The use of oil palm empty fruit bunches as a soil amendmentto improve growth and yield of crops. A meta-analysis

Oil palm plantations worldwide generate vast amounts of empty fruit bunches (EFB), often disposed of as waste and left to undergo natural decomposition or incinerated, contributing to greenhouse gas emissions. However, EFB could be used as soil conditioner to improve soil properties and increase crop yields. We conducted a meta-analysis to synthesize evidence of the effect of soil amendment by different forms of EFB on crop growth and yield and how other factors moderate performance. The meta-analysis included 19 studies on the growth and yield of crops grown on EFB-amended and unamended soils. Applying EFB as mulch, biochar, or compost to soil led to a 49.2% increase in crop growth and yield compared to unamended soils. When EFB were co-applied with a second material such as mineral fertilizers, crop growth and yield was increased by 16.4% compared to unamended soils. The growth and yield advantages were affected by the location of the experiment, soil texture, or the form of EFB applied. Compared to unamended soils, crops grown on soils amended with pyrolyzed EFB, raw EFB, composted, and ash EFB recorded growth and yield increase by ~78.4%, 33.8%, 30.9%, and 21.0%, respectively. Overall, amending soil with EFB is likely to increase crop yield. Still, the benefits must be clarified by a benefit-cost analysis based on the ratio of yield advantages from its usage to the cost of accessing or using the product by farmers.