The carbon storage potential of selected ultramafic soils in Puerto Princesa City and Bataraza, Palawan, Philippines

Abstract

The primary environmental challenge of this 21st century is climate change, induced by carbon dioxide, with limited research focusing on the soil carbon-trapping potential of forest formations such as ultramafic. However, understanding the physicochemical properties of soil is essential to determine the carbon storage potential of soil organic matter, which is investigated in the mineral-rich ecosystem in Palawan Island. Ultramafic forests from Brgy. Rio Tuba, BatarazaW and Sitio Magarwak, Brgy. Sta. Lourdes, Puerto Princesa City, Philippines, was considered for the present study. Pearson and Kruskal-Wallis tests were used to establish a hierarchy of soil physicochemical parameters, such as carbon, pH, texture, particle and bulk density, porosity, and organic matter (OM) about carbon storage potentials. Most ultramafic soils were sandy loam or sandy clay loam with low bulk BD and clayey, which stores more carbon than sandy soils. Among the soil properties, soil texture, particularly clayey soil, has more influence (p = 1.46E⁻¹³) in the soil organic carbon (SOC) pool than soil pH (p = 0.59), soil porosity (0.39), bulk density (0.37), and particle density (0.32). SOC was inversely proportional to BD, with soil porosity directly affected by soil depth. SOC and organic matter decreased at a depth with higher carbon sequestration at the rhizosphere layer, ranging from 4–7 % in the topsoil to 3–5% in the subsoil. The ultramafic area of Puerto Princesa City stored higher organic carbon (99.05 tons ha–1) than that of Bataraza (85.68 tons ha–1).