For the first time, alginate polymer has been applied to prevent dyes from leaching out of colorimetric oxygen indicator films, which enable people to notice the presence of oxygen in the package in an economic and simple manner. The dye-based oxygen indicator film suffers from dye leaching upon contact with water. In this work, UV-activated visual oxygen indicator films were fabricated using thionine, glycerol, P25 TiO2, and zein as a redox dye, a sacrificial electron donor, UV-absorbing semiconducting photocatalyst, and an encapsulation polymer, respectively. When this zein-coated film was immersed in water for 24h, the dye leakage was as high as 80.80±0.45%. However, introduction of alginate (1.25%) as the coating polymer considerably diminished the dye leaching to only 5.80±0.06%. This is because the ion-binding ability of alginate could prevent the cation dye from leaching into water. This novel water-resistant UV-activated oxygen indicator was also successfully photo-bleached and regained colour fast in the presence of oxygen.

International audience | Based on the GRAFS method of biogeochemical accounting for nitrogen (N), phosphorus (P) and carbon (C) fluxes through crop, grassland, livestock and human consumption, a full description of the structure and main functioning features of the French agro-food system was obtained from 1850 to the present at the scale of 33 agricultural regions. For the period since 1970, this description was compared with the results of an agronomic reconstitution of the cropping systems of the Seine watershed based on agricultural census and detailed enquiries about farming practices at the scale of small agricultural regions (the ARSeine database), which were then used as input to an agronomical model (STICS) calculating yields, and the dynamics of N and C. STICS was then coupled with a hydrogeological model (MODCOU), so that the entire modelling chain can thus highlight the high temporal inertia of both soil organic matter pool and aquifers. GRAFS and ARSeine revealed that the agriculture of the North of France is currently characterised by a high degree of territorial openness, specialisation and disconnection between crop and livestock farming, food consumption and production. This situation is the result of a historical trajectory starting in the middle of the nineteenth century, when agricultural systems based on mixed crop and livestock farming with a high level of autonomy were dominant. The major transition occurred only after World War II and the implementation of the Common Agricultural Policy and led, within only a few decades, to a situation where industrial fertilisers largely replaced manure and where livestock farming activities were concentrated either in the Eastern margins of the watershed in residual mixed farming areas or in specialised animal production zones of the Great West. A second turning point occurred around the 1990s when regulatory measures were taken to partly correct the environmental damage caused by the preceding regime, yet without in-depth change of its logic of specialisation and intensification. Agricultural soil biogeochemistry (C sequestration, nitrate losses, P accumulation, etc.) responds, with a long delay, to these long-term structural changes. The same is true for the hydrosystem and most of its different compartments (vadose zone, aquifers, riparian zones), so that the relationship between the diffuse sources of nutrients (or pesticides) and the agricultural practices is not immediate and is strongly influenced by legacies from the past structure and practices of the agricultural system. This has strong implications regarding the possible futures of the Seine basin agriculture.

Based on the GRAFS method of biogeochemical accounting for nitrogen (N), phosphorus (P) and carbon (C) fluxes through crop, grassland, livestock and human consumption, a full description of the structure and main functioning features of the French agro-food system was obtained from 1850 to the present at the scale of 33 agricultural regions. For the period since 1970, this description was compared with the results of an agronomic reconstitution of the cropping systems of the Seine watershed based on agricultural census and detailed enquiries about farming practices at the scale of small agricultural regions (the ARSeine database), which were then used as input to an agronomical model (STICS) calculating yields, and the dynamics of N and C. STICS was then coupled with a hydrogeological model (MODCOU), so that the entire modelling chain can thus highlight the high temporal inertia of both soil organic matter pool and aquifers. GRAFS and ARSeine revealed that the agriculture of the North of France is currently characterised by a high degree of territorial openness, specialisation and disconnection between crop and livestock farming, food consumption and production. This situation is the result of a historical trajectory starting in the middle of the nineteenth century, when agricultural systems based on mixed crop and livestock farming with a high level of autonomy were dominant. The major transition occurred only after World War II and the implementation of the Common Agricultural Policy and led, within only a few decades, to a situation where industrial fertilisers largely replaced manure and where livestock farming activities were concentrated either in the Eastern margins of the watershed in residual mixed farming areas or in specialised animal production zones of the Great West. A second turning point occurred around the 1990s when regulatory measures were taken to partly correct the environmental damage caused by the preceding regime, yet without in-depth change of its logic of specialisation and intensification. Agricultural soil biogeochemistry (C sequestration, nitrate losses, P accumulation, etc.) responds, with a long delay, to these long-term structural changes. The same is true for the hydrosystem and most of its different compartments (vadose zone, aquifers, riparian zones), so that the relationship between the diffuse sources of nutrients (or pesticides) and the agricultural practices is not immediate and is strongly influenced by legacies from the past structure and practices of the agricultural system. This has strong implications regarding the possible futures of the Seine basin agriculture.

Raised-bed plasticulture, an intensive production system used around the world for growing high-value crops (e.g., fresh market vegetables), faces a water-food nexus that is actually a food-water-energy-land-economic nexus. Plasticulture represents a multibillion dollar facet of the United States crop production value annually and must become more efficient to be able to produce more on less land, reduce water demands, decrease impacts on surrounding environments, and be economically-competitive. Taller and narrower futuristic beds were designed with the goal of making plasticulture more sustainable by reducing input requirements and associated wastes (e.g., water, nutrients, pesticides, costs, plastics, energy), facilitating usage of modern technologies (e.g., drip-based fumigation), improving adaptability to a changing climate (e.g., flood protection), and increasing yield per unit area.Compact low-input beds were analyzed against conventional beds for the plasticulture production of tomato (Solanum lycopersicum), an economically-important crop, using a systems approach involving field measurements, vadose-zone modeling (HYDRUS), and production analysis. Three compact bed geometries, 61cm (width)× 25cm (height), 45cm× 30cm, 41cm× 30cm, were designed and evaluated against a conventional 76cm× 20cm bed. A two-season field study was conducted for tomato in the ecologically-sensitive and productive Everglades region of Florida. Compact beds did not statistically impact yield and were found to reduce: 1) production costs by $150–$450/ha; 2) leaching losses by up to 5% (1cm/ha water, 0.33kg/ha total nitrogen, 0.05kg/ha total phosphorus); 3) fumigant by up to 47% (48kg/ha); 4) plasticulture's carbon footprint by up to 10% (1711kg CO2-eq/ha) and plastic waste stream by up to 13% (27kg/ha); 5) flood risks and disease pressure by increasing field's soil water storage capacity by up to 33% (≈1cm); and 6) field runoff by 0.48–1.40cm (51–76%) based on HYDRUS model simulations of 10-year, 2-h storm events in other major tomato production regions of California and Virginia.Re-designing the bed geometries in plasticulture production systems to be more compact is an example of win-win production optimization not only for traditional farms in rural areas but also for urban and peri-urban farms which are located closer to city centers. Compact beds could enable more plants per unit area, thus requiring less land area for the same production. Needing less area facilitates urban and peri-urban farming where land values can be high. Urban and peri-urban farming has several benefits, including reductions in transportation energy as production is closer to market and the ability for city wastewater to be reused for irrigation instead of freshwater withdrawals. Compact beds allow plasticulture to have smaller water, chemical, energy, carbon, waste, and economic footprints without impacting production. Improving agricultural systems in this way could enhance economic and environmental viability, which is essential for a sustainable food-water-energy-land-economic nexus.

The widespread uncertainty regarding future changes in climate, socioeconomic conditions, and population growth have increased interest in water-energy-food-ecology nexus-based frameworks in relation to the analysis of water resources. A challenge for modeling the water-energy-food-ecology nexus is how to reduce the multidimensional and codependent uncertainties and measure the complicated casual relationships effectively. We propose a methodological solution to the problem, and this solution is demonstrated in this case as an extension to the previous water resource optimization framework. We coupled the water-energy-food-ecology nexus into the Bayesian network, which provides a formal representation of the joint probabilistic behavior of the system, and the method was applied to water resource use analysis and management in the Syr Darya River basin, a transboundary and endorheic basin that has contributed to the Aral Sea ecological crisis as a result of unreasonable water use. The annual scale data of four periods, 1970–1980, 1980–1991, 1991–2005, and 2005–2015, were introduced into the Bayesian network. Before the disintegration of the Soviet Union, the amount of water inflow into the Aral Sea was sensitive to increases in irrigation for agricultural development, increases in water storage of the upstream reservoirs and stochastic runoff. After the disintegration of the Soviet Union, the amount of water inflow into the Aral Sea was sensitive to the inefficient irrigation water use in the downstream areas of Uzbekistan and Kazakhstan and the water storage of the reservoir located upstream of Kyrgyzstan. The change resulted from unresolvable disputes between water use for power generation in the upstream area and irrigation in the downstream area. Comprehensive scenario analysis shows that, in the short term, it would be useful to improve the proportion of food crops, improve the efficiency of water use in relation to salt leaching and irrigation, and prevent drought damage. In the long term, based on the increased use of advanced drip irrigation technology from 50% to 80%, the annual inflow into the Aral Sea will increase significantly, reaching 6.4 km³ and 9.6 km³, respectively, and this technology is capable of ameliorating the ecological crisis within the basin.

Raingardens capture and filter urban stormwater using sandy soils and drought-tolerant plants. An emerging question is whether raingardens can also be used as vegetable gardens, potentially increasing their popularity and implementation. A successful vegetable raingarden will need to both retain stormwater and produce vegetables, despite potential water deficits between rainfall events. To determine whether raingardens can provide this dual functionality, we undertook a greenhouse pot experiment using two different substrates (loamy sand raingarden substrate and potting mix typical of containerised vegetable growing) and two methods of stormwater application (‘sub-surface’ and ‘surface’ watering) with the water quantity at each application determined by average Melbourne summer rainfall. Overall, potting mix produced bigger plants (biomass and leaf area) and greater yield than did the loamy sand. Yield effects were variable: tomato yield was unaffected by treatment, bean yield was greatest in potting mix, beetroot yield was greatest with sub-surface watering and parsley yield was greatest with surface watering. Bigger plants also had greater transpiration, which meant that stormwater retention was greatest for parsley and tomato plants growing in potting mix with surface watering. Although, a raingarden with potting mix and surface application of stormwater was optimal for producing food and retaining stormwater under our rainfall regime, potting mix could be problematic due to higher nutrient leaching and breakdown over time. Therefore, we recommend using a mix of loamy sand and potting mix. However, the choice of substrate and watering treatment require trade-offs between yield, stormwater retention and potential implications for water quality and long-term stability of hydraulic properties.

Groundwater pollution with nitrate of agricultural origin is a major problem in many countries. A great deal of effort is focused on finding ways to reduce leaching from agricultural land. In this study, different land management scenarios were evaluated with the SWAT model in order to determine which are the most effective in reducing nitrate leaching on specific soil types in the Krška kotlina alluvial plain (Slovenia). The area is very important both for agriculture production and drinking water resources. The model was calibrated for three soil moisture field trial sites, each representing one major soil type of the area. Simulated soil moisture values were in good agreement with the observed values (PBIAS (percent bias) ±25%). Of the nine land management scenarios that were evaluated, vegetable rotation caused the most nitrate leaching on all soil types, but it fared better on Cambisol than on Fluvisol. Orchards on the other hand leached the least amount of nitrate, but also fared better on Cambisol. Presented studies should be considered as a preliminary stage in the study of nitrate pollution in the investigated area. Results show that nitrate leaching varies for different land management scenarios on different soil types. Further work should concentrate on field trials to evaluate the impacts of reduced fertilization on nitrate leaching and both crop yield and quality on different soil types.