Effects of Organic Materials and Rainfall Intensity on the Productivity of Oil Palm Grown under Sandy Soil Condition

Oil palm plantations in Indonesia are cultivated on various types of land, ranging from very suitable  to unsuitable  types. This cultivation method is increasingly vulnerable to drought caused by climate change. Climate change due to global warming negatively affects the management of oil palm plantations in the long term.  The upper-temperature limit for efficient photosynthesis in oil palm leaves is >38 °C. The increase in temperature (2°C above the optimum) and rainfall by 10% is projected to cause a yield decline of up to 30%.  The water shortage is also a major limiting factor for palm oil production. Such vulnerability is predicted to worsen, and thus its negative effects should be explored. The purpose of this study is to reveal the role of organic matter applied as empty bunches (EFB) and the management of Nephrolepis bisserata vegetation in reducing the adverse effects of rainfall on palm oil production on sandy soils. The survey method and observations were carried out for over 3 years on plants aged 14-16 years on blocks. Empty fruit bunches (EFB) of 40 tons/ha/year was applied to each block, and Nephrolepis biserrata  was used as ground cover which planted in path. The parameters observed included the number and average weight of fresh fruit bunches (FFB). The relationship between fluctuations in the conditions of monthly rainfall intensity on oil palm production was determined through regression analysis.  Rainfall strongly influenced the number of FFB, whereas the average weight of FFB remained relatively constant. The application of EFB and management of Nephrolepis biserrata   vegetation facilitates the reduction of drought impacts and increase in oil palm production (15%) as shown in bunch weight and bunch number.  EFB and Nephrolepis biserrata  vegetation can increase soil organic matter content and improve soil water holding capacity.