Net CO2 storage in mediterranean olive and peach orchards

Long-Term Effects of Residue Management on Soil Fertility in Mediterranean Olive Grove: Simulating Carbon Sequestration with RothC Model

“…Many authors have also found a rise in SOC values in agricultural soils within at least the uppermost 10 cm in depth, after using conservation practices (Angers et al, 1997;Hernanz et al, 2002;Jarecki & Lal, 2003). In olive orchards, some authors as Hernández et al (2005), Sofo et al (2005), Castro et al (2008) and Gómez et al (2009), have reported increases in the SOC and N content after applying plant residues. Our values were higher than those reported by these authors because, together with the shredded pruning debris, a major quantity of residues composed of soil and plant debris were brought from the olive-cleaning processes, reaching a biomass accumulation greater than that indicated by these authors.…”

“…Romanyà et al (2000) registered similar results for a vineyard in the Mediterranean area, with an annual carbon input of 1.4 Mg C ha -1 yr -1 . The only estimates of carbon input for olive groves were reported by Sofo et al (2005), who registered an annual input as senescent leaves of 0.4 Mg C ha -1 yr -1 but did not account for other inputs such as root turnover and rhizodeposition. In our work, the SOC content modelled for the VRcc soil ( Figure 3) was higher than that predicted for the CLcr after eight years of mulching.…”

“…This showed rapid migration of carbon and thus a soil that is not close to equilibrium. During the first years of olive-tree establishment, CO 2 is distributed preferentially in the permanent structures and the root system, but in mature olives trees, fixed CO 2 is located to a greater extent in the leaves and fruit, and consequently also in the pruning debris (Sofo et al, 2005). Thus pruning debris is an important carbon reservoir that can be returned to the soil rather than the atmosphere in the form of CO 2 (Figure 3).…”

“…The impact of different soil-management systems on soil properties have been studied for olive orchards (e.g. Hernández et al, 2005;Soria et al, 2005;Castro et al, 2008;Gómez et al, 2009) but only a few works have evaluated the effect of shredded olive-pruning debris (Ordóñez et al, 2001, Sofo et al, 2005Rodríguez-Lizana et al, 2008). Recently, agricultural soils have been identified as the major carbon pool in the context of its global cycle.…”

Improving the accounting of field emissions in the carbon footprint of agricultural products: a comparison of default IPCC methods with readily available medium-effort modeling approaches

“…The amounts of C added to the soil during the mature stage of the orchards (i.e., as crop residues and organic fertilizers) were derived from direct field measurements: figures regarding the dry matter of senescent leaves, pruning residues, thinned fruit, and grass cover were retrieved from field sampling performed at site 3b from 2004 to 2010 (from 8th to 14th year after establishment) and at site 3a in 2013-2014 (8th and 9th year after establishment), assuming a mean C content of 0.45 t C per ton of dry matter, and a grass cover below-ground contribution of 20 % (Celano et al 2003). The C input during the young stage of the orchard (senescent leaves and pruning material) was retrieved from an experiment performed in a peach orchard located in the same area, with same rootstock, same training method, comparable management regime, and adapting data to the different tree density per hectare (Sofo et al 2005). The C input from root turnover was calculated as 30 % of the trees' above-ground biomass turnover (senescent leaves, pruning material, and fruit yield) for the first 3 years and as 25 % for all other years (Buwalda 1993).…”