The study aimed to determine and characterize the physicochemical properties of rice soil in the triple, double, and single rice-upland crops in Vinh Long province, Vietnam. The results showed that rice cultivation soil in Vinh Long province had a relatively low pH (4.3–5.4). Most of the physical parameters in the soil were within limits suitable for plant growth. Electrical conductivity (EC), total dissolved salts, and exchanged aluminum (Al3+) in the soil were in normal ranges. The total cation exchange and zinc were not in the practical ranges for plant growth. Total nitrogen (TN), total phosphorus (TP), total potassium (TK), and total organic matter (OM) content ranged from moderate to good, rich, medium to poor, and rich, respectively. Potassium (K+), sodium (Na+), calcium (Ca2+), and magnesium (Mg2+) were the exchange base cations in the soil that were present in low, medium, and high concentrations, respectively. Manganese (Mn) content was suitable for plant growth. Interestingly, the highest concentrations of OM, TP, exchangeable base cations, and Mn were found in the soil of triple rice, while the highest TN and TK content was found in a single rice-upland crop. As a result of the cluster analysis, it was possible to reduce the number of soil sample monitoring sites from 13 to 5 to guarantee the representativeness of the physiochemical characteristics of the soil in the study area. The results also showed that the soil quality of different rice-based soils was disparity mainly due to exchanged Al3+, EC, soil structure, and density. The present findings provide useful scientific information for sustainable soil management in agricultural production in the study area.
Key words: Soil quality; rice; upland; cluster analysis; Vinh Long
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