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Controversial figures on environmental impacts associated with urban agriculture are receiving attention from the media and the general public. For comparative analysis, however, methodologically sound evidence is needed, before conclusions can be drawn. In this manuscript, we address issues associated with comparative assessment of environmental performances between rural and urban farming, while also evidencing the need for specifically designed indicators that enable for comprehensive assessment of multifunctional urban agriculture. [ABSTRACT FROM AUTHOR]

Abstract: Efficient use of fertilizers is a main goal that research in agriculture shall address. Dynamic fertilization management is a way of bringing nutrients to the plant when they are crucial for its development. However, destructive measurements of crop nitrogen status are still too costly and time consuming to justify their use, and the implementation of methodologies based upon non-destructive, quick and easy to use tools for plant nutritional status monitoring appears as an appealing opportunity. In this paper vegetation indices based on crop reflectance through the use of a multispectral radiometer (MSR-87, Cropscan Inc.) are compared. Results from three years of experimentation are provided in order to evaluate (a) relations existing between several vegetation indices and both leaf chlorophyll and nitrogen content; (b) the ability of the tool to respond to different nutrient supply and/or (c) to predict yield. A methodological approach for the definition of the most reliable index is proposed and the adopted procedure allows to define the NIR/R560, even with some degrees of incertitude, as the most suitable index for the evaluation of tomato crop nutritional status. [Copyright &y& Elsevier]

In the context of climate change and population growth, aquaculture plays an important role for food security, employment and economic development. Intensive recirculating aquaculture systems (RAS) allow to treat and recycle fish effluents to reduce waste concentration in outflow water thereby reducing environmental contamination. RAS sustainability may be further improved using aquaponics, a circular productive system in which RAS wastewater is recovered for crop cultivation and recycled back to the fish tanks. In this study, water metabolism of a catfish RAS was assessed and the opportunity to produce lettuce with the RAS effluent was tested. Crop growth and water consumption in aquaponics were compared to those experienced in hydroponics at three nutrient solution concentration (EC of 1.6, 2.0 and 3.0 dS∙m−1), also considering water- (WUE) and nitrogen- use efficiency (NUE). A scenario for converting the RAS in a catfish-lettuce aquaponic system was, then, proposed. The RAS water balance included an input of 555 L∙day−1, out of which 32 L∙day−1 were lost by evaporation from the tubs whereas 460 L∙day−1 were discarded. The lettuce yield, NUE and WUE in aquaponics were respectively 20.3%, 22.3% and 20.6% lower than those obtained in hydroponics. Best performances in hydroponics were achieved with EC of 2.0 dS m−1. No difference in term of water consumption arose between the treatments, with average water use of 46 mL∙plant−1∙day−1. Considering the current RAS productivity of 329 kg year−1, a 10 m2 raft system hosting 160 lettuces would satisfy the nitrogen filtration demand. Once closed the water loop between the two productive sub-units, the current water input of 532 L∙day−1 could be reduced to the amount needed to replace the water lost by evaporation (50 L∙day−1) and the RAS water output would decrease from 555 to 103 L∙day−1. Unlabelled Image • Great water losses are associated with conventional aquaculture. • Water metabolism of a catfish aquaculture system was assessed. • Wastewater from aquaculture lacks nutrients to fulfil lettuce requirements. • A scenario for creating a catfish-lettuce aquaponic system was proposed. • A 10 m2 hydroponics allows to recover effluents of a catfish rearing system of 3.3 m3. [ABSTRACT FROM AUTHOR]

Greenhouse crops are often affected by salinity due to water quality decay associated with crop fertilization and irrigation managements as well as the fact that greenhouse environment may become even hotter during summer time. Thus, combined effects of salt, heat and light stresses can affect plants grown in greenhouse. This research work addressed the combined effect of white greenhouse covering film and foliar proline spray application to reduce the detrimental effects of salinity on two cultivars of lettuce ( Lactuca sativa cv. Teide and cv. Impulsion ) grown on a floating system. Five different experiments were conducted in two twin greenhouses covered with plastic films characterized by different light permeability. The experiments aimed at identifying the most suitable nutrient solution (exp. #1), and assessing how the effects of mild salinity (0–15 mM NaCl) would be alleviated by the greenhouse covering film (exp. #2, #3, #4 and #5) and foliar proline spray application (0–15 μM) (exp. #4 and #5). Results showed that the white covering film changed the spectral light intensity and decreased the Photosynthetically Active Radiation (PAR) of the light transmitted causing a delay in the plant growth and leaf chlorophyll content. Although salinity negatively affected plant growth and leaf photosynthesis of both cultivars, using the white film partially mitigated the influence of salt stress. The beneficial effects of the white film on salt stress mitigation were more evident during summer and in the heat sensitive genotype (cv. Teide ) in terms of greater total and marketable yield as compared to control conditions. Exogenous application of foliar proline (up to 5 μM) increased the yield under control condition and enhanced the plant response to salinity. Overall, for summer cultivation of cv. Teide , in presence of saline water (15 mM NaCl), the combination of both white covering film and proline application enabled to preserve efficiently the plant growth and final yield. [ABSTRACT FROM AUTHOR]

Growing conditions and agronomical inputs play a key role in determining fruit qualitative and nutraceutical traits at harvest and post-harvest. The hereby presented research investigated the effects of pre-harvest supplemental LED interlighting on post-harvest quality of hydroponically grown tomatoes (Solanum lycopersicum "Siranzo"). Three LED treatments, applied for 16 h d-1 (h 8.00–00.00), were added to natural sunlight and consisted of Red and Blue (RB), Red and Blue + Far-Red (FR), and Red and Blue + Far-Red at the end-of-day for 30 min (EOD), with an intensity of 180 µmol m-2 s-1 for Red and Blue, plus 44 µmol m-2 s-1 for Far-Red. A control treatment (CK), where plants were grown only with sunlight, was also considered. Fruits at red stage were selected and placed in a storage room at 13 °C in darkness. Fruit quality assessment was performed at harvest time and after one week of storage. RB and FR increased fruit firmness compared to CK, opening possible benefits toward reducing fruit losses during post-harvest handling. RB treated fruits also maintained a higher content of lycopene and β-carotene after the first week of storage. The study demonstrates that supplementary LED interlighting during greenhouse tomato cultivation may enhance storability and help preserve fruit nutritional properties during post-harvest. • Pre-harvest treatments can affect post-harvest quality of tomato. • Supplemental LED light during cultivation affects tomato storage. • Can maintain fruit hardness and carotenoids content. [ABSTRACT FROM AUTHOR]

In this study, plant growth, water relations, ABA levels, ion accumulation patterns and chlorophyll fluorescence were functionally linked to salt stress tolerance of two basil cultivars (Napoletano and Genovese) with different stress sensitivity levels. Plants were treated with salty water at 0, 100 and 200 mM of NaCl. Potential photosynthetic efficiency, non-photochemical quenching and upregulation of photodamage protection by D1 protein revealed higher salt tolerance in Genovese plants, which also resulted in improved water balance and photosynthesis preservation. Upon stress, these plants accumulated also lower ABA and were less affected than Napoletano by salinity in terms of biomass production. Genovese plants were able to upregulate the expression of genes for ROS scavenging and cation transport. These results along with the ability of GEN plants to accumulate larger amount of Na + in the leaf tissue indicate that this cultivar was better suited to partially use Na + as osmoticum. [ABSTRACT FROM AUTHOR]