SOIL QUALITY ASSESSMENT OF Pinus merkusii PLANTATION IN NORTH CENTRAL VIETNAM

Abstract

   Soil quality under Pinus merkusii plantation canopies in North Central Vietnam was assessed using a Soil Quality Index (SQI). The SQI was developed from a suite of soil physical, chemical, and biological indicators, including bulk density, particle-size distribution, pH_KCl, soil organic carbon (SOC), total nitrogen (N), available P₂O₅ and K₂O, cation exchange capacity (CEC), and microbial biomass carbon. Pearson correlation analysis and principal component analysis (PCA) were applied to examine relationships among indicators and to select a minimum data set (MDS). The results indicated that three representative indicators - sand content, SOC, and pH_KCl corresponding to three principal components were selected to construct the SQI. SQI values across the sampled stands ranged from 0.41 to 0.86, with a mean of 0.53, suggesting that soils under P. merkusii plantations in North Central Vietnam generally exhibit high soil quality. These findings can support rapid assessment and long-term monitoring of soil quality dynamics in plantation forests and provide a scientific basis for proposing sustainable soil management practices