Comparative Studies on the Physicochemical Properties of Mineral Soils in the Major Growing Areas of Sago Palm (Metroxylon sagu Rottb.) in Eastern Indonesia

The physicochemical properties of mineral soils in the major growing areas of sago palm in eastern Indonesia in the vicinity of Sentani near Jayapura, Papua Province (hereafter Jayapura); Kairatu, Seram Island, Maluku Province (Seram); and Kendari, Southeast Sulawesi Province (Kendari) were studied and compared. Soil samples of 0-15 cm and 15-30 cm depth were collected from every site, respectively, from September 2005 to January 2008. The results revealed that the average physicochemical properties of the soils from 0-30 cm depth in the areas where sago palm is grown varied depending on the site. The soil bulk densities were generally higher in Seram (1.35 g cm) than in Kendari (0.98 g cm) and Jayapura (0.89 g cm). The soil textures around Jayapura were dominated by silty loam. On the other hand, in Seram, the soil texture was dominated by silty loam and loam, and, around Kendari, it was dominated by sandy loam, loam, and silty clay. The averages of the soil pHs were slightly acid (6.4) in Jayapura and acid in both Seram (5.5) and Kendari (5.0). The amounts of total carbons (total-C) in Kendari were higher (30.5 g kg) than those in Jayapura (27.2 g kg) and Seram (9.9 g kg). Based on the averages of nutrient contents, including the CEC and the total-C, the sago-palm-growing areas showed the same trend in the order of Kendari > Jayapura > Seram in the CEC, total-N, and total-C. On the other hand, the exchangeable-K and the available-P indicated a trend in the order of Jayapura > Seram > Kendari. Variations in soil fertility, as in exchangeable-K, CEC, and total-N, among the soils collected in each area were higher in the order of Kendari > Jayapura > Seram. In addition, we discussed the relationship between the soil physicochemical properties and the reported growth parameters or starch productivity of sago palms grown in the same areas.