Organic fertilisation of orchard soils can influence soil organic matter (SOM), nutrient cycling, greenhouse gas emissions and the overall sustainability of the farming systems. This study investigated the long-term effects of organic citrus farming on soil properties in a semi-arid region of Cear & aacute;, Brazil. Soil samples were collected from a 30-year-old organic citrus orchard and a natural vegetation site was used as a reference. Management practices at the organic orchard include annual pruning, with residues left in the inter-row area and an annual application of 20 kg of on-site produced compost per plant in the planting rows. The organic compost is composed of cattle manure, sugarcane bagasse, rock phosphate, MB-4, EM-4 and molasses. We evaluated the SOM, oxidizable fractions of organic carbon and microbial activity in the orchard rows, inter-rows and the reference site. The highest carbon stocks (64.30 Mg ha-1 +/- 5.29; 0.0-1.00 m depth) were recorded in the inter-row soils. Microbial activity, however, was greatest in the soil at the natural vegetation site (52.34 +/- 2.19 mg CO2 kg-1) compared to the row soil (29.86 +/- 2.57 mg CO2 kg-1), with the inter-row showing intermediate values (41.21 +/- 7.04 mg CO2 kg-1). Overall, the results indicate that long-term organic management enhances carbon stocks and organic matter in sandy soil, supporting its potential for climate change mitigation and sustainable agriculture in semi-arid regions.