Effect of Pyritic Material on Soil Chemical Properties and Oil Palm (E. guineensis) Production

Abstract

Development of oil palm plantation areas in Indonesia has significantly increased every years. This makes the development leads to marginal lands, like the lands acid sulfate soil which has sulfidic material. The expansion of the plantation into the marginal lands, is not an expected alternative, but the suitable lands were limited. Oxidation of pyritic material in aerobic condition will produce sulfuric acid and mineral jarosit with extreme acidity that can prohibit plant growth. The conditions is obtained due to land reclaimation through establishment of drainage facilities. On the other hand, large amounts of plant nutrients washed out from the lands. The leaching are more conducive in high acidity drainage water. Ultimately this processes are reducing soil fertility with low soil pH as well. The study aims to determine the effect of different depths of pyritic material and pyrite oxidation on soil chemical properties and oil palm production. Location of soil sampling and observations conducted in the oil palm plantation Business Unit Bentayan and Betung Krawo, PT Perkebunan Nusantara VII (Persero), South Sumatra. Analysis of soil samples carried out at the Laboratory of Department of Soil Science and Land Resources, Faculty of Agriculture, Bogor Agricultural University. Observations focused on the depth pyritic material at <30 cm, 30-60 cm, and > 60 cm, and not containing pyritic material. Special observation conducted on soil chemical properties at the soil with and without oxidation. The results show that the content of pyrite at depths <30 cm have a significant effect on increasing soil acidity and exchangeable aluminum content (Al-dd), and reduced levels of N-total nutrients, potassium (K) and production of fresh tube fruits. Oxidation pyrite also gives a tendency of decreased levels of available nutrients phosphorus (P), calcium (Ca), magnesium (Mg), and base saturation. Pyritic lands which have undergone an oxidation process tended to decrease fertility.