Javier Martínez-Dalmau

La agricultura es uno de los principales motores de la escasez y degradación de calidad del agua. Este estudio desarrolla un modelo agroeconómico en dos zonas áridas (Dalías en España y Azraq en Jordania), evaluando la respuesta de la actividad agrícola a diferentes escenarios relacionados con la disponibilidad y la calidad del agua. Se han considerado tres escenarios: disminución constante del agua disponible, tarificación del agua y disminución de la calidad del agua. Los resultados muestran que el modelo es una herramienta adecuada para evaluar las repercusiones de las políticas hídricas. Así, las fuentes de agua alternativas pueden ser una opción viable en Dalías. Sin embargo, las políticas eficaces de tarificación del agua resultan más apropiadas en Azraq.

Se presenta una revisión de los modelos logísticos de difusión de cultivos en agricultura; utilizamos un enfoque de revisión SLR. Nuestro análisis parte de 945 estudios. Tras una exhaustiva revisión resultan 31 trabajos. La difusión es un proceso dinámico de toma de decisiones que en la literatura se vincula estrictamente a la teoría de la utilidad esperada. El modelo logístico es aplicable a la agroindustria, marketing, la industria de telecomunicaciones, la difusión de cultivos agrícolas, etc. Los procesos de difusión presentan un nexo de unión con la dinámica de poblaciones, introducida por Verhulst a mediados del siglo XIX.

Water scarcity and soil salinization pose significant challenges to sustainable agricultural development in arid and semi-arid regions globally. This study applies Positive Mathematical Programming (PMP) to analyze agricultural water resource management in the Hetao Irrigation District (HID), China. The research constructs a comprehensive multi-stress-factor integrated PMP model to evaluate the compound impacts of water resource constraints, pricing policies, and environmental stress on agricultural production systems. The model incorporates crop-specific salinity tolerance thresholds and simulates farmer decision-making behaviors under various scenarios including water supply reduction (0–100%), water pricing increases (0.2–1.0 CNY/m³), and soil salinity stress (0–10 dS/m). The results reveal that the agricultural system exhibits significant vulnerability characteristics with critical thresholds concentrated in the 60–70% water resource utilization interval. Water pricing policies show limited effectiveness in low-price ranges, with wheat demonstrating the highest price sensitivity (−23.8% elasticity). Crop salinity tolerance analysis indicates that wheat–sunflower rotation systems maintain an 85% planting proportion even under extreme salinity conditions (10 dS/m), significantly outperforming individual crops. The study proposes a hierarchical water resource quota allocation system based on vulnerability thresholds and recommends promoting salt-tolerant rotation systems to enhance agricultural resilience. These findings provide scientific evidence for sustainable water resource management and agricultural adaptation strategies in water-stressed regions, contributing to both theoretical advancement of the PMP methodology and practical policy formulation for irrigation districts facing similar challenges.

This research explores the dynamic interplay of water, energy, and carbon in Axarquia, Spain (1990–2030), focusing on the escalating water deficit and rising emissions. It seeks to comprehend the impact of subtropical crop expansion on regional resources. A comprehensive methodology integrates data on water demand, alternative sources and energy-intensive processes. Key methods include assessing the influence of subtropical crops on water requirements by calculating the FAO 56 crop coefficient (Kc), the total annual energy (GWh) as a consequence of the volume of water demanded, identifying the predominant water sources and quantifying CO₂ emissions by calculating the carbon footprint balance, providing a holistic view of regional resource dynamics. The methodology developed here can be adapted to basins elsewhere and can be a useful tool to help the design of water management policies in basins where the balance of the Water, Food, Energy nexus is of particular interest. The study reveals a substantial 30% surge in water demand due to exponential growth in subtropical crops. Additionally, energy-intensive processes linked to alternative water sources contribute to a projected surge in emissions (2022–2030), indicating significant regional challenges. Axarquia faces imminent challenges with a widening water deficit and escalating emissions. However, the region emerges as a vital carbon sink, evidenced by the net carbon balance. With 176,413 tCO₂eq sequestered by cultivated plant mass, the study underscores the potential for environmental improvement and climate change mitigation in the region.

Aim of study: To analyse the diffusion of the crop by producing forecast models, that intend to help farmers in their decision-making. Area of study: Spain. The area dedicated to pistachio cultivation in Spain has multiplied by 36 in the period 2010 to 2020, reaching 44,244 ha. Material and methods: This study brings together data on the evolution of pistachio cultivation based on the following parameters: cultivated area, yield, and price. Methods are based on internal, external influence models and on an influence-price-crop yield pattern. Main results: The results indicate that given a constant crop yield, raising pistachio prices, will bring a production increase that generate the saturation level of the system. Similarly, with a constant pistachio price and an increment of the crop yield, the saturation level of the system increases. Regarding the pattern of influence, it is shown that in a context of suitable market prices for pistachio and an optimal synergy of the production factors that favour the crop yield not only increases the level of saturation of the system but also the duration of the diffusion process. Research highlights: The diffusion curve is sigmoidal with a well-defined inflection point and three well-defined phases. The adoption of pistachio in Spain responds to a model of internal influence (logistic) and never to models of external influence. According to the results, the process has a zero-innovation effect, while the dynamics of the process is completely determined by an imitation effect.

This paper explores the impacts of water pricing as a demand management policy, at a regional level (or basin-sector). To this aim, a hydro-economic model for the Guadalquivir River basin (southern Spain) is proposed here. This basin constitutes a perfect example of a Mediterranean basin subject to frequent and long drought periods, where challenges related to water scarcity are increasing, leading to social conflicts among water users. Moreover, this basin is characterised by a closure state meaning that all available water resources are already allocated among users. In this context, water pricing policy may act as an effective tool to reduce water demand by encouraging changes of behaviour in water users. In particular, those who perform irrigation practices in the agricultural sector. This paper focuses on the irrigation sector since it is the main water user in the basin (87%). Additionally, alternative water-availability scenarios have been used to test the effect of water pricing under drought conditions. The hydro-economic model presented here has been sectorized into four basin sectors with common characteristics (hydro and economic). This enables the analysis of alternative price scenarios in the agricultural sector, in terms of water used, crop patterns and gross margin. Results show that water pricing policy should consider the regional characteristics at the basin-sector scale to gain effectiveness and equity at the river basin scale. Moreover, it has been found that both water availability and the crop pattern at the basin-sector scale have an effect on the reduction of water used (and therefore in gross margin.

This paper explores the impacts of water pricing as a demand management policy, at a regional level (or basin-sector). To this aim, a hydro-economic model for the Guadalquivir River basin (southern Spain) is proposed here. This basin constitutes a perfect example of a Mediterranean basin subject to frequent and long drought periods, where challenges related to water scarcity are increasing, leading to social conflicts among water users. Moreover, this basin is characterised by a closure state meaning that all available water resources are already allocated among users. In this context, water pricing policy may act as an effective tool to reduce water demand by encouraging changes of behaviour in water users. In particular, those who perform irrigation practices in the agricultural sector. This paper focuses on the irrigation sector since it is the main water user in the basin (87%). Additionally, alternative water-availability scenarios have been used to test the effect of water pricing under drought conditions. The hydro-economic model presented here has been sectorized into four basin sectors with common characteristics (hydro and economic). This enables the analysis of alternative price scenarios in the agricultural sector, in terms of water used, crop patterns and gross margin. Results show that water pricing policy should consider the regional characteristics at the basin-sector scale to gain effectiveness and equity at the river basin scale. Moreover, it has been found that both water availability and the crop pattern at the basin-sector scale have an effect on the reduction of water used (and therefore in gross margin.