Soil organic C affected by dry-season management of no-till soybean crop rotations in the tropics

Author(s)

Rigon, Joao Paulo Gonsiorkiewicz ^[1] ; Calonego, Juliano Carlos ^[1] ; Capuani, Silvia ^[2] ; Franzluebbers, Alan J. ^[3]

Affiliation

^[1] Sao Paulo State Univ, Coll Agr Sci, Dept Crop Sci, UNESP, 3780 Ave Univ, Botucatu, SP - Brazil

^[2] Sao Paulo State Univ, Coll Agr Sci, Dept Soil Sci, UNESP, 3780 Ave Univ, Botucatu, SP - Brazil

^[3] North Carolina State Univ, Dept Crop & Soil Sci, USDA ARS, Raleigh, NC - USA

• Document type: Journal article
• Source: PLANT AND SOIL; v. 462, n. 1-2 FEB 2021.
• Web of Science Citations: 0

Abstract

Aims Cover crop species selection for soybean (Glycine max) production under no-tillage (NT) management may affect soil organic C sequestration by altering the quantity and quality of C inputs, thereby affecting cropping system sustainability. If so, the underlying mechanisms for such regulation are still unclear. Methods We assessed changes in soil C and N fractions at 0-0.1 m depth and soil C stock at 0-0.6 m depth during the last three years of dry-season cover cropping in a soybean production system managed with NT for 9 years on a Rhodic Hapludox in Sao Paulo, Brazil. Dry-season management treatments were repeated yearly in a split-plot scheme. Main plots during the fall-winter were (1) ruzigrass (Urochloa ruziziensis), (2) grain sorghum (Sorghum bicolor), and (3) the intercropping of ruzigrass and sorghum. Subplots during spring prior to planting soybean were (a) pearl millet (Pennisetum glaucum), (b) sunn hemp (Crotalaria juncea), and (c) forage sorghum (Sorghum bicolor). Results Soil C and N fractions were affected according to crop residue characteristics of the rotations. Higher soil C stocks in 2012 and 2015 (7 % an average) were observed at 0.2-0.4 m depth by ruzigrass compared to sorghum. High crop residue input with ruzigrass in the fall-winter sequestered 0.61 Mg C ha(- 1) yr(- 1) at 0-0.1 m soil depth compared with lower C sequestration using grain sorghum (0.29 Mg C ha(- 1) yr(- 1)). Conclusions The quantity and quality of crop residues impact its retention on soil surface controlling the dynamics of soil C and N fractions and can be considered relevant for soil C sequestration. These aspects could contribute to the mitigation of atmospheric CO2 in crop production systems. (AU)

• FAPESP's process: 13/23359-4 - Management systems and crop sequences as determinants in the amount and quality of the soil organic matter.
• Grantee: João Paulo Gonsiorkiewicz Rigon
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/23029-5 - FORMS OF PHOSPHORUS IN LONG-TERM PRODUCTION SYSTEMS
• Grantee: João Paulo Gonsiorkiewicz Rigon
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/23389-6 - Crop residues in rotations systems as determinants of soil aggregate fractionation and C and N mineralization
• Grantee: João Paulo Gonsiorkiewicz Rigon
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate