Palm oil is being criticized as an unsustainable product by the EU due to its association with deforestation and high carbon emissions. However, the producers in Indonesia do not acknowledge the criticisms. Therefore, this study aimed to compare the carbon footprint of a representative EU-produced vegetable oil, rapeseed oil, with Indonesian palm oil. The analysis is divided into two stages, namely (a) land use conversion (LUC) as well as (b) plantation and oil processing. LUC entailed the conversion of native vegetation, such as forest areas and grassland, to vegetable oil crops. The carbon opportunity cost was used to account for the LUC contribution to the carbon footprint. For plantation and oil processing stages, the LCA SIMAPRO was adopted. The results showed that when vegetable oil replaced high-carbon-storage vegetation such as forests, the LUC carbon footprint of rapeseed oil and palm oil production were 2.09 and 1.49 t CO₂eq t⁻¹ oil, respectively. Replacing low-carbon-storage vegetation, namely shrub/grassland, led to 0.05 and −0.43 t CO₂eq t⁻¹ of repressed and palm oils, respectively. Based on the LCA SIMAPRO, the carbon footprints of plantation and oil processing stages were 1.05 and 0.88 t CO₂eq t⁻¹ oil for rapeseed and palm oils, respectively. The cultivation of oil palm in peatland generated a higher total carbon footprint (i.e., combined LUC and plantation and oil processing stages) than rapeseed oil (13.8 to 3.14 t CO₂eq t⁻¹ oil). However, in non-peatland areas, the total carbon footprint of palm oil was lower than rapeseed oil (2.37 to 3.14 t CO₂eq t⁻¹ oil) when replacing tropical forest and temperate forest vegetation, respectively. The total footprint was 1.2 to 0.45 t CO₂eq t⁻¹ oil when both replaced shrub/grassland. The higher productivity of oil palm and lower fertilizer requirement contributed primarily to the lower carbon footprint in non-peatland areas.

The east coast of North Sumatra has lower rainfall than the central (Bukit Barisan) and the west coast. Meanwhile, the literature on the influence of climate phenomena, such as El Nino, La Nina, and positive/negative IOD, on the rainfall distribution in North Sumatra remains quite limited. This paper aims to describe the spatial distribution of seasonal rainfall on the east coast of North Sumatra and its correlation with ENSO and the IOD. Hopefully, the spatial analysis of seasonal rainfall and its correlation to ENSO and IOD can improve the understanding on rainfall distribution and the influenced factors in the study area. For 16 years (1999–2014), the monthly rainfall data at 52 rain gauge stations that passed the homogeneity test were divided into the seasonal 6-month and 4-month. Hereafter, the seasonal rainfall was spatially analyzed with the Inverse Distance Weighting (IDW) method using ArcMap software. The spatial analysis results can clearly describe the rainfall dynamics and its anomalies, therefore, can be more easily understood. The repetition of rainfall anomaly patterns can be seen in January to June (JFMAMJ), January to April (JFMA), and May to August (MJJA), which occurs in 3–4 years. Furthermore, the Pearson-correlation analysis shows that SOI has a strong positive correlation on JFMAMJ (0.529), JFMA (0.485), and MJJA (0.366), while IOD has a strong positive correlation on MJJA (0.512) and negative on September to December - SOND (-0.341).

The North Sumatera rainfall area is classified as equatorial type, which characterized by two peaks of maximum rainfall for each year and distribute evenly through the year with maximum 1 dry month. However, the occurrence of rainfall below normal in the period of January-April in 2014-2016 shows that there has been a change in rainfall patterns that can be caused by climate change. This paper aims to identify changes in rainfall patterns on the east coast of North Sumatera spatially and temporally. Over 16 years (1999–2014) monthly and annual rainfall data series in 74 locations along east coast of North Sumatera are selected for identifying the rainfall pattern change. The data was taken from private rain gauge and North Sumatra Agency for Meteorology, Climatology, and Geophysics (BMKG), which located along the east coast of North Sumatera. The observation on annual rainfall shows changes in rainfall patterns in the study sites would occur every 5-7 years. The occurrence of La Nina and El Nino also give a part on the change of annual rainfall pattern.

The water requirement of oil palm depends on the growth phase (e.g., higher demand during vegetative expansion), environmental conditions (e.g., increased under high vapour pressure deficit), and agricultural practices (e.g., reduced demand through effective water management). Therefore, the water used for oil palm nurseries should be used efficiently to preserve environmental sustainability. The main objective of this research was to determine the water use efficiency (WUE) of oil palm during the main nursery phase. The study evaluated several irrigation strategies inside and outside the greenhouse, including fixed daily watering (two liters per seedling), irrigation based on actual evapotranspiration (ETa), rainfall-dependent watering, and no irrigation. In the outdoor treatments, one group of seedlings was irrigated according to ETa, but watering was withheld when daily rainfall exceeded five mm, while another group received two liters per day only when rainfall was below five mm. These two treatments showed the highest daily evapotranspiration rates, greater vegetative growth, and higher biomass accumulation compared to the other treatments. Notably, the ETa-based treatment was recorded as having the highest water use efficiency (WUE). This study concludes that water loss during evapotranspiration is the main determining factor for irrigation volume. Therefore, irrigation in oil palm nurseries should be based on ETa to improve efficiency and lower costs. These findings offer practical guidance for farmers or plantation management to support more sustainable and cost-effective irrigation practices.

The big hole planting system for oil palm is one of the efforts to control the infection of Ganoderma boninense. The big hole method can also improve physical and chemical soil properties that affect the soil microbes population and in turn suppress the soil pathogens. However, the information about soil microbes population under the big hole planting method is still limited. This study aimed to compare the population of soil bacteria and fungi in soil samples from oil palm plantations that applied the big hole for 15 years and non big hole (standard) planting method. The population of bacteria and fungi was analyzed using the dilution plate method, while the calculation was based on the total plate count. Based on the results of statistical analysis (P-Value = 0.05), it is known that the mean population of bacteria is significantly different but the mean population of fungi is not significantly different between the big hole and non-big hole planting systems. The population of soil bacteria under the big hole and standard method was 1.6 x 106 cfu/g and 1.1 x 106 cfu/g, respectively. Meanwhile, the population of soil fungi under the big hole method was 9.7 x 104 cfu/g and 7.2 x 104 cfu/g under the standard planting method. Microorganisms in soil are considered important for maintaining soil health and quality, because various microorganisms are involved in important soil functions. In addition, high soil microbial populations will contribute to reducing soil base disease or suppression of soil pathogens.