David Martínez-Granados

A three-year field experiment (2021–2023) in southeast Spain evaluated whether reduced mineral fertilization, with or without plant-growth-promoting microorganisms, could maintain crop productivity and modify selected soil indicators in a Mediterranean vegetable rotation. Four treatments were compared: conventional fertilization (T1), reduced fertilization (T2; −30% or −50%), reduced fertilization plus bacterial inoculants (T3), and reduced fertilization plus bacterial–fungal inoculants (T4). Crop yields were not significantly affected by fertilization strategy. Potato yields ranged from 55,661 to 60,741 kg ha⁻¹, those of broccoli from 14,928 to 16,797 kg ha⁻¹, and those of melon from 30,815 to 33,423 kg ha⁻¹. Inoculated treatments were associated with some quality responses, including higher potato tuber firmness in T4 (16.0 vs. 13.2 kg cm⁻² in T1), whereas melon soluble solids tended to be slightly lower. Soil analyses showed changes in some nutrient-related indicators, including a 217% increase in NH₄⁺ in T4 and a 0.75% decrease in pH in T3. Reduced fertilization lowered production costs by about 9%. Under the conditions of this field trial, reduced fertilization maintained yield and gross margin relative to conventional fertilization, and inoculated treatments under reduced fertilization showed differences in selected soil indicators.

This study assesses local stakeholders’ perceptions regarding how a Mediterranean cereal-based cropping system could transition to a more sustainable production, focusing on the identification of the most suitable alternatives for their diversification. Fifty-four stakeholders from the Aragon region in Spain, including farmers, technical advisors, public agricultural officers, local researchers, and experts from environmental NGOs, were consulted. Their responses were analysed using multi-criteria decision-making techniques to order their preferences for different farming practices and diversification strategies. Stakeholders’ responses suggest a priority for balancing soil conservation with the economic viability and continuity of farms. This is evident not only in its consideration as a priority objective but also in their preferences for farming practices, where their implications for farm profitability, especially through the choice of less costly alternatives, are a main concern. This economic rationale also influences their choice of crop diversification alternatives, with a preference for short (two-year) rotations in rainfed cereals and double cropping in irrigated cereals, showing a consideration of the balance between environmental and economic sustainability, and for diversification crops that farmers are already familiar with, aiming both to reduce the uncertainties linked to new crops and to minimise the need for technical support.

Aquifer overdraft is a major environmental and water management problem in Southeast Spain. In some coastal areas, the recent development of desalinisation provides an opportunity to address this problem at a lower social and economic cost. We analyse the economic impact of using several instruments to address this problem in the Alto Guadalentín aquifer: a tax on groundwater pumping, the buyback of groundwater rights and the subsidization of desalinised resources. Their impact is assessed using a mathematical programming model that maximises the farm net margin resulting from the use of the available water resources for irrigation in the area. Our results show that all the alternatives have significant economic impacts, although the availability of desalinised water significantly reduces them. Whereas the outright restriction of non-renewable pumping and an environmental tax have the lowest budgetary cost, they are very unpopular and rather politically unfeasible. Although more expensive for the public budget, purchasing water rights and subsidising desalinised water in exchange for reducing groundwater pumping have the same impact on the agricultural sector, but are likely to be much better received by farmers. Moreover, the former permanently solves the problem.

El aumento continuado de la demanda a nivel mundial de quinoa en la última década está contribuyendo a la expansión de su cultivo fuera de las tradicionales zonas de producción andinas. En España, las principales zonas productoras se sitúan en Andalucía (vegas del Guadalquivir y del Alto Guadalhorce), habiéndose introducido también en zonas de regadío de Castilla y León, Aragón y Cataluña, principalmente. Pese a la ausencia de estadísticas oficiales de precios y estudios de rentabilidad, su expansión sugiere una rentabilidad superior a la de otros cultivos extensivos de regadío. En este artículo se realiza una evaluación de la rentabilidad del cultivo de la quinoa en diferentes zonas de España partiendo de una detallada caracterización técnico‑económica del ciclo de cultivo elaborada a partir de bibliografía y la consulta a técnicos, teniendo en cuenta las diferentes necesidades hídricas que el cultivo presenta en cada zona. Los resultados muestran cómo las labores de cultivo son similares a las de otros cultivos extensivos de regadío y cómo su rentabilidad es significativa, aspectos que indudablemente facilitan su difusión. Asimismo, se muestra cómo la rentabilidad del cultivo es muy sensible al precio del agua de riego, lo que imposibilita su expansión en algunas zonas.

This study assesses the impact of irrigating with desalinated seawater (DSW) on the profitability of greenhouse tomato in south-eastern Spain, comparing different water-quality sources in both traditional sanding cultivation and soilless hydroponic production. The assessment is based on the combination of partial crop budgeting techniques with field data from the LIFE DESEACROP Project experimental activities. Our results show that the exclusive use of DSW for tomato production increases fertilization costs by 20% in soilless systems and by 34% in traditional sanding cultivation, and water costs by 30% in soilless systems and by 48% in traditional soil cultivation. As a result, production costs increase by 5% in soilless cultivation and 3% in soil cultivation, increases that are reduced when DSW is blended with brackish water. However, the lower salinity of DSW, compared with conventional water resources in the area, increases both crop yield and profitability. Soilless cultivation would also increase tomato profitability but only if good quality water is available. The materialization of the potential benefits of soilless production requires improving water quality through the increased use of DSW. Otherwise, the traditional sanding production system, better adapted to the area’s poor soils and bad quality water, would be more profitable.

This study identifies, through consultation with relevant stakeholders, low-input farming practices that can help to minimize the most pressing agronomic and environmental problems in some of the most relevant Mediterranean woody crops in Spain (almond, citrus, and olive) and enhance their sustainability. The results illustrate stakeholders’ perception regarding how each cropping system could be oriented towards a more sustainable production. Despite each case study’s particularities, there is consensus in the need for a shift towards the use of organic fertilizers, the maintenance of vegetation in the edges of plots and the use of integrated pest control strategies. On the contrary, stakeholders have selected different tillage and soil cover practices that are consistent with the characteristics and problems of each cropping system. This study also identifies relevant strengths and drawbacks for the implementation of low-input agricultural practices in each crop and study area. While stakeholders find the identified low-impact farming practices as easy and not costly, suggesting a significant potential for their successful implementation, the results also point out at the reduced knowledge of the practical benefits of some farming practices and the need for improved technical advice to foster the adoption of others.

Spanish authorities have proposed providing external resources to substitute for non-renewable groundwater withdrawals in the south-eastern Murcia Plateau, which would require building new water infrastructure. This article assesses the supply costs and the economic impact of two alternatives, one based on supplying desalinated seawater and the other based on supplying water from the Tagus–Segura Transfer, with an innovative scheme to exchange it for desalinated seawater. It is found that farmers cannot afford the cost of either alternative. Authorities face the dilemma of either strongly subsidizing the external water supply, beyond what seems reasonable, or facing a disproportionate impact on the local economy.

This article assesses the economic impact of implementing a public buyback of groundwater rights to eliminate non-renewable pumping in the Murcia Plateau of the Spanish Segura basin, home of some of the most depleted aquifers in Europe. We find that, regardless of the policy instrument applied, stopping non-renewable extraction would severely hit the agricultural sector. The buyback of rights would not prevent this impact but the cost of reducing extraction would be borne by the government instead of farmers, making it a potentially more successful alternative. However, the estimated cost for the public budget is very large and probably unaffordable.

This paper analyses the cost-effectiveness of combining several economic policy instruments to address the problem of non-renewable pumping in the Alto Guadalentín aquifer in southeastern Spain, one of the most extreme cases of aquifer depletion in Europe. Our results show that all instruments have significant economic impacts. However, the future availability of desalinisation would notably mitigate these impacts, as farmers can substitute groundwater with desalinised water. Although a complete ban on non-renewable pumping and an environmental tax on withdrawals imply the lowest level of public expenditure, they are very unpopular and have a large political cost. The buyback of groundwater rights and the subsidisation of desalinisation in exchange for reducing withdrawals are likely to be much better received by farmers, as their cost would be charged to the public budget. A combination of instruments would split the cost of aquifer recovery between farmers and the administration and would therefore possibly not meet with as much opposition from stakeholders.