Search

The use of seawater in horticulture is underestimated. Although pure seawater is harm-ful to most living plants, diluted seawater could represent a promising integration to meet the crop’s nutrient and water requirements. In the current trial, we compared the effects of moderate and high concentrations of seawater and a comparable NaCl solution on a salt-tolerant (Tetragonia tetragonioides) and a salt-sensitive (Lactuca sativa) crop grown in hydroponics. We tested the hy-pothesis that, due to its mineral composition, diluted seawater would result in a less stressful growing medium than NaCl. We observed that diluted seawater resulted in a less detrimental growing medium compared to an EC-comparable NaCl solution, with remarkable differences between the salt-tolerant and the salt-sensitive species. While the growth rates in Tetragonia did not vary between the two types of stress, diluted seawater led to a higher FW and DW biomass yield in the salt-sensitive lettuce compared to the NaCl treatment. Moreover, NaCl reduced the water consumption and water productivity in Tetragonia. In lettuce, NaCl-treated plants demonstrated lower water use efficiency and water productivity compared to the EC-comparable seawater treatment. Physiological parameters and the concentration of mineral elements, phenolics and proline also demonstrated that, due to different mineral composition, seawater is a less stressful growing medium compared to a NaCl solution at comparable EC.

The lack of natural resources, especially good-quality cropland and renewable water resources is threatening food production potential in marginal agricultural ecosystems, which are already negatively affected by climate change. Since the world's major crops are proving inadequate to supply the calories and nutrients for people in these areas, new crops are sought that can withstand harsh ecological environmental conditions. In the current trial, we assessed the growth and productivity of Tetragonia tetragonioides (Pallas) Kuntz. in a floating hydroponic system supplied with different seawater proportions (i.e. 15% and 30% seawater, EC = 9.8 and 18.0 dS m−1). Moreover, the effects of different salinity levels on mineral elements accumulation, production of osmotic solutes and secondary metabolites were determined, along with the salt removal capacity of the crop. The results indicated that plant growth was not affected by either of the seawater treatments used in this study. The increased leaf succulence and the reduction of both leaf area and specific leaf area with increasing salinity might represent an essential feature of this salt-tolerant species associated to the plants need of limiting transpiration. Low seawater treated plants showed a significantly higher biomass yield per liter of (sea)water used (117%) than the control. Under these conditions plants accumulated the highest amount of Mg (+31% and 48% in medium and high seawater treated plants compared with the control) and Cu (+14% and 30%, respectively) along with increasing proline and decreasing nitrate concentrations. By contrast, we found that seawater supply resulted in a Na-enriched leaf biomass that may represent an issue for human health. We concluded that Tetragonia tetragonioides can be grown in saline agriculture up to a salinity level characterized by an EC of 18 dS m-1 but further investigation is required to address Na accumulation in leaves.

The world population is forecast to rise, needing a remarkable increase in food production. As agriculture is among the most water-demanding sectors, such augmentation could negatively affect water resource. Thus actions should be taken both to improve the water efficiency of current cropping systems and to seek alternative water sources for agriculture. The improvement of water efficiency in agriculture has been long investigated. Soilless culture, especially hydroponics, is characterized by a particular attention to the water resource. A different approach is represented by alternative water sources, i.e. seawater, considered as a realistic option in agriculture, either desalinized or blended with freshwater. This study compared the water footprint (WF) of the chicory crop (Cichorium intybus L. var. silvestre) grown in the following cropping systems: a conventional soilless system using freshwater (blue-hydroponics); conventional soil cultivation (blue-pots and open field); a soilless system integrated with a 10% share of seawater (sea-hydroponics); pots irrigated with a 10% share of seawater (sea-pots).By adding seawater to irrigation, we also introduced the "seawater footprint" concept, discussing the environmental implications of the provenience of the irrigation water. Our results showed a significant reduction in WF in both blue-hydroponic and sea-hydroponic (i.e. 64% and 75%, respectively) systems compared to soil cultivation with sea-hydroponics providing the best result in terms of biomass production and water saving. By contrast, sea-pots' performances in terms of WF were significantly lower (at P≤0.05), with an increase of WF of 104% compared to open field cultivation. As the seawater share led to very different results in the two systems, it can be speculated that seawater is not the only reason for the sea-pots' poor performance. Nevertheless, the combination of poor results in terms of both biomass production and water saving and the detrimental effec

To date, the chemical composition and the amount and diversity of volatile organic compounds (VOCs) released by different woody plants samples have been measured and characterized through one of the most common techniques, the gas chromatography–mass spectrometry. However, this technique is very time-consuming and requires sample preparation. By contrast, the Proton-Transfer-Reaction Time-of-Flight Mass spectrometry (PTR-ToF-MS) represents an innovative tool able to provide the whole mass spectra of VOCs with short response time, high mass resolution and without sample preparation. This technique is fast, non-invasive, highly sensitive with a rapid detection system and a very low mass fragmentation of the volatile molecules. The goal of this study was to characterize the VOCs profile of different wood sample cores using a PTR-ToF-MS tool and thereafter to assess whether VOC emissions were specific for some groups of trees. VOCs released from core wood samples belonging to 14 different species were analyzed and subsequently, using an advanced multivariate class-modeling approach, the groups (softwood and hardwood) and the different tree species were discriminated. PTR-ToF-MS was able to detect VOCs from wood and to discriminate between hardwood and softwood and among different species. The great potential and the rapidity of this analysis method allow the PTR-ToF-MS to become a commercial standard tool for monitoring VOCs emitted by wood.

Alternative water sources for irrigation are needed to be found, as agriculture is currently using the 70% of total freshwater. Seawater use for growing crops has long been studied; while an agriculture based on pure seawater is currently impossible, seawater hydroponics may be viable, not aggravating salinization problems in soils. This work aimed at assessing the possibility of growing lettuce, chard and chicory with 3 seawater and freshwater blends (i.e. 5%–10%–15% of seawater). We investigated: i) crops growth, water consumptions, water use efficiency (WUE), water productivity (WP); ii) photosynthetic parameters; iii) principal mineral elements, soluble sugars and phenolics concentration. Lettuce productivity was negatively affected by 10% and 15% of seawater, whereas chard and chicory's growth were not affected by any blend. Interestingly, water consumptions dropped and WUE significantly upturned in every tested crop accordingly with increased seawater concentrations. Leaf concentration of Na+ and of some other ions increased. We concluded that certain amounts of seawater can be practically used in hydroponics, allowing freshwater saving and increasing certain mineral nutrients concentrations.