Monitoring of pH level for maximizing oil palm ffb yields

Abstract

Abstract Depending on the location of estates and types of soils, monitoring of pH changes is an integral part of soil-water management for realizing sustainable Fresh Fruit Bunches (FFB) yields. In Sumber Tani Agung Resources Tbk, fluctuations in pH levels in field blocks as well as nearby drains were monitored since 2019. The usage of portable units of pH meters made it possible for planters to record and monitor the on-site changes in pH. Monitoring of pH was done on two types of soils namely peat (three estates in North Sumatra) and acid sulfate soils (two estates in South Sumatra). Piezometer was established in each block in all five estates and pH reading was taken biweekly, including at nearby watergates for comparison. Lower pH values ranging from 3.5 to 3.7 were observed at piezometers and water gates on blocks established on acid sulfate soils as compared to pH values recorded in peat areas where slightly higher pH values were registered (4.3 to 5.6). The presence of pyrite contributed to a lower range of pH values on acid sulfate soils. Keeping water level at 40-70 cm on peat and at 45-60 cm for acid sulfate soils would have an impact on the improvement of soil physical chemistry and biology properties, besides creating aerobic conditions for roots of the cultivated oil palms. Organic fertilizer such as bunch ash was applied in the 2020-2021 period which also resulted in an increment in pH values. Generally, there were improvements in oil palm growth as well as palm yield performance in areas with higher pH values (>4.50).