Driving Mechanism Controlling Cultivated Tropical Peat Physicochemical Characteristics and Stoichiometry: Case Study of a Microtopographical Sequence

Contrasting to the large body of knowledge documenting peatland characteristics and their trends across major rivers, limited study was found in studying peat physicochemical and stoichiometry variability at the drained and cultivated site across microtopographical sequence. This study aimed to investigate peat physicochemical properties and stoichiometry in an old oil palm plantation/OPP in North Sumatra Province, Indonesia, across a 3.1 km of a topo-hydrosequence transect perpendicular to the Leidong River and raised hummock. 20 peat cores (0-50 and 50-100 cm depth) from 10 sampling points were collected to determine their physicochemical properties and stoichiometry and analyze the driving mechanisms controlling them. This current study suggested that the long-term drainage and cultivation practices may partially alter the trends and patterns of peat’s physicochemical properties. It was indicated by diverse trends, in which several peat properties behave oppositely against their natural patterns. The soil’s chemical characteristics and stoichiometry throughout 0-100 cm depth were considered homogeneous, which exhibited oppositely with peat physical parameters. The prominent properties and stoichiometry mainly controlled peat variances were bulk density, pH, total N, available P, C:N, and N:K. Flooding experience and distance from the river were the driving mechanisms controlling peat properties and stoichiometry at the study site. This study’s results demonstrated peat physicochemical characteristics and stoichiometry trends that were observed at microtopographical features with a relatively small tributary may resemble those studies representing the extensive landscapes