No abstract

Clove is a superior crop and the main source of income for farmers in South Halmahera, especially in Bacan island. There is an increase in the clove planting area since 2013. However, clove productivity in 2017 decreased by 32% from 2013 to 2017. The factors that influence clove production are the environment and the soil condition. Clove plants to be able to grow and produce require specific growing environmental requirements. Environmental factors that influence clove plants include climate, height and type of soil. This study aims to analyze the suitability of land for clove plants on Bacan Island. Methods for collecting land resource data include primary data surveys and secondary data collection. The land suitability evaluation was carried out according to the limiting approach. The results of land suitability analysis at the subclass level in several districts in the Bacan Island for clove plants showed that the suitability of land suitability varied (S1, S2, S3, and N) between districts with limiting factors are erosion hazard and the effective depth roots.

This study aimed to obtain the composition of biochar as a soil enhancer and mycorrhizal dose, which affected the nutrient uptake of cayenne plants. This experimental research was based on a separate plot design (RPT) with a basic randomized block design (RCBD). The main plot experiment was vesicular-arbuscular mycorrhiza or VAM (m) with three levels: mycorrhiza 10 g/plant (m1), mycorrhiza 15 g/plant (m2), and mycorrhiza 20 g/plant (m3). The subplot is biochar composition as soil enhancer (b) with three types: biochar husk 50%+25% soil+25% sand (b1), 50% sand+25% soil+25% biochar wood (b2), and wood charcoal biochar 50%+soil 25%+biochar charcoal husk 25% (b3). Each level of the VAM doses factor is combined with biochar. These nine treatment combinations and the levels were repeated thrice, accounting for 27 experimental units. The results showed that the parameters of phosphorus uptake, potassium uptake, and fresh root weight had a positive and significant relationship to the percentage of mycorrhizal infections. The combination treatment of mycorrhiza 20 g/plant and the composition of 50% husk biochar+25% soil+25% sand, 15 g mycorrhizal dose treatment with 50% wood biochar+25% soil+25% biochar rice husk and 20 g/plant are the best treatment as a planting medium.

The objectives of this study are as  follows: first, to investigate the contributing parameters induced land sliding in the Budong-Budong watershed, and second, to construct landslide susceptibility zonation map.  In this study, the analytical hierarchy process (AHP) based on Geographical Information System (GIS) methods was used to produce map of landslide susceptibility. In this study area, more than 50% of total area were classified high (H) to very high (VH)  susceptibility landslide zone.  Mean while, 12% of total area were classified as  moderate (M)  and remaining were classified as  low (L) to very low (VL) susceptibility landslide zone. Almost area of Budong-Budong Wetershed were classified as VH and H susceptibility landslide zone underlying by Talaya (Tmtv), Lamasi (Toml) and Latimojong (Kls) Formation on the steep slope land.

This research was aimed to identify the soil, rock, and tecto-volcanism in their association with landslides intensity in Tondano watershed. The methods were survey method (soil, rock, and geomorphology), joint data processing with stereonet 8, X-ray diffractometers for clay mineral identification, and earthquake data processing with GIS 10.2 Software. The magnitude of earthquake was 4-5.4 mb that resulted from tecto-volcanism activity. The earthquake caused the instability of soil and rock, especially in fault zones. The rock has been strong deformed with the highly developed intensity of fractures (advanced stage). Soil dominated by Kaolinite and vermiculite minerals causes the instability conditions when it is saturated, while the nature of the bedrock with massive open fracture pattern causes the shear strength of the rocks decreases and on the contrary, the shear stress increases. Rainfall intensity is 73-145 mm/day that becomes a major factor of increased soil mass and burdening factor of the unstable rock. Slope is a factor that supports the intensity of mass movements of rock and soil in the form of shallow landslides.