Liming and soil acidity management in tropical peatlands under oil palm: a review

In Southeast Asia, vast tracts of tropical peatland have been converted to agricultural land, primarily for the establishment of oil palm plantations, due to anticipated significant economic benefits for the nations involved. Peat soils, on the other hand, have been considered a challenge for agricultural activities. One of the primary agronomic challenges in crop production on peat soil is its high acidity (pH 3.3–3.5) and low fertility. To address these constraints, liming has become a common agricultural practice to adjust soil pH. However, due to the substantial buffer capacity in peat soil, determining optimal lime rates for maximum productivity and cost-effectiveness is relatively challenging. Liming can enhance the physical, chemical, and biological characteristics of soil by reducing its acidity and mobilizing certain elements through direct and indirect mechanisms. Nevertheless, the effectiveness of lime in improving crop productivity is affected by various factors, including initial soil pH, peat heterogeneity, crop species, lime material type, and application method. Plants require a large amount of macronutrients to grow and thrive. In soil with high acidity, most macronutrients are less available to plants. Hence, this review aims to examine how liming helps manage soil acidity and improve soil conditions for oil palm growth on tropical peat soils.