Abstract   Geothermal manifestations on Bangka Island are found in the villages of Terak, Pemali, Sungailiat/Pelawan, Dendang, Permis, and Nyelanding. The manifestation of hot water in Terak Village, Central Bangka Regency is in the form of 3 hot springs with a surface temperature of 55ᵒC this research is to be carried focus on the structure of the subsurface rock layers using the geophysical method, namely the gravity method. The data used are topography and Free Air Anomaly. The data processing is in the form of Bouguer Correction and Terrain Correction to obtain the Complete Bouguer Anomaly (CBA) value. Then the CBA value is separated from regional anomalies and residual anomalies using the upward continuation method, as well as 2D modeling interpretation (forward modeling). From the research results, it is known that the subsurface rock structure of the non-volcanic geothermal system in Terak Village in the form of sandstone (2.28 – 2.49 gr/cm3) at a depth of 0 – 1.44 km is estimated as caprock, granite (2.77 – 2.78 gr/cm3) at a depth of 0 – 1.8 km is estimated as reservoir rock, and diorite rock (2.87 – 2.99 gr/ cm3) at a depth of 0 – 2 km is estimated as basement rock.  

This study aims to see the growth and yield of hybrid red chili with various varieties and the dose of NPK Mutiara fertilizer and to see the interaction between hybrid red chili varieties and the dose of NPK Mutiara fertilizer. This study used a factorial randomized block design (RAK) consisting of 2 factors, namely the red chili variety factor (V) which consisted of 3 types: V1 = Kastilo F1, V2 = Laju F1, and V3 = Lado F1. The combination factor of NPK fertilizer (P) consisted of 3 levels: P1 = 19 g/plant, P2 = 23 g/plant, and P3 = 28 g/plant. Parameters observed included flowering age (Days), stem diameter (cm), number of chilies per plant (fruit), chili length (cm), chili diameter (cm), fresh chili weight per plant (gr), and fresh fruit weight. per plot (gr). The results showed that hybrid red chili varieties had a significant effect on the parameters of the number of chilies per plant, the weight of fresh chilies per plant, and the weight of fresh chilies per plot. The best results were obtained in the V2 treatment (F1 Laju). The dose of NPK Mutiara had a significant effect on the parameters of flowering age and chili length. The best results were obtained in the P3 treatment (28 g/plant). The interaction of hybrid red chili varieties with NPK Mutiara fertilizer had a significant effect on chili length parameters and the number of chili peppers per plant. However, it had no significant effect on flowering age, stem diameter, chili diameter, fresh chili weight per plant, and fresh chili weight per plot. The best interaction was found in the V2P3 treatment (F1 rate + 28 g/plant).