Evaluation of carbon stock variation in Northern Italian soils over the last 70 years

Carbon (C) sequestration in soils is gaining increasing acceptance as a means of reducing net carbon dioxide (CO₂) emissions to the atmosphere. Numerous studies on the global carbon budget suggest that terrestrial ecosystems in the mid-latitudes of the Northern Hemisphere act as a large carbon sink of atmospheric CO₂. However, most of the soils of North America, Australia, New Zealand, South Africa and Eastern Europe lost a great part of their organic carbon pool on conversion from natural to agricultural ecosystems during the explosion of pioneer agriculture, and in Western Europe the adoption of modern agriculture after the Second World War led to a drastic reduction in soil organic carbon content. The depletion of organic matter is often indicated as one of the main effects on soil, and the storage of organic carbon in the soil is a means of improve the quality of soils and mitigating the effects of greenhouse gas emission. The soil organic carbon in an area of Northern Italy over the last 70 years has been assessed In this study. The variation of top soil organic carbon (SOC) ranged from −60.3 to +6.7%; the average reduction of SOC, caused by agriculture intensification, was 39.3%. This process was not uniform, but related to trends in land use and agriculture change. For the area studied (1,394 km²) there was an estimated release of 5 Tg CO₂-C to the atmosphere from the upper 30 cm of soil in the period 1935–1990.