CHANGE IN PADDY-SOIL PROPERTIES OF LOWLAND IN AN GIANG PROVINCE, VIET NAM

Abstract

After rice cultivation, paddy soil properties could be changed toward a negative direction if applied with inappropriate cultivation regime. Soil samples distributed over 279.310 ha of paddy lowland in An Giang province were taken in 2010 and 2016 to examine the changes in some properties, including particle size distribution, bulk density, pH_KCL, total organic matter (OM, %), cation exchange capacity (CEC, cmole(+)/kg), and total N, P₂O₅, K₂O concentration. The values of these properties were shown on a GIS-based map using the ArcGIS. The results showed that almost all examined soil properties decreased after six-year paddy rice cultivation with different magnitudes. The highest decrease was observed on soil CEC, decreased by 5.59 cmol(+)/kg for a corresponding paddy area equivalent 82% of total examined area. It was followed by OM concentration (decreased by 0.84%) and pH_KCL (decreased by 0.88), for the areas equivalent 11% and 52% of the total examined area, respectively. The decreasing tendency in soil properties of the paddy lowland in An Giang province may suggest that the applied cultivation regime could be inappropriate and that it should be improved for a sustainable development.