Influence of agronomic management on pH and soil organic carbon in oil palm plantations in Indonesia

January 6, 2015. Penang, Malaysia – A study of soil properties in six oil palm plantations in Kalimantan and Sumatra suggests positive implications for soil indicators from management practices supporting yield intensification.

A comparative study of soil properties was conducted in these plantations which implemented best management practices (BMP) for yield intensification as advocated by the International Plant Nutrition Institute’s Southeast Asia Program (IPNI SEAP).

It was found that soil properties did not differ significantly between the BMP and estate reference blocks (REF) after the four years of the trial. This was unexpected, especially as the BMP blocks yielded more than the REF blocks.

Soil analysis was not a useful indicator of oil palm yield, but soil pH and soil carbon content (SOC) increased in both the BMP and the REF treatments during the four years of the experiment. The increase in median pH varied between 0.3–0.45 units in both the BMP and REF blocks. These differences were greater under the frond stacks than under the weeded circle.

SOC percentage increased by about the same amount in the 20-40 cm depth as in the surface soil, with a range 0.03–0.48%. If we ignore the lowest figure, the range is 0.25–0.48%. At a bulk density of 1.4 g/cm³ common in plantation soils, the increase in SOC is 14-26 t/ha over the four years of the experiment (to 40 cm depth), a considerable potential to contribute as potential sinks for atmospheric CO₂. Increases were greater under the frond stacks than in the weeded circles around each palm.

This contrasts with the observation of increasing soil acidification and decreased carbon stocks under oil palm plantations reported elsewhere. The results show that with reasonable management, soil quality under oil palm can improve.

Further research on the mechanisms by which BMPs can improve soil quality, and monitoring over longer periods of time is recommended to provide a clearer picture of the potential ‘co-benefits’ that can be obtained with adoption of BMPs designed to increase oil palm yield.

For more information, see the published paper here.


About IPNI
The International Plant Nutrition Institute (IPNI) is a not-for-profit, science-based organization dedicated to the responsible management of plant nutrition for the benefit of people. Through cooperation and partnerships with respected institutions around the world, IPNI adds its strength to agronomic research, education, demonstrations, training, and other endeavors. Best management practices for nutrient stewardship encourage the concept of 4Rs - applying the right nutrient source, at the right rate, at the right time, and in the right place. To learn more about IPNI, please visit: www.ipni.net

Contact
Dr. Thomas Oberthür, IPNI Director of Southeast Asia Program
Email: toberthur@ipni.net