Soil Degradation due to Long-term Citrus Cultivation in the Upper Vietnamese Mekong Delta

Abstract

This study investigated the impact of tree age on soil properties in citrus orchards in the upper Vietnamese Mekong Delta province, examining orchards of four age groups (<10, 10–20, 21–30, and over 30 years) at two soil depths (0–20 cm and 20–50 cm). Findings indicate notable variations in soil physicochemical properties with age and depth. In older orchards (over 20 years), bulk density increased and soil pH decreased, with overall low pH values (3.5–5.0) observed. Electrical conductivity remained consistent across all ages. Key nutrients such as nitrogen (N), phosphorus (P), potassium (K), soil organic carbon (SOC), and cation exchange capacity (CEC) generally decreased with the age of the orchards. These trends were consistent across both soil layers. The study highlights the influence of prolonged cultivation on soil health and provides insights for developing strategies to enhance productivity and sustain agricultural practices in citrus orchards.