Linking Soil Organic Carbon Stocks to Land-use Types in a Mediterranean Agroforestry Landscape

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 In agroforestry landscapes, land use, and the associated management practices exert strong impacts upon soil organic carbon stocks. Data on the soil organic carbon were collected for different land-use types within a small watershed, El Salado, located in Lanjarón (SE Spain). Eight land-use types namely: farmland planted in olive, almond, and cereals; forest with Pinus halepensis Mill. and Pinus sylvestris L. stands; shrubland; grassland; as well as abandoned farmland were taken into consideration. Of the land-use types investigated, forest, shrubland, as well as grassland exhibited the highest average soil organic C stocks (100-63 Mg ha-1) in contrast with the abandoned farmland (28 Mg ha-1), with farmland representing a go-between situation (51-49 Mg ha-1). The environmental factors precipitation, temperature, and elevation significantly influenced (P< 0.01) the soil organic C stock, with the contents tending to be higher in mountain soils with respective intermediate values of 600-800 mm, 10-15ºC, and 1,000-1,500 m asl. Thus, the present approach offers a comparison of C-sequestration patterns as related to the land-use types in a Mediterranean agroforestry landscape, where the main challenge is to integrate the forest trees and the crops within their harmonious interacting combinations.