DYNAMIC SOIL PROPERTIES AFFECT THE ACIDITY OF ARTIFICIAL WETLANDS: A CASE STUDY IN THUNG YIEW PAK PHLI OF NAKHON NAYOK PROVINCE, THAILAND

Abstract

This study examined the soil elements and properties of an area becoming an artificial wetland and compared them with those of an agricultural area. The study site is an artificial wetland in Nakhon Nayok Province, Thailand. Its soil properties and element content were compared with a nearby agricultural area using a one-way analysis of variance (ANOVA). The results of the study found this artificial wetland to be within the soil acidity zone of central Thailand, with an average soil pH above 3.99 ± 0.49 and a topsoil organic matter average of 17090 ± 2685mg kg-1, with aluminium (Al) and iron (Fe) as the major soil minerals. Compared to the agricultural area, the soil properties of the artificial wetland had slightly lower topsoil pH but significantly lower pH in the soil layer 100 cm deep in the agricultural area, and the EC in the artificial wetland was higher than in the agricultural area. However, there are three distinct patterns in the elemental composition of the artificial wetland: (1) a lower-quantity soil surface that improves with depth, (2) a high-quantity of topsoil that worsens with depth, and (3) highly variable soil quality below 50–100 cm. In the soil, the organic carbon in artificial wetlands has a ratio of 1:0.17:0.51 to reference area 1 and reference area 2, indicating that wetlands can store carbon in the soil. The element content of the topsoil and 50 cm soil layer is potentially influenced by land use and beneficial microbial activity, and the soil 100–150 cm layer has an element quantity shared with its parent soil. In this study, we sought to understand the physics and chemical composition of soil in an area transitioning to an artificial wetland over approximately 30 years.