LCA and nutritional assessment of southern Benin market vegetable gardening across the production continuum

Abstract

Abstract Purpose The goal of this work is to analyse the environmental impacts across the productive continuum of market gardening in southern Benin, to determine whether significant differences exist amongst the types of production, and to highlight their hotpots suitable to improvement. Moreover, the relative nutritional quality of products from different production system types were compared to determine whether there were differences and to assess them in relation to the associated environmental impacts. Methods LCA and laboratory analyses were performed on a representative sample of systems and products (carrot, cucumber, tomato, lettuce, watermelon). The resulting scores (single scores for LCA and Nutrient Rich Food scores for nutritional quality) were statistically treated to identify the representativeness of their differences across production sites and production types (featuring distinctive production strategies: Conventional — synthetic fertilisers and pesticides, Organic — organic fertilisers and pesticides and “Lean” — limited inputs). Results and discussion Statistically significant differences across environmental scores were found amongst production sites (for carrot, lettuce and all crops) and types (for carrot and all crops). For tomato, produced on all sites, under all production types, the natural and management-driven variability is large enough that no significant differences were found. Impacts are dominated by direct emissions from (over-)fertilisation and by fuel consumption for water pumping. Despite the absence of significant differences amongst production system types regarding the contents of both β-carotene and polyphenols, the nutritional indices suggest at least marginal differences across types regarding the overall nutritional value of carrot and tomato across types. Based on the limited data available, it cannot be stated that such differences are statistically significant. For carrot, there seems to be a correlation between nutritional quality and environmental impacts, with higher nutritional scores associated with lower environmental impacts. For tomato, it does not seem to exist a correlation. Conclusions Significant differences in environmental scores exist amongst the types of production, with the larger impact associated with organic production, whilst that no statistically significant differences on nutritional quality can be demonstrated across types. Overall improvement of these systems would be achieved by less energy-intensive irrigation, organic waste processing platforms to reduce volatilisation losses, knowledge on the fertilising value of organic waste, and agricultural extension services or technical guides on good agricultural practices to reduce over-fertilisation and other negative environmental impacts.