Economic and Environmental Effects of Replacing Inorganic Fertilizers with Organic Fertilizers in Three Rainfed Crops in a Semi-Arid Area

Abstract

This study evaluates the economic and environmental effects of replacing inorganic fertilization with organic fertilization (manure and compost) in three characteristic crops of the rainfed land of southeastern Spain: almond, olive, and barley. To do this, the conventional cultivation model of the three production systems was established and analyzed through the LCC (Life Cycle Costing) and LCA (Life Cycle Assessment) methodologies. Next, a sensitivity analysis was performed to see the effects of the substitution. In the three conventional systems, inorganic fertilizers represent at least 11% of the total costs. At the same time, they are the element with the greatest global contribution to environmental impacts (between 60 and 88%). Through the sensitivity analysis, it was shown that tillage practices that involve the addition of manure or compost not only reduce costs for the three crops (with a maximum reduction of EUR 88/ha in the case of olive trees with compost application), but also most of the impact categories evaluated. In terms of global warming, the reduction varies from 2–9% depending on the crop and the organic fertilizer used. And if we take into account that the production of inorganic fertilizers is avoided, the results of this category decrease between 28% and 48%.