Effects of Pinus radiata afforestation on soil carbon sequestration and soil quality in maritime dunes

ARES, A; AMIOTTI N. M; ZALBA, P.; ROSSI, JM.

Congreso; XXIII Internacional Union of Forest Research Organizations; 2010

Afforestation of grasslands can increase carbon sequestration and provide additional environmental benefi ts. Pine plantations, however, can deplete soil organic carbon and have other detrimental effects on soils. We examined soil characteristics under a 45-yr old Pinus radiata stand and adjacent grassland on maritime dunes in temperate Argentina. Soil under the pine plantation had greater soil carbon (+ 93%), total nitrogen (+ 55%), and available phosphorus (+ 100%) concentrations than under grassland. Carbon was stored both in the organic and mineral horizons at an accretion rate of 0.64 Mg/ha yr. At 0- to 25-cm depth, soil carbon amounted to 61 Mg/ha under pine and 27 Mg/ha under grassland. Soil carbon accumulated more in dune slopes (35 Mg/ha) than in ridges (29 Mg/ha) and bottoms (12 Mg/ha). Compared with the grassland, soil acidity, cation exchange capacity, base losses (potassium > calcium = magnesium), and C/N ratio increased under pine topsoil. Spatial heterogeneity in soil characteristics was greater under pine than in grassland. Such variability was non-systematic and did not validate the “single-tree infl uence circle” concept. Afforestation contributed to develop carbon sinks in soil, forest fl oor, and tree biomass in maritime dunes with ustic climate regime. had greater soil carbon (+ 93%), total nitrogen (+ 55%), and available phosphorus (+ 100%) concentrations than under grassland. Carbon was stored both in the organic and mineral horizons at an accretion rate of 0.64 Mg/ha yr. At 0- to 25-cm depth, soil carbon amounted to 61 Mg/ha under pine and 27 Mg/ha under grassland. Soil carbon accumulated more in dune slopes (35 Mg/ha) than in ridges (29 Mg/ha) and bottoms (12 Mg/ha). Compared with the grassland, soil acidity, cation exchange capacity, base losses (potassium > calcium = magnesium), and C/N ratio increased under pine topsoil. Spatial heterogeneity in soil characteristics was greater under pine than in grassland. Such variability was non-systematic and did not validate the “single-tree infl uence circle” concept. Afforestation contributed to develop carbon sinks in soil, forest fl oor, and tree biomass in maritime dunes with ustic climate regime. had greater soil carbon (+ 93%), total nitrogen (+ 55%), and available phosphorus (+ 100%) concentrations than under grassland. Carbon was stored both in the organic and mineral horizons at an accretion rate of 0.64 Mg/ha yr. At 0- to 25-cm depth, soil carbon amounted to 61 Mg/ha under pine and 27 Mg/ha under grassland. Soil carbon accumulated more in dune slopes (35 Mg/ha) than in ridges (29 Mg/ha) and bottoms (12 Mg/ha). Compared with the grassland, soil acidity, cation exchange capacity, base losses (potassium > calcium = magnesium), and C/N ratio increased under pine topsoil. Spatial heterogeneity in soil characteristics was greater under pine than in grassland. Such variability was non-systematic and did not validate the “single-tree infl uence circle” concept. Afforestation contributed to develop carbon sinks in soil, forest fl oor, and tree biomass in maritime dunes with ustic climate regime. Pinus radiata stand and adjacent grassland on maritime dunes in temperate Argentina. Soil under the pine plantation had greater soil carbon (+ 93%), total nitrogen (+ 55%), and available phosphorus (+ 100%) concentrations than under grassland. Carbon was stored both in the organic and mineral horizons at an accretion rate of 0.64 Mg/ha yr. At 0- to 25-cm depth, soil carbon amounted to 61 Mg/ha under pine and 27 Mg/ha under grassland. Soil carbon accumulated more in dune slopes (35 Mg/ha) than in ridges (29 Mg/ha) and bottoms (12 Mg/ha). Compared with the grassland, soil acidity, cation exchange capacity, base losses (potassium > calcium = magnesium), and C/N ratio increased under pine topsoil. Spatial heterogeneity in soil characteristics was greater under pine than in grassland. Such variability was non-systematic and did not validate the “single-tree infl uence circle” concept. Afforestation contributed to develop carbon sinks in soil, forest fl oor, and tree biomass in maritime dunes with ustic climate regime.