Soil quality evaluation for navel orange production systems in central subtropical China

• As a weighting method for soil quality evaluations, MRA method was superior to PCA.
• Soil quality evaluations should be specific to crop and soil types.
• The MDS for navel orange orchards includes SOM, silt, pH, AB and AK.
• The use of lime, and organic, K, and B fertilizers is important in orchards.

Soil quality evaluations based on crop yields can provide clear guidance for managing agricultural production. Navel oranges are widely cultivated around the world. However, systematic soil quality evaluations for navel orange orchards have not been reported. This study uses two weighting methods, principle component analysis (PCA) and multiple regression analysis (MRA), to evaluate the soil quality of navel orange orchards in central subtropical China. The PCA weighting method is widely used for evaluating soil quality. In contrast, the MRA weighting method, which is linked closely with crop yield, is rarely used. A variety of soil samples, representing the spatial homogeneity in 114 navel orange orchards of Xinfeng County, Jiangxi province, were collected and analyzed for 17 frequently used chemical and physical properties. Result showed that the sensitivity and accuracy of the MRA weighting method were superior to those of the PCA weighting method. Thus, the MRA weighting method was recommended for future soil quality assessments. The soil indicators retained in the minimum data set (MDS) included SOM, silt, pH, AB and AK. The MDS indicators changed with the crop and soil types. Therefore, future soil quality evaluations should be specific to the crop and soil types. Overall, the soil quality of the studied navel orange orchards was low or moderate. Thus, more efforts should be directed towards adding lime and organic, potassium (K) and boron (B) fertilizer in navel orange production management.