CONTEXT: To design policies for sustainable irrigation planning, public decision-makers need knowledge about the potential environmental impacts of irrigated farming systems. In a previous paper, we proposed to couple Life Cycle Assessment (LCA) and Agrarian System Diagnosis (ASD) to build the Life Cycle Inventory (LCI) of a farming region in a context of data scarcity and farming system diversity. This method was applied to the semi-arid irrigated plain of Kairouan (Tunisia). OBJECTIVES: The aim of the present paper is to demonstrate how this new ASD-based LCA method is used to conduct the impact assessment of this farming region, under current conditions and for two prospective scenarios. METHODS: Two functional units (FU) were used: the area and the gross product generated. Life Cycle Impact Assessment (LCIA) was conducted based on a multilevel process, by converting LCI data collected for each cropping/ livestock system into LCIA outputs, which were then consolidated at the farming system (FS) and at the regional scales. Two model scenarios were built: the agrarian scenario (shift from family to corporate farming) and the hydrological scenario (water table drawdown). RESULTS: Environmental hotspots were identified at each scale: the most impactful FS was the « mixed family farming » (intermediate access to water), because of its large share of land territory (45%). In this FS, the most harmful cropping system was input-intensive olive groves intercropped with a melon-pepper/ cereal/ tomato rotation, in which most impacts (35%) were attributable to the input-intensive “melon” crop, and more particularly to " manufacture and transport of fertilizer", including farmyard manure. Globally, the most harmful processes were water depletion and fertilizer use (fertilizer manufacturing and transportation). This downscaling is very useful to inform public policies on the most harmful productions. The scenarios resulted in impact increases of 11%, 2%, 9% and 23%, 27% and 40%, in human, ecosystem and resource endpoints for the agrarian and hydrological scenarios respectively. SIGNIFICANCE: Our method has three main strengths: i) inter-farms synergies are accounted for in the LCIA, which is essential to promote circularity; ii) the origins of environmental hotspots can be investigated and later mitigated by future policies; iii) ASD helps to design scenarios by identifying current trends and thresholds (resources, pollution and workforce) that cannot be overcome on the territory. Lastly, to build policies for sustainable irrigated agriculture, we encourage the use of this method in participatory approaches.

CONTEXT: To design policies for sustainable irrigation planning, public decision-makers need knowledge about the potential environmental impacts of irrigated farming systems. In a previous paper, we proposed to couple Life Cycle Assessment (LCA) and Agrarian System Diagnosis (ASD) to build the Life Cycle Inventory (LCI) of a farming region in a context of data scarcity and farming system diversity. This method was applied to the semi-arid irrigated plain of Kairouan (Tunisia).OBJECTIVES: The aim of the present paper is to demonstrate how this new ASD-based LCA method is used to conduct the impact assessment of this farming region, under current conditions and for two prospective scenarios.METHODS: Two functional units (FU) were used: the area and the gross product generated. Life Cycle Impact Assessment (LCIA) was conducted based on a multilevel process, by converting LCI data collected for each cropping/ livestock system into LCIA outputs, which were then consolidated at the farming system (FS) and at the regional scales. Two scenarios, based on observed trends, were assessed: the "agrarian" scenario (driven by a shift from family to corporate farming) and the "hydrological" scenario (driven by a water table drawdown).RESULTS: Environmental hotspots were identified at each scale: the most impactful FS was the "mixed family farming" (intermediate access to water), because of its large share of land at the regional scale (45%). In this FS, the most harmful cropping system was input-intensive olive groves intercropped with a melon-pepper/ cereal/ tomato rotation, in which most impacts (35%) were attributable to the input-intensive "melon" crop, and more particularly to "manufacture and transport of fertilizer", including farmyard manure. Globally, the most harmful processes were water and fertilizer use (fertilizer manufacturing and transportation). This downscaling is very useful to inform public policies on the most harmful productions. The impacts in human, ecosystem and resource endpoints increased by 11%, 2%, 9% and 23%, 27% and 40%, for the agrarian and hydrological scenarios respectively.SIGNIFICANCE: These results show that observed trends in farming practices evolution (more irrigation) should be stopped. Our method has three main strengths: i) inter-farms synergies are accounted for in the LCIA, which is essential to promote circularity; ii) thanks to the innovative and multilevel approach, the origins of environmental hotspots can be investigated and later mitigated by future policies; iii) ASD helps to design sustainable scenarios by identifying current trends and regional thresholds (resources, pollution and workforce) that cannot be overcome.

CONTEXT: Policymakers still lack methods to assess the environmental impacts of agriculture at regional scales. Life Cycle Assessment (LCA) is renowned in assessing the environmental footprint of economic activities; however, it has to be adapted to be of use for this purpose.OBJECTIVE: Our objective is to develop a methodology to carry out relevant LCA of agricultural productions at the regional scale, and to address, in particular, two major challenges which are sources of uncertainties in LCA, i.e., data scarcity and farming system diversity.METHODS: We introduce an innovative method for building Life Cycle Inventories (LCI) of agricultural regions, capable of capturing farming system diversity in the context of data scarcity. It combines LCA with Agrarian System Diagnosis (ASD), which has been adapted to meet the heavy data requirements of the LCI step. This method, which we named "ASD-based LCI", was applied to the semi-arid irrigated plain of Kairouan in Tunisia. After ASD is carried out, a typology of farming systems is built using different data sources: literature review and ASD-based data (e.g., historical and landscape analysis, interviews). This paves the way for a stratified sampling of farms, after which each selected farm is studied in-depth, through field visits and extensive interviews, to collect activity data, i.e., data related to energy and material input and output flows (e.g., manure, seeds, electricity) at the crop / livestock level. The data set quality is improved by filling remaining data gaps using various approaches, e.g., analogy, crop modelling, or expert knowledge. The effect of stratified sampling and data gap filling on uncertainty reduction is evaluated using the pedigree matrix approach and the "uncertainty factor" (UF) which determines the uncertainty interval around the mean of any LCI data. RESULTS AND CONCLUSIONS: Nine farming systems including three "corporate agriculture", five "family agriculture" and one "landless farmer" archetypes and seventy cropping and livestock systems were characterized. The pedigree matrix approach showed that with regards to statistics-based data-the uncertainty interval could be reduced twofold, and by a multiple of four with ASD-based LCI, without or with extrapolation, respectively.SIGNIFICANCE: Not only has the ASD-based LCI method proven powerful when building LCI in agriculture at the regional scale with reduced uncertainty, but it is also suited to the quantification of material flow exchanges within the farm and across farms, which is of valuable service when assessing agroecological productions, which promotes circularity.

This study presents a decision support tool that evaluates the environmental efficiency of water reclamation for agricultural irrigation, among other options. The developed tool is published as open source at https://doi.org/10.18167/DVN1/YLP1BA. The objective of this decision support tool is to facilitate the interpretation of the Life Cycle Assessment (LCA) results. This framework was applied to a representative case of reuse of reclaimed water for vine irrigation at the Murviel-Les-Montpellier experimental site (Hérault, France). It was then generalized through modeling assumptions to consider different reuse scenarios. To highlight situations in which the supply of recycled water for irrigation may or may not provide significant environmental benefits, three main parameters were varied: (i) tertiary treatment technologies, (ii) availability of conventional water sources, (iii) energy mix composition. The results show that the environmental impact of reclaimed water depends directly on the type of tertiary treatment technology and the location of the treatment plant in relation to the field and other water sources. The decision support tool has identified where wastewater reuse is clearly an environmentally beneficial source of irrigation among surface and groundwater sources (e.g., WWTP closer to field than river, groundwater too deep, tertiary treatment environmentally beneficial). However, there are many situations where the decision support process cannot distinguish between water reuse for agricultural irrigation and conventional water sources, especially when the nutrient content of treated municipal wastewater is insufficient to offset the negative effects of high energy requirements and chemicals of tertiary treatment.

Effective quantitative and qualitative management of water for irrigation is crucial in many regions and the use of reclaimed water is a possible solution. Quantifying the impact of the use of such water is thus important. Using life cycle assessment methodology, this study analyzes the impact of water reuse irrigation and farmers' practices in greenhouse cucumber production. Three scenarios concerned sources of water for irrigation and agricultural practices: the first scenario used surface water including reclaimed water, the second used groundwater. The third scenario resembled the first but also accounted for fertilizer application based on theoretical cucumber requirements. The third scenario showed 35% less fertilizer is required than the quantities farmers actually use. Our results show that the higher environmental impact of irrigation using reclaimed water than using groundwater is mainly due to over-fertilization. Comparison of the first and third scenarios also showed that the reduction in the environmental impact under the third scenario was significant. We conclude that LCA is a useful tool to compare the impacts of different water sources and farmers' irrigation/fertilization management practices, and in particular, that the quantity of nutrients in reclaimed water should be deducted from the actual amount applied by the farmers.

Boosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi‐factor and multisectoral, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia, Mali, Mozambique, South Africa and Tunisia. The EAU4Food experiences emphasize that actual innovation at irrigated smallholder farm level remains limited without sufficient improvement of the enabling environment and taking note of the wider political economy environment. Most project partners felt at the end of the project that the transdisciplinary approach has indeed enriched the research process by providing different and multiple insights from actors outside the academic field. Local capacity to facilitate transdisciplinary research and engagement with practitioners was developed and could support the continuation and scaling up of the approach. Future projects may benefit from a longer time frame to allow for deeper exchange of lessons learned among different stakeholders and a dedicated effort to analyse possible improvements of the enabling environment from the beginning of the research process. © 2020 The Authors. Irrigation and Drainage published by John Wiley & Sons Ltd on behalf of International Commission for Irrigation and Drainage

Groundwater irrigation is an opportunity to improve yield, but it also brings about a variety of environmental impacts that go beyond the most noticeable impact of water depletion. In this paper, a multi‐criteria environmental impact assessment based on life cycle analysis (LCA) is conducted at the regional level on the Kairouan Plain (Tunisia) where groundwater withdrawals for irrigation purposes are constantly increasing. At this regional level, we have addressed impacts of both groundwater pumping and cropping practices. The diversity of farming and cropping systems was also accounted for.

Most studies on the environmental performance of irrigation have focused on the water-food-energy nexus, i.e. relationships between food production, water consumption and energy. However, water and energy are not the only relevant indicators of the environmental performance of irrigation systems. Life cycle assessment (LCA) is a holistic method that is well suited to comprehensive assessment. This paper aims at using LCA to assess the environmental impacts of contrasted groundwater pumping systems in semi-arid central Tunisia. In line with previous studies, our results confirm that for groundwater pumping, energy has the highest environmental impacts on human health, the ecosystem and resource depletion. Our work also highlights that along with pump efficiency, the type of power source must be considered when ranking pumping systems based on environmental performance. Indeed, diesel-powered pumping systems are more harmful than electric pumps when electricity is generated from natural gas and diesel-powered pump efficiency is low. However, the diesel pumping system becomes the best option when electricity is derived from coal and diesel-powered pump efficiency exceeds 12%. Finally, water depletion has been shown of great importance in this study, and ongoing LCA improvements should facilitate a more comprehensive picture of these site-specific impacts. Copyright (c) 2014 John Wiley & Sons, Ltd.RESUME La plupart des etudes sur la performance environnementale de l'irrigation ont mis l'accent sur le lien eau-alimentation-energie, c'est a dire, les relations entre la production alimentaire, la consommation d'eau et d'energie. Cependant, l'eau et l'energie ne sont pas les seuls indicateurs pertinents de la performance environnementale des systemes d'irrigation. L'Analyse du Cycle de Vie (ACV) est une methode holistique adaptee a l'evaluation globale. Cet article vise a utiliser l'ACV pour evaluer les impacts environnementaux de systemes contrastes de pompage d'eau souterraine, en zone semi-aride, au centre de la Tunisie. En accord avec les etudes anterieures, nos resultats confirment que pour le pompage des eaux souterraines, c'est l'energie qui domine les impacts environnementaux sur la sante humaine, les ecosystemes et l'epuisement des ressources. Notre travail met egalement en evidence que pour classer les systemes de pompage selon leurs performances environnementales, il faut prendre en compte non seulement l'efficience du systeme de pompage mais aussi le type d'energie utilisee. En effet, les systemes de pompage alimentes au diesel sont plus nuisibles que les pompes electriques lorsque l'electricite est produite a partir du gaz naturel et que l'efficience de la pompe est faible. Cependant, le systeme de pompage alimente au diesel devient la meilleure option des lors que l'electricite est produite a partir de charbon et l'efficience de la pompe depasse 12%. Enfin, les impacts sur l'epuisement en eau se sont reveles tres importants dans notre cas d'etude et les avancees methodologiques en cours permettront d'affiner la modelisation de ces impacts de type locaux. Copyright (c) 2014 John Wiley & Sons, Ltd.

Rapidly increasing population growth and food requirements call for increases in agricultural production, especially in irrigated areas. Environmental impacts arising from farming intensification in groundwater irrigated areas worldwide are manifold and the Life Cycle Assessment (LCA) is very relevant for assessing these impacts. But a regional LCA can not be done by transferring the “standard” product-oriented methodology to this meso-scale, especially in a context of data scarcity. Our objective is to propose a methodology to build a regional-scale Life Cycle Inventory (LCI) that would account for farming system diversity, avoid double counting and make clear allocation rules within this multi product system. We propose to base this methodology on the Agrarian System Diagnosis (ASD). This approach leads to a typology of farming systems which reflects the different agricultural exploitation modes existing on a regional scale. Enquiries are then carried out in farms representative of each type in order to build the inventory, which leads to a reduction of the uncertainty. This approach was applied on a case study located in Tunisia. Nine existing farming system archetypes and their main agricultural practices were identified and linked to their natural and socio-economic conditions. This typology goes beyond the farming system structure to describe its functioning and dynamics. Being a valuable approach for building a regional LCI, the agrarian system diagnosis could also be useful when assessing the environmental impacts of agricultural products at farm and crop scale. Indeed, this method allows us to build a typology of realistic situations instead of a virtual average system, and to support better allocation for multi product systems.