Carbon emissions and economic assessment of farm operations under different tillage practices in organic rainfed almond orchards in semiarid Mediterranean conditions

Abstract

Sustainable land management practices, such as reduced tillage or crop diversification, are potentially efficient measures to fight against soil degradation and desertification. The decision to approve these practices must be justified by both integrated environmental and economic assessment studies. In this work, we analysed the carbon emissions associated to farm operations and economic profitability for two organic rainfed almond (Prunus dulcis Mill.) farms under semiarid conditions. In the analysis, we considered the following soil management strategies: conventional tillage (CT); reduced tillage (RT); reduced tillage plus green manure (RTG); and no tillage (NT). A cradle-to-farm gate life cycle assessment (LCA) was applied based on long-term data from two farms. The results obtained showed that the NT strategy provided, as expected, the lowest greenhouse gas (GHG) emissions but that its yield was also the lowest, which negatively affects its economic viability even with the consideration of subsidies. The RT strategy reduced GHG emissions and improved the ratio of profit/GHG emissions, whilst the RTG strategy increased GHG emissions and reduced the ratio of profit/GHG emissions as a consequence of using seeds. In conclusion, it has been demonstrated that some level of reduced tillage leads to environmental and economic benefits with respect to conventional tillage in organic rainfed almond orchards under semiarid conditions.