MATHEUS - Federal University Of Sao Paulo
item Del Grosso, Stephen
item Stewart, Catherine
item POPIN, GUSTAVO - Federal University Of Sao Paulo
item ZEN BERTOL, FELIPE - Universidade Federal Do Mato Grosso Do Sul
item CARVALHO, JOAO - Brazilian Biorenewable National Laboratory
item CHERIBUN, MAURICIO - Federal University Of Sao Paulo
item CERRI, CARLOS - Federal University Of Sao Paulo

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Physical protection of carbon (C) inside soil particles can store C and improve soil health. However, little is known about how cropping diversification strategies affect C protection in tropical soils. We investigated how crop rotation complexity and cover crops affect soil properties in Mato Grosso, Brazil. Compared to typical soybean-maize cropping, more complex systems that included cover crops had higher soil C and nutrient levels. Results revealed that cropping diversification is an effective strategy for increasing C protection and enhancing heath of tropical soils.

Technical Abstract: Physical protection by carbon (C) occlusion inside soil aggregates is assumed to be a key mechanism of C stabilization. Nevertheless, little is known about how cropping diversification strategies affect C allocation and protection in soil aggregates and their stability, especially in highly weathered tropical soils. This study evaluated how cropping diversification strategies based on cover crops and no-tillage affect soil organic matter (SOM) storage and aggregation in a tropical clayey Oxisol. Changes in soil C and nitrogen (N) stocks, soil aggregate stability, C allocation within aggregates, and C speciation within aggregate classes using spectroscopy analysis were quantified. Soil C and N stocks under the most complex crop systems with cover crops increased by ~20% and 29%, respectively, compared to soybean-maize double cropping. The systems including cover crops also increased soil aggregate stability, doubling large macroaggregation in the 5-10 and 10-20 cm depths compared to the soybean-maize double cropping. Increased aggregation under cover crops enhanced C contents within aggregates, i.e., ~48%, 32%, and 34% higher for large macroaggregates, macroaggregates, and microaggregates, respectively, compared to soybean-maize double cropping (average considering different layers and cover cropping systems). Spectroscopy analysis showed that the diverse cropping systems increased the aromatic C fraction (i.e., C=C/C–C) in large macroaggregates from the 0-5 cm layer while reducing oxidized groups, i.e., C=O/O–C=O and C–O. Overall, results revealed that cropping diversification is an effective strategy for increasing soil aggregate stability and physical protection of C (especially aromatic), and therefore can promote C storage in tropical soils.