As large-scale sago palm plantations expand, the study of the sago palm leaf area will assume increasing importance to manage the optimum density in sago plantations. In order to calculate the specific leaf area (SLA), which is one of the simple leaf area features, ten spineless-type palms at different phenological stages representing the entire life cycle of sago palm were selected. The analyses consisted of the calculation of the specific leaf area of individual leaves (SLA_L) and whole plants (SLA_P). The results showed that the SLA_L varied with the leaf number within a phenological stage without a consistent trend. However, the average SLA_L based on the leaf number showed a slight decreasing trend from younger to older leaves. The SLA_P also showed a decreasing trend from younger plants to older plants, which satisfactorily fitted a linear regression model.

View full abstract

 The physicochemical properties of soils from sago-palm-growing areas were studied and compared with the properties of the soils of surrounding cashew and cacao fields and the paddy fields around Kendari, Southeast Sulawesi Province, Indonesia. Soil samples were collected from 0-15 cm and 15-30 cm depth from Lalomasara and Lakomea in the Pohara Subdistrict, Watulondo in the Puwatu Subdistrict, and Konda in the Konda Subdistrict. The soil types in the sampled areas were mineral soil except for those in Watulondo, which were peat soil. The results revealed that the physicochemical properties of the mineral soils in the sago fields varied depending on the sites and kinds of crops being cultivated. The bulk densities ranged from 0.3-1.1 g cm^-3, and the texture varied from sandy loam to silty clay. The soil pH dominantly ranged from very acid to neutral. The nutrient contents of sago-palm-growing soils ranged from low to very high for total-N, very low to medium for available-P, low to medium for exchangeable-K, low to high for CEC, and low to very high for total-C content. The nutrient contents and pH of soils surrounding cashew and cacao were either lower or equal, but they were higher in bulk densities. However, higher total-C, N, and CEC and lower bulk density were observed in the neighboring paddy field than in sago palm fields due to the application of fertilizer and the straw incorporated into the soil every year. The pH in the peat soil in the sago-palm-growing areas ranged from very acid to acid, very high in CEC, organic-C, and total N contents, and low in available-P and exchangeable-K, with a bulk density of 0.3 g cm^-3. The effects of the soil physicochemical properties on the growth and starch production were discussed.

View full abstract

 Increasing biomass production based on the large-scale developments of farm field in unutilized lands is one of the global issues that must be examined under the current increasing demands for biomass. Large areas of unutilized land remain, such as the grass lands and flood plain in East Sepik Province, Papua New Guinea, with rich precipitation and adequate temperature. Sago palm is one of the crops adapted to the local environment in this region but is currently used only by the local people as their staple food on a small scale. This study advocates for the development of a comprehensive biomass production base that includes sago palm plantation. According to the result of satellite image analysis and Shuttle Radar Topography Mission data, the available grass land area is considered to be 200,000ha with a topography that changes from hilly to flat from north to south. The area near the flood plain of Sepik River is flat and low as a result of which water logging usually occurs in the rainy season. Pedological survey results show heavy clay distribution on a large part of the site. With regards to the topographic and pedological characteristics, a diversified plantation is an alternative idea for farm field extension. In such a plantation, each crop is planted in the zone with the most appropriate environmental conditions, sago palm being one such crop.

View full abstract

 To examine the effects of soil types [organic (OS) and mineral (MS) soils] and water regimes [W1: waterlogged, W2: making 10 holes (diameter: 1 cm) at even distances at the mid-height of the pot, and W3: making 5 holes of the same size at the bottom of the pot] on the early growth of sago palm seedlings, two pot experiments were conducted in Lalomasara, near Abelisawa village, District of Pohara Southeast Sulawesi Province, Indonesia from November 2006 to September 2007. The seedlings were grown under natural (nonprotected rainfall) conditions, and watering was done at least once every day. The soil water content was higher in OS than in MS and in the order of W1 > W2 > W3 in both type soils. The results showed few interaction effects of the two factors in the shoot and root growth and the macroelement uptake. The soil types had a lesser effect on the growth of seedlings than the water regimes, although the physicochemical properties of the soils were remarkably different. The water regimes affected the shoot base diameter significantly and tended to be larger, in the order of W1 > W2 > W3 plot, although other shoot growth parameters were not significantly affected by them. On the other hand, root growth was more affected by the water regimes than shoot growth, and a higher number of large roots (LR: > 5 mm in diameter) were observed in the W1 plot than in the W2 and W3 plots. The total LR length, the numbers of total medium-sized roots (MR: 2-5 mm in diameter) and upward roots of medium-sized roots (UR-MR) tended to be higher in the order of W1 > W2 > W3 plot. As a result, a higher root dry weight and shoot / root dry weight ratio were observed in the order of W1 > W2 > W3 and W3 > W2 > W1, respectively. The seedlings with a thicker base diameter of the shoot tended to have a longer total LR and a higher number of UR-MR.

View full abstract