Local bio-activators increased rice yield in paddy soils of East Kalimantan, Indonesia.

Low soil fertility of acid paddy soils in East Kalimantan becomes the primary constraint in boosting rice yield. Generally, integrated soil management by applying organic matter, lime, humic acids, biofertilizer, and zeolite improves the soil's physical, chemical, and biological quality. To promote rice productivity in acid paddy fields, we tested the effectiveness of local bio-activators in promoting rice growth and flowering. The experiment was carried out from July to November 2020 in Embalut Village, Kutai Kertanegara Regency, East Kalimantan (Indonesia). We used a split-plot design using two factors and three replications, using Cibogo as a standard variety. The first factor was the application of local bio-activators by using four levels (A-0: control, A-1: 100mL/L, A-2: 150mL/L, A-3: 200mL/L). The second factor was spraying frequency during ten days intervals using four levels (F-0: control, F-1: twice, F-2: four times, dan F-3: six times). The results showed that pyrite was on the soil after four days of application on the soil surface. In addition, rice sprayed by local bio-activators was more resistant to leaf blasts. The application of local bio-activators increased soil quality and rice yield. The highest yield was from four-time spraying (128.50g, equivalent to 8.03t unmilled rice per ha) and a dose of 10 L/ha (122.22 g, equivalent to 7.64 t unmilled rice per ha). Bio-activator is prospective material for improving rice production. [ABSTRACT FROM AUTHOR]