Effect of Burkholderia cepacia and SP36 on available phosphate and potato production on Andisol impacted by Mount Sinabung Eruption, North Sumatera, Indonesia

Abstract: Since 2013, Mount Sinabung has erupted and changed soil properties including microorganisms in the soil and affected the production of potatoes in Karo highland in Indonesia. In vitro screening of bacteria from surrounding horticulture land, their ability to dissolve phosphate showed that Burkholderia cepacia was the best bacteria. The aim of this study was to examine the capability of B. cepacia and P fertilizer on Andisol in improving soil P- available and production of potato (Solanum tuberosum L). The research design used was factorial randomized block with two factors. Factor I was the volume of B. cepacia inoculum, consist of 4 treatments; without B. cepacia, 10, 20 and 30 mL B. cepacia inoculum. Factor II was the dosage of SP36, consist of 3 treatments: 50, 75 and 100% from recommended dosage (9.75 g, 6.5 g and 13 g SP36/plant, respectively). The control was potato plant without applying B. cepacia but adding 7.8 g Urea, 10 g KCl and 13 g SP36 (100% suggested P fertilizer) which was applied twice with the same dosage. The results showed that application of B. cepacia application and P fertilizer dosage increased shoot dry weight 50.07-113.73%, soil P available 5.04-35.42%, P-uptake 34.47-163.28% and tuber yield 12.57-50.66% compared with control. The best treatment in increasing potato tuber yield was 20 mL B. cepacia/plant and 9.75 g SP36/plant.