Variability of Soil Types in Wetland Meadows in the South of the Chilean Patagonia

Abstract

The wetland meadows and pastures (vegas) of the agricultural zone of the Magallanes Region and the Chilean Patagonia are productive and intensively exploited ecosystems. However, there is scarce data about the typology and the physical and chemical properties of the soils that determine the agricultural potential of vegas sites. Sampling of the main horizons of 47 soil profiles was conducted throughout the area. The profiles were described in the field and consequently classified according to the soil typology system of the WRB (IUSS Working Group WRB, 2006). Analyses of bulk and particle densities, capillary water capacity, pH (H2O), pH (CaCl2), texture, organic material, C:N ratio, electrical conductivity, effective cation exchange capacity, N, P, Ca-Mg-K-Na, exchangeable Al, extractable Al, sulfur SO42-, B, and micronutrients (Cu-Zn-Mn-Fe) were carried out. The most frequently recorded groups of soil types in the studied vegas were Histosols - peat soils (20 profiles), and Fluvisols (19). Gleysols (3), Vertisols (1), Regosols (3), Solonchaks (1) and Solonetzs (1) were detected with much less frequency. There is also considerable variability in soil properties among and within the groups of soil types. The principal differences between the Histosols and the Fluvisols are the content of organic matter (often peat), pH level (related to the absence/presence of carbonates) and associated soil properties. Fluvisols are more susceptible to salinization under conditions of aridity, whereas the main threat to Histosols is artificial drainage.