Changes in chemical attributes and fractions of organic matter in a Xanthic Ferralsol under different management systems

Examining organic matter fractions is crucial for comprehending variations in soil organic carbon (C) content resulting from the type of management used. The aim of this study was to assess the impact of management systems that utilize both organic and mineral fertilization on soil chemical attributes and organic matter fractions in the Xanthic Ferralsol. This study was conducted in the experimental areas of Embrapa Mandioca and Fruticultura, Cruz das Almas, Bahia State, Brazil. Three cassava and banana production systems, a conventional cassava cultivation system (CAS-CT), an organic banana system (BAN-ORG), and a conventional banana system (BAN-CT), were investigated using the native forest (NF) area as a reference. Soil sampling was conducted within the planting rows at depths of 0.0 - 0.10 and 0.10 - 0.20 m. Macronutrients, soil pH, soil total organic C, particulate organic C, light organic matter, labile-C, mineralizable C, and microbial biomass-C were assessed. BAN-ORG led to an increase in soil pH at both depths. Principal component (PC) analysis showed that organic cultivation was distinguished from the others owing to its strong correlation with soil bases (Ca and Mg), particulate organic C, and labile-C. In the NF and BAN-ORG soils, microbial-C levels in the 0.0 - 0.10 and 0.10 - 0.20 m layers remained consistent, whereas there was a reduction of 30 and 70% for CAS-CT and BAN-CT, respectively, with increasing depth. Mineralizable C (release of CO2-C) was higher in the NF and BAN-ORG systems than in the conventional system for both evaluated layers. BAN-CT and CAS-CT were strongly correlated with available potassium in PC-2, separating them from BAN-ORG and NF. Management practices implemented in the organic system resulted in an increase in macronutrient levels and a reduction in soil acidity. The elevation of labile-C and particulate organic C in the organic system increased the microbial activity in the soil, particularly in the subsurface layers. Organic management has emerged as a viable approach for enhancing organic C sequestration in the soil and creating favorable conditions for increasing microbial activity in banana cultivation.