Absorption of atmospheric CO2 in peach trees and its partitioning in the different plant organs

The concentration of CO2 has increased during the 20th century and it is estimated that if some actions are not taken against this increase, current CO2 concentrations are expected to double before the end of this century. Agricultural techniques play a key role in CO2 emission and fixation. In the present investigation, we examined carbon fluxes in a peach orchard. We hypothesized that correct utilisation of agricultural techniques, and soil management in particular, could increase the absorption of atmospheric CO2 and its storage in the soil, thereby mitigating the environmental damages caused by the greenhouse effect. Trials were carried out in southern Italy (N 40°20', E 16°48') from the first to the fifth year after planting on peach trees (Prunus persica (L.) Batsch, cultivar 'Springcrest') budded on GF677. Trees were trained to transverse Y or delayed vase, at planting densities of 1111 trees/ha-1 and 416 trees/ha-1, respectively. At the end of the vegetative season, values of fixed atmospheric CO2 and CO2 accumulation rates were calculated by measuring the dry matter partitioning in the different plant organs. In the first years after planting, CO2 was mainly allocated to the permanent structures (trunk and roots), while in the mature orchards, fixed CO2 was also distributed in leaves, pruning material and fruits. Green manure increased CO2 fixation to about 11 t ha-1. The results underline the importance of training system, plant density and cultivation techniques in the absorption of atmospheric CO2 and its storage as organic matter in the soil.