Land use and soil quality in peri-urban farms in Southern Brazil

Small family farms constitute a major part of land use in the surrounding regions of Brazilian cities, as these farms not only contribute to the food supply, but also help conserve rural landscapes and improve environmental services. This study evaluated agricultural impacts on soil quality in seven family farms in Porto Alegre municipality, Rio Grande do Sul state, RS. Selected production units (PUs) were managed as conventional or organic farms, producing horticultural crops, fruits and pastures, besides native forests. Soil samples were collected from representative areas for five use and management types, under disturbed and undisturbed conditions, at 0–20 cm depth. Physical and chemical attributes were analyzed, comparing the effects of types of land use. Data analysis showed that more affected attributes were soil density, macro and microporosity, phosphorus content, pH and electrical conductivity. Macroporosity, phosphorus, zinc and cooper contents are the greater threats to soil quality. Horticulture, under both agroecological and conventional production systems caused major changes compared to natural conditions.