ChileanJAR

The use of soils affects their properties and edaphic characteristics such as nutrient availability, depending upon soil management practices. The largest impacts are due to native forest destruction and tillage in steep slopes which accelerate soil erosion, therefore resulting in the lost of the most fertile horizons. In order to evaluate the impact of three systems of soil use upon sorne soil properties, samples from the surface and subsurface horizons were obtained from soil pits, allowing the proper definition of the two more superficial soil horizons to be achieved. Total carbon (Ct), total nitrogen (Nt) and inorganic nitrogen (Ni) values were determined as well as the available fractions, or available indexes ofphosphorus, potassium, magnesium, sulphur and boron. The Ct content was not affected by the soil use, which reflects its stability in the sampled soils. C/N ratios were very high in the natural pasture and exotic forests (BE) soils with values of 17.7 and 20.3, respectively. Litter had a Ct content of 57.1% in the native forest (BN). The largest impact on Nt occurred in the BE soil. The Ni contents were medium to high despite the high rainfall ofthe zone. The BE soil presented an accumulation ofK and Mg in the surface horizon which is Iikely due to a litter effect. Sulphur and boron contents were adequate.