Superabsorbent hydrogels are a particular class of gels, obtained by chemical stabilization of hydrophilic polymers in a tridimensional network. Hydrogels have been widely proposed over the last 40 years for agricultural use with the aim to ameliorate water availability for plants, by increasing water holding properties of growing media (soils or soilless substrates). Most of the traditional hydrogels on the market are acrylate-based products, thus not biodegradable. Due to the increasing attention for environmental protection issues, biodegradable hydrogels arise lively interest for potential commercial application in agriculture. In this study, we evaluated a novel class of cellulose-based superabsorbent hydrogels, totally biodegradable and biocompatible, for agricultural use. The objectives of the tests carried out were: 1) to verify the ability of the hydrogel to modify the water retention properties of the growing media (soils and soilless substrates); 2) to study the effects on the growth of plants grown on media amended with the hydrogel. Water retention curve of a sandy soil amended with 0, 0.5, 1.0 and 2.0% (w/w) of hydrogel was determined using a Richard's pressure plate apparatus. The hydrogel modified the soil water retention properties. The soil moisture at field capacity increased with the highest hydrogel percentage up to 400% compared to the not amended soil, and at wilting point (-15 bar) was similar to that at field capacity of the not amended soil. When added to perlite, a low water holding capacity soilless substrate, 1 or 2% (w/w) of hydrogel increased the container capacity of 28 and 48%, respectively, with no decrease of air capacity. Tests revealed absence of phytotoxicity of the hydrogel, and cultivation trials on cucumber (on soil) and sweet basil (in soilless conditions) showed a general overall enhancement of plant growth and quality when hydrogel was added to growing media. The tested hydrogel showed to be suitable for potential use in agriculture. Its employment should be further evaluated under a cost-effective perspective. (C) 2015 Published by Elsevier B.V.

Puglia region is particularly rich in agro-biodiversity, representing an example of how local vegetables varieties can still strongly interact with modern horticulture. Unfortunately, the genetic diversity of vegetable crops in this region has been eroded, due to several factors such as abandonment of rural areas, ageing of the farming population, and failure to pass information down the generations. This article summarizes the objectives, methodological approach and results of the project Biodiversity of the Puglia's vegetable crops (BiodiverSO), an integrated project funded by Puglia Region Administration under the 2007-2013 and 2014-2020 Rural Development Program (RDP). Results were reported for each of the eight activities of the project. Moreover, the Polignano carrot (a local variety of Daucus carota L.) was described as a case study, since several tasks have been performed within all eight project activities with the aim of verifying the effectiveness of these actions in terms of safeguarding for this genetic resource strongly linked with local traditions. BiodiverSO is an example of protection and recovery of vegetables at risk of genetic erosion that could help to identify and valorize much of the Puglia's plant germplasm.

Closed cycle soilless techniques can be adopted to minimize water and fertilizer losses in greenhousecultivation. There is a general lack of information regarding the soilless cultivation of vegetables withclosed cycle subirrigation techniques, specifically when using saline water. In this study, a trough benchsubirrigation system (SUB), with two fertilizer concentrations (''100%'', containing 9.8 mol m3 N-NO3,1.6 mol m3 P-H2PO4, 8.7 mol m3 K+, 2.8 mol m3 Ca+, 1.8 mol m3 Mg+, 4 mol m3 S-SO4, and ''70%'',containing 70% of the macronutrient concentration) in the nutrient solution (NS), was compared withopen cycle drip-irrigation (DRIP with ''100%'' NS). For all the three treatments, NS was prepared usingrain water (0.05 dS m1) and adding NaCl (1 g L1), in order to simulate moderate saline irrigation water.The effect of the treatments on tomato (Solanum lycopersicum L.) plant growth, yield, fruit quality, wateruse efficiency (WUE) and fertilizer consumption was evaluated. Substrate and recirculating NScomposition were also studied. Subirrigation, regardless of NS concentration, reduced plant height (by30 cm), leaf area (by 1411 cm2), total fresh and dry weight (by 429 and 48.5 g plant1, respectively) butnot dry matter percentage of the whole plant, with respect to DRIP. Yield was reduced when plants weresubirrigated with the higher concentrated NS, but no differences with open cycle DRIP were recordedwhen the lower NS concentration was used in SUB. Fruit quality was not affected by irrigation system orNS concentration. The higher WUE was obtained with subirrigation. NaCl accumulated similarly over thecrop cycle in recirculating NS of both SUB treatments and in growing substrates of all the threetreatments. Higher salt concentration was found in subirrigated substrates, in particular in the upperpart of the substrate profile. Fertilizers accumulated in the subirrigated substrates when the higher NSconcentration was used, but not when the NS concentration was reduced by 30%. The results of this studyindicate that tomato can be grown successfully in a closed cycle subirrigation system, using saline water,by reducing the fertilizer NS concentration normally used with traditional open cycle systems.

The use of vertical space for the cultivation of plants has origins in the past, but it raises today a renewed interest, both as innovative architectural element (green walls) and both as a system for the production of vegetables (vertical farming). The vertical farming finds its natural application in urban horticulture context, identified by many as an inevitable evolution of the concept of agriculture, motivated by the need to guarantee the satisfaction of the food needs for rapidly growing urban populations. Today, research in the field of vertical farming is focused on solutions with a strong technological connotation, combining the most modern hydroponic closed-cycle cultivation techniques with the intensive use of artificial lighting. While the adoption of these techniques can ensure the most efficient use of resources (water and fertilizers in particular), and higher yield and product quality than any other cultivation system, on the other hand it involves high costs that can slow down the large scale spread of vertical farming. It is therefore necessary to analyze the applicability of vertical farming in the various environmental, cultural and economic scenarios that characterize the different geographic contexts, not forgetting the need to adapt their traditional social and economic models at the base of the current agricultural product production-distribution-consumption system. Also, it should not be overlooked the potential of growing plants in the vertical as a possibility for requalification of fully cementified urban spaces, and as an opportunity for social aggregation and rapprochement with the natural mechanisms of food production.

Sea fennel (Crithmum maritimum L.), an emerging halophyte species, represents a nutritiousand refined food product. In this study, the effect on yield and quality of potted sea fennelgrown on three posidonia (Podisonia oceanica (L.) Delile)-based composts (a municipal organic solidwaste compost, a sewage sludge compost and a green compost) and a peat-based substrate wasanalyzed. Composts were used both pure and mixed with peat at a dose of 50% on a volumebasis. We hypothesized that the halophytic nature of this plant might overcome the limitations ofhigh-salinity compost-based growing media. The growth parameters, color traits and trace metalscontent (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of the edible parts were compared. Independently ofthe substrates, the average total and edible yields were 51 and 30 g plant?1, respectively, while theaverage waste portion was about 41%. The use of posidonia-based compost did not affect the colortraits of sea fennel plants as compared with samples grown on the commercial peat-based substrate.In general, potted sea fennel grown on both posidonia-based composts and commercial peat-basedsubstrate appeared a good source of essential micronutrients. Only a weak reduction of Fe and Mnconcentrations was observed in plants grown on posidonia-based composts, especially when used atthe highest dose. Independently of the growing medium, the content of potentially hazardous traceelements (Cd and Pb) in the edible parts of sea fennel was always below the maximum admissiblelimits fixed by the European legislation. Results indicate that posidonia-based composts can be usedas a sustainable peat substitute for the formulation of soilless mixtures to grow potted sea fennelplants, even up to a complete peat replacement.

In the last decade, among the species proposed for the production of renewable energy, a growing interest has been directed toward the cardoon, due to the high biomass that can be obtained even in marginal environments without irrigation and with low input nitrogen. Studies carried out in Italy and in other Mediterranean countries demonstrated the high variability of the cardoon response in terms of biomass and seed production performance, in relation to the genotype and the cultivation environment. Given the need to use marginal land for bioenergy crops to avoid competition with food crops, a trial in a marginal area of the Sub-Appennino Dauno (southern Italy) was carried out, to identify genotypes that are best suited to this environment and alternative strategies to fulfil crop nitrogen requirements. The trial was carried out during 2012-2013 on a two-year-old crop in rainfed conditions, to compare three nitrogen management strategies and four genotypes: i) unfertilized control (N0), one nitrogen level (50 kg ha-1, N1), and unfertilized with the intercropping with subterranean clover (Trifolium brachycalycinum Katzn. and Morley) in order to exploit the nitrogen-fixing capacity (TB); ii) a wild cardoon (Cynara cardunculus L. var. sylvestris Lamk) landrace (RCT10) and 3 lines (CDL07, CDL09, CDL10) of domestic cardoon (C. cardunculus L. var. altilis DC.). A split plot with three replications experimental design was adopted. Drought during the growing season played a crucial role in the experiment. 'CDL07' performed better in terms of above ground dry biomass (AGDB) with 9.0 Mg ha-1 with respect to the other genotypes (5.4 Mg ha-1, on average). On the contrary, grain yield was the highest in 'RCT10' (2.0 Mg ha-1) and the lowest in 'CDL10' (0.6 Mg ha-1). N1 performed better both for AGDB yield (10.7 Mg ha-1) and seed yield (2.2 Mg ha-1). Conversely, TB provided very low yield (1.4 and 0.2 Mg ha-1, AGDB and seed yield, respectively) because of adverse effect of competition of subterranean clover for water. Results confirmed high variability in biomass and seed yield of different genotypes and the limiting role of the water availability in environments such as those Mediterranean. The intercropping with subterranean clover as eco-sustainable strategy for nitrogen supply is not suitable in dry areas.

In view of increasing water demand by other sectors, and expected reduction ofwater availability in the future, it is necessary to adopt water management strategieswhich aim at water saving while maintaining satisfactory levels of production. One ofthese strategies is to improve water use efficiency through the application of deficitirrigation (DI) which deliberately sustains some degree of water deficit and yieldreduction. The expectation of these strategies is that any yield reduction will be notsignificant as compared with the benefits gained from water saving.Partial root-zone deficit irrigation (PRD) is a DI technique to save irrigation waterwithout much yield reduction. In fact, several authors report that when only part ofthe root system undergoes water-stress, abscissic acid (ABA) may be produced.This is transported through the xylem towards the leaves and reduces stomatalopening. On the contrary, poor root function reduces the production of cytokininswhich are responsible for stomatal opening. These two aspects may combine toreduce stomatal opening and, consequently, gaseous exchange between the leavesand the surrounding environment.This study focused on the effect of DI via PRD on gas exchange, assimilateddistribution, yield, and water use efficiency (WUE), to acquire useful information forthe possible application of this technique on eggplant crop.Research has been carried out in southern Italy to study the split-root water stresseffect on some physiological and morphological parameters of eggplant (Solanummelongena L. cv Tania). Plants were grown in pots and the root system was dividedinto two equal halves by a plastic wall. The pots were put in open air and the soilsurface was covered by a waterproof film to protect the soil from rain water. Thefollowing treatments were compared: 1) the entire rhizosphere (both halves) wellwatered during the whole vegetative cycle (WW); 2) half a rhizosphere well wateredand the other half water stressed after the beginning of blooming until the end ofthe vegetative cycle (WS1); 3) half a rhizosphere well watered and the other halfwater stressed, 30 days later in respect to treatment WS1, and until the end of thevegetative cycle (WS2). It was adopted a randomized blocks layout with 5 replicates.The results showed that stomatal conductance (gs), transpiration and assimilationrate (A) decreased at beginning of partial root water shortage cycle, but after thefirst days of plant adaptation to the new situation, was observed a recovery in this parameters, mainly in A. The reduction of gs is likely to depend not only by the low water potential in the xylem but also by ABA and cytokinins produced by the stressed root system. The shoot/root ratio decreased in PRD plants, mainly in WS1. In PRD plants was observed a reduction in yield, by around 13 (WS1) and 9% (WS2) but, because of lower evapotranspiration experienced by these plants, the WUE increa

Compost has been recently suggested as an alternative to peat for the preparation of growing substrates in soilless cultivation systems. However, some physico-chemical properties of compost may reduce plant performance and endanger the quality of productions, in particular for possible heavy metal accumulation in edible parts. This study aims at evaluating the suitability of a municipal solid waste compost (MSWC) and a sewage sludge compost (SSC) as components of growing media for the soilless cultivation of lettuce (Lactuca sativa L.). Heavy metal content of SSC complied with legislation limits but, in MSWC, it exceeded (Cu, Pb) or was very close (Cd, Zn) to safe limits. A greenhouse experiment was carried out by cultivating four lettuce cultivars ("Maximus," "Murai," "Patagonia," and "Aleppo") in pots containing a mixture of MSWC and perlite (MSWC + P), SSC and perlite (SSC + P), or peat and perlite (peat + P), the latter used as control. Plant biometric parameters measured after 72days of growth revealed that the yield of plants cultivated on SSC + P was similar to control plants, independently of the cultivar. Conversely, MSWC + P suppressed in general the biomass production, especially for Murai and Patagonia cultivars. Compared to peat + P, both compost-based substrates reduced the leaf accumulation of heavy metals, with a major effect in Maximus plants. The levels of Cd and Pb in the edible part were always below the safe limits imposed by European regulation. Therefore, risks of heavy metal intake in food chain associated with the replacement of peat with compost in the growing media are negligible, even when a compost with a significant amount of heavy metals is used. Besides compost quality monitoring, also an appropriate varietal choice is crucial to obtain good yields and safe products.

Irrigated agriculture is dependent on adequate water supply and its quality. Waterused for irrigation can vary greatly in quality, depending upon type and quantity ofdissolved salts. They originate from dissolution or weathering of the rocks and soils,and by intrusion of seawater into the river and underground water resources. Theproblem of saltwater intrusion due to groundwater over-exploitation is one of themajor threats in the coastal areas of Italy, as occurs in Apulia region, where thechronic water shortage forces farmers to use saline irrigation water.Salinity is detrimental for many crops because of its negative effects on the physiologyand production. The salinity tolerance, as well as the genotype, is influenced byseveral agronomic and environmental parameters as air temperature and relativehumidity (RH). Thus, conditions leading to a reduction of transpiration, as lowertemperature and higher RH, can contribute to greater tolerance to salinity. Thus,the techniques that reduce the transpiration rate and heat stress of the crops couldhave a positive effect on salinity tolerance. Among those there is the kaolin-basedparticle film technology (Pft) that employs a multi-functional, environmentally friendlymaterial effective in pest control, mitigation of heat stress, and to produce fruit andvegetables of good quality. The presence of mineral particles over leaves and fruitsurfaces interferes with physiological processes, mainly with heat and radiationbalance and gas exchange.Therefore, it was hypothesized that the Pft could contribute to increasing the salttolerance. In consideration that the tomato, species moderately sensitive to salinity,is a major vegetable crops present in the areas of Apulia at risk of salinity, to verifythe hypotheses, was investigated the effects of Pft on yield and quality, and wateruse efficiency of field grown tomato.The research was carried out in three years on tomato for processing, irrigated withbrackish water, in Southern Italy. Treatments were i) three salinity levels of irrigationwater (Electrical Conductivity of water = 0.5, 5, and 10 dS m-1), ii) tomato plantstreated or not with kaolin, and iii) two cultivars in each year, arranged in a split plotdesign with three replications.The salinity increase caused the reduction in yield mainly for declining fruit weight,but the fruit quality was better in terms of dry matter content and total soluble solids. In addition, salinity increased the blossom-end rot mainly on cultivar with elongated fruits.Pft, overall, as average of three years, improved total (12.7%) and marketable yield (17.7%), fruit weight (8.1%) and harvest index (10.3%), and reduced fruit sunburn by 76.4%. In addition, kaolin contributed to the declining in insect attack to the fruit (58.7%), improvement in total solid soluble (6.2%) and redness (10.2% the skin and 16.6% the pulp) of fruits, and increased yield water use efficiency (Y_WUE

Anaerobic digestion is a technique of growing interest as a promising option for waste disposal and green energy production. The anaerobic effluents (digestate) are a mixture of water (about 95 %) and partially degraded organic matter. Afterwards separation of the two components (liquid and solid), the inorganic ions with a fertilizer value are concentrated mainly in the liquid one. The main limitation to their agricultural use could be the sodium chloride content derived from the initial matrices and the potential phytotoxicity originated from partially decomposed organic matter. In this study the main agrochemical characteristics and the phytotoxicity of eight digestates (derived from co-digestion of posidonia residues with different pretreatments - grinding, washing and autoclave treatments - and a mixture of urban sludges and organic wastes) were evaluated in order to assess their potential use as a source of water and nutrient elements in vegetable seedling production.Lettuce (Lactuca sativa L. var. Ezra) seedlings for transplant were produced on peat based substrate. Digestates liquid fraction (LD), obtained after centrifugation, was used to integrate the nutrient solution at rate of 1:10 v/v; a standard nutrient solution for lettuce seedling cultivation was used as a control (NS). Main chemical properties (pH, EC, inorganic ions content) of LD, shoot and root fresh and dry weight, leaf area, root morphology, root/shoot ratio were determined. Different content of Cl- and Na+ were found in LD in relation to the posidonia residues pre-treatment; moreover LD contained in general high concentration of NH4+, K2+, Mg2+ and Ca2+. Plants cultivated using LD showed a root/shoot ratio (important to ensure good engraftment after transplanting) not significally different from plants grown with NS. The use of LD produced a fresh water saving of 10% and the reduction of mineral fertilizers use. The liquid fraction of digestates could be a good source of macro nutrients and water, and first results indicate that could be re-utilized in relation to its salts content as nutrient solution for lettuce seedling production and likely in soilless cultivation systems.

nel corso della relazione ad invito, i risultati del progetto Life P.R.I.M.E., di cui l'ISPA - CNR ha assunto il coordinamento scientifico, sul tema della gestione razionale dei residui spiaggiati di Posidonia oceanica sono stati presentati all'attenzione di imprenditori, amministratori pubblici e ricercatori interessati all'argomento.

Food plants biofortification for micronutrients is a tool for the nutritional value improvement of food. Soilless cultivation systems, with the optimal control of plant nutrition, represent a potential effective technique to increase the beneficial element content in plant tissues. Silicon (Si), which proper intake is recently recommended for its beneficial effects on bone health, presents good absorption in intestinal tract from green bean, a high-value vegetable crop. In this study we aimed to obtain Si biofortified green bean pods by using a Si-enriched nutrient solution in soilless system conditions, and to assess the influence of boiling and steaming cooking methods on Si content, color parameters and Si bioaccessibility (by using an in vitro digestion process) of pods. The Si concentration of pods was almost tripled as a result of the biofortification process, while the overall crop performance was not negatively influenced. The Si content of biofortified pods was higher than unbiofortified also after cooking, despite the cooking method used. Silicon bioaccessibility in cooked pods was more than tripled as a result of biofortification, while the process did not affect the visual quality of the product. Our results demonstrated that soilless cultivation can be successfully used for green bean Si biofortification.

La presentazione su invito, tenuta nell'ambito della manifestazione Seeds & Chips 2016 nella sessione "Solutions to feeding cities: hydroponics, aeroponics and aquaponics", ha avuto lo scopo di presentare gli avanzamenti scientifici e le competenze dell'ISPA-CNR sul tema della coltivazione con tecniche senza suolo. L'accento è stato posto sulla sostenibilità della coltivazione senza suolo e sulla qualità dei prodotti ottenuti, nel quadro del crescente interesse verso l'orticoltura urbana.

Irrigation is a crucial practice that operators often perform empirically, relying on their own experience, especially in productive areas characterized by low technology agriculture (i.e. several parts of Mediterranean countries). One of the possible approach for proper irrigation scheduling is measuring the soil water potential, simple and easy to manage. The purpose of this research was to examine the effects of two different irrigation regimes (obtained by the use of tensiometer connected to a relay controller) on yield, fruit quality and water consumption of greenhouse tomato (Solanum lycopersicum L. 'Naxos') and cucumber (Cucumis sativus L. 'Sarig' in the first cropping cycle, and 'Mezzo lungo di Polignano', a local landarace, in the second one) grown on a silty-clay soil in Mediterranean conditions. For each species, two tests (August-February and February-July cycle) were carried out in a plastic greenhouse-tunnel. Drip irrigation was adopted, with automated schedule based on tensiometer readings. Two water potential irrigation set-points were compared: -100 and -400 hPa for tomato and -100 and -300 hPa for cucumber, in both cycles. Yield (marketable and unmarketable) and quality traits of fruits (soluble solids, dry matter and titratable acidity) were determined. Water consumption was calculated at the end of each crop cycle. In the first cycle, the two water regimes did not affect the yield of tomato and cucumber. The cucumber irrigated at the lowest soil water potential set-point produced fruits with 8% higher dry matter. In the second cycle, the tomato irrigated at the potential of -400 hPa showed a 40% lower yield (mainly due to the lower fruit size) compared to that of plants irrigated at -100 hPa. The fruits of tomato plants irrigated at -400 hPa, however, showed total soluble solids, dry matter and titratable acidity respectively 41, 45 and 59% higher than -100 hPa. On average, in both crop cycles, a water saving of 35% and 46% on average for tomato and cucumber, respectively, was obtained using the lowest potential as irrigation set-point.Proper use of tensiometer could allow a better use of water resource. Selection of proper water potential set-points according to the cultivation season is crucial for satisfactory results. The positive effects of a controlled and moderate water stress on fruit quality should be taken into account.

Posidonia (Posidonia oceanica [L.] Delile) is a marine phanerogam endemic of the Mediterranean basin. Senescent plant parts periodically detach from and accumulate along Mediterranean beaches, forcing the coastal municipalities to remove and manage somehow the large amount of beached biomass. In this research, a posidonia based compost (posidonia, 63% by volume - olive tree pruning residues, 21% - green waste, 16%) has been used as growing media component at different ratios (0, 25, 50, 75 and 100%), as a complement to a peat based commercial substrate, for nursery lettuce seedlings production. Growing media with increasing compost percentage showed higher pH, EC, air capacity and nutrients availability, but lower water holding capacity. The overall growth of the seedlings was enhanced by the compost presence in the substrate, with positively evidences for both roots and leaves. Posidonia based compost could represent an interesting alternative to peat as horticultural growing media component.

A new sensor for the measurement of electrical conductivity (EC) and moisture content, specifically designed for soilless substrates, has been released (GS3, Decagon Devices). The Hilhorst equation has been proposed as a tool to convert the measured bulk EC (ECb) into the pore EC (ECp, the EC of the solution in the pore spaces of the substrate). A test was carried out to verify the ability of the GS3 sensors to measure changes in the substrate EC under realistic cultivation conditions. Pots, containing tomato plants growing in perlite, were subjected to irrigation for about four weeks with a schedule set to have a leaching fraction of about 90%, which enabled the maintenance of very similar EC in both the root zone and the drainage solutions. A low and a high EC nutrient solution (EC = 2.4 and 4.1 dS/m, respectively) were used in the first and the second half of the test, respectively. The EC of the leachate, used as a measure of the real substrate ECp (ECpreal), the ECb measured by the GS3 sensors and the resulting ECp calculated with the Hilhorst equation (ECpHilhorst) were recorded during the test. The three parameters (ECb, ECpreal and ECpHilhorst) all showed the trend of increasing salinity in the substrate. However, both ECb and ECpHilhorst resulted in different values, in absolute terms, compared to the ECpreal provided by the measurement of the leachate. In particular, the ECpHilhorst values were always lower than ECpreal (0.60 vs 2.48 dS/m and 1.10 vs 4.68 dS/m, on average, respectively in the first and second half of the test).However, the ECpHilhorst was correlated in the tested EC range with the real ECp in the substrate (ECpreal = 4.2815×ECpHilhorst - 0.0766, R2=0.99). According to our results, it seems that GS3 sensors used in perlite are not able to provide accurate values of ECp simply by applying the Hilhorst equation. However, the values provided by the sensor are correlated with the real ECp of the substrate; therefore, using a proper second-step equation can help to convert the obtained value into the real ECp of the substrate.

Closed-cycle management of soilless cultivation is one of the promising strategies to prevent pollution, while increasing the efficiency of water and fertilizer use. However, in order to encourage the adoption of closed-cycle cultivation even in countries characterized by a low-tech greenhouse industry, effective easy-management systems need to be developed.A greenhouse experiment was carried out to determine the influence of two irrigation methods (drip irrigation open-cycle and subirrigation closed-cycle) and two nutrient solution (NS) concentrations (100 and 80% of the macro-element concentration normally used for soilless cultivation) on substrate electrical conductivity (EC), plant growth, gas exchange, yield, fruit quality, and water-use efficiency of green bean (Phaseolus vulgaris L., cv. Saporro). Subirrigated plants showed higher substrate EC and higher Na+ and Cl- concentrations, especially in the upper layer of the growing medium, while moisture distribution throughout the substrate profile showed an opposite trend and was more uniform in drip irrigation. The total fresh and dry biomass of the drip-irrigated plants was higher than in those grown in subirrigation, while whole plant dry matter percentage was lower. Differences in terms of plant height, number of leaves, leaf area, root growth, chlorophyll content, net photosynthesis, stomatal conductance and transpiration rate were recorded, with higher values in drip-irrigated plants. With closed-cycle subirrigation, green bean total and marketable yield (598 and 574 g?plant-1, respectively) were on average 33% lower than for drip irrigation, but fruit quality was higher in terms of "extra class" number of pods (93.6 vs 88.3%) and dry matter percentages. On average, both total and marketable yield were 9% higher with NS 80%, with a 13% higher water consumption, while slight or no effects were observed on net photosynthesis, stomatal conductance and shoot growth. The highest WUE (11.2 kg.m-3) was obtained with subirrigation, where recirculating NS was never discharged, compared to drip irrigation (8.5 kg.m-3). The green bean response to closed-cycle subirrigation showed a general decrease in productive performance. Detrimental effects were reduced by reducing the NS concentration. Lower yield could be compensated by savings of water and fertilizers and lower environmental impact.

Posidonia [Posidonia oceanica (L.) Delile] is a marine phanerogam endemic of the Mediterranean Sea that grows all along the coast forming extensive underwater meadows. Senescent posidonia leaves, together with fibers (residues of rhizomes and decomposed leaves), periodically accumulate along Mediterranean beaches, covering vast areas of coast. Removal and disposal of these large volumes of plant biomasses represent a high cost for local administrations. Therefore, in this experiment, beached residues of posidonia were composted with olive pruning and green wastes with the objective to assess the efficacy of posidonia-based compost (63% on a volume basis) as a peat replacement. The compost was then mixed with a peat-based commercial substrate at rates of 0% (C0, pure peat-based commercial substrate tested as control), 25% (C25), 50% (C50), 75% (C75), and 100% (C100, pure posidonia-based compost) v/v. Mixtures were used as growing media to produce lettuce seedlings for transplant. Two lettuce cultivars (8511RZ and Satine) were tested. Main physical and chemical properties of the five growing media, shoot and root fresh and dry weight, leaf area, root morphology, and elemental leaf tissue composition were studied. Growing media containing posidonia-based compost, C25 and C50 in particular, showed good physical properties. Increasing compost proportions in the mixtures resulted in enhanced: 1) availability of macro- and micronutrients in the growing media; and 2) overall growth parameters of lettuce seedlings, in particular for the cultivar Satine. In conclusion, posidonia-based compost shows a considerable potential as a peat substitute in horticultural substrates; posidonia residues are a low-cost renewable material. In growing media for lettuce seedlings production, posidonia-based compost could be used as a complement to peat at a rate of 25% or 50% to obtain optimal physical properties and to limit the negative effects of high B content, which are typical of posidonia residues.

High quality compost could be used as an environmentally friendly and renewable component for soilless growing media. Beached residues of posidonia (Posidonia oceanica (L.) Delile), a marine phanerogam endemic to the Mediterranean Sea, can be used as raw material for compost production. The aim of this study was to evaluate a posidonia-based compost as a soilless growing medium component for the cultivation of tomato. Beached residues of posidonia (20% in weight) and green wastes were composted. The compost, alone (Compost 100%) or mixed with perlite at the rate of 50% in volume (Per-Comp 50:50), was used as growing medium and compared with traditional perlite (Perlite 100%). Tomato plants (cv. 'Ikram' ungrafted, 'Ikram' grafted onto 'Beaufort' and 'Ikram' grafted onto 'Arnold') were grown in the three growing media. A complete nutrient solution (EC = 1.7 dS/m; pH = 5.0) was used for fertigation. A system composed by EC5 soil moisture sensors, a data logger and a rely controller, and tensiometers to check water potential was used to manage fertigation, with the aim to maintain easily available water. Forty five days after transplanting, the plants grown in 100% compost as well as in the compost/perlite mix resulted in higher growth. Leaf area, total fresh and dry weight increased with increasing amounts of compost in the substrate. The tomato yield in Compost 100% and Per-Comp 50:50 treatments resulted higher than Perlite 100%, in terms of weight and number of fruits (15 and 7%, respectively). Grafted plants, regardless of the rootstock, showed a higher total yield if compared with ungrafted plants (11%, on average). The quality profile of fruits was only slightly influenced by growing media, while was not by the grafting combination. The results show that the compost-based posidonia could be successfully used as soilless substrate component for growing tomato.

Dielectric moisture sensors are particularly suitable for irrigation management in greenhouse soilless production. Identifying the practical effects of substrate water content set-points on crop performance is crucial for successful sensor-based irrigation. We designed and constructed a prototype cloud-connected system for wireless, sensor based irrigation management, and tested it on basil, grown in a perlite-coco (1:1 v:v) soilless substrate under greenhouse conditions. Dielectric moisture/salinity sensors (GS3, Decagon Devices, Pullman - WA, USA) were used. The study, with two subsequent experiments, assessed i) the effects of a progressive decline in substrate water availability, corresponding to moisture levels from water holding capacity to 0.10 m(3) m(-3), on the gas exchange parameters and leaf water status of basil plants; ii) the short-term recovery response of plants when re watered after substrate water content has decreased to different levels; iii) the effects of different irrigation set points (0.40, 0.30 and 0.20 m(3) m(-3)) and leaching rates (approximate to 8% or approximate to 18%) on the basil crop performance over a complete growing cycle. No physiological stress responses were observed on basil plants when moisture level was higher than approximately 0.20 m(3) m(-3), while plants showed drought symptoms at approximately 0.17 m(3) m(-3), corresponding to a substrate matric potential and hydraulic conductivity of -300 hPa and 0.0005 cm day(-1), respectively. Photosynthesis and leaf water potential recovered to values similar to non-stress conditions following a short drought (with moisture level as low as 0.10 m(3) m(-3)). Basil growth was similar when plants were grown with irrigation set-points of 0.40, 0.30 or 0.20 m(3) m(-3) for the complete growing cycle. Fresh weight tended to increase when a higher leaching rate was used, probably because leaching lowered substrate EC. Water use efficiency (basil fresh weight/unit water used) was similar at different irrigation set points and leaching rates. Our results indicate that the use of a wireless sensor network for real-time sensing of substrate water status, combined with precise information on the effects of water availability levels on plants, is an effective tool for precision irrigation management of greenhouse soilless basil.

This study aimed to determine the effects of irrigation management based on matric potential control on growth, plant-water relations, yield, fruit quality traits and water-use efficiency of subirrigated (through bench system) soilless tomato. Tensiometers were used for automatic irrigation control. Two cultivars, 'Kabiria' (cocktail type) and 'Diana' (intermediate type), and substrate water potential set-points (-30 and -60 hPa, for 'Diana', and -30, -60 and -90 hPa for 'Kabiria'), were compared. Compared with -30 hPa, water stress (corresponding to a -60 hPa irrigation set-point) reduced water consumption (14%), leaf area (18%), specific leaf area (19%), total yield (10%) and mean fruit weight (13%), irrespective of the cultivars. At -60 hPa, leaf-water status of plants, irrespective of the cultivars, showed an osmotic adjustment corresponding to a 9% average osmotic potential decrease. Total yield, mean fruit weight, plant water and osmotic potential decreased linearly when -30, -60 and -90 hPa irrigation set-points were used in 'Kabiria'. Unmarketable yield in 'Diana' increased when water stress was imposed (187 vs 349 g?plant-1, respectively, at -30 and -60 hPa), while the opposite effect was observed in 'Kabiria', where marketable yield loss decreased linearly [by 1.05 g?plant-1 per unit of substrate water potential (in the tested range from -30 to -90 hPa)]. Whereas in the second cluster, fruit total soluble solids and dry matter increased irrespective of the cultivars, in the seventh cluster in 'Diana' only a slight increase was observed from -30 vs. -60 hPa (3.3% and 1.3%, respectively, for TSS and dry matter), while in 'Kabiria' the increase was more pronounced (8.7% and 12.0%, respectively, for TSS and dry matter), and further reduction in matric potential from -60 to -90 hPa confirmed the linear increase for both parameters. Both glucose and fructose increased linearly in 'Kabiria' fruits on decreasing the matric potential, while in 'Diana' there was no increase. Control of substrate water status offer the possibility to steer crop response by enhancing different crop-performance components, namely yield and fruit quality, in subirrigated tomato. Small-size fruit varieties benefit more from controlled water stress in terms of reduced unmarketable yield loss and fruit quality improvements.

Posidonia oceanica (L.) Delile is the main marine seagrass endemic of the Mediterranean Sea. From September on, leaves and rhizomes detach off the marine plant and accumulate on beaches in huge amounts, forming banks on the foreshore and backshore of beaches. Offshore residues represent an environmental, economical, social and hygienic problem, because of the great disturbance to the touristic activities, citizens life in urban areas and high costs that the public administrations have to support for managing them (beach cleaning, transport and disposal of such a biomass). Nowadays, current Italian legislation (n. 75/2010) allows the use of posidonia residues as raw material for the production of compost although at a maximum rate of 20% by fresh weight of the composting mixture. High presence of sand mixed to residues after removing from beaches and high salinity levels represent at the moment the main obstacles to the large use of this biomass as raw material for composting. Studies have been conducted, in the framework of the Life09 "Posidonia Residues Integrated Management for Eco-sustainability" (P.R.I.M.E.) project, with the aim to increase the application of posidonia residues for compost production, demonstrating the possibility to effectively separate the sand from the organic material and reduce the salinity levels. Several tests have been carried out with the objective to assess the posidonia-based compost quality. Posidonia-based compost proved to be a good peat substitute for lettuce transplant production and a good growing media component for greenhouse tomato and lettuce in soilless conditions. According to our studies, beached posidonia wastes could represent a low cost and renewable raw material for composting. Posidonia-based compost presents interesting properties and can be used as horticultural growing media component.

The case study focuses on the role that production and consumption of "traditional vegetables" play in the vegetables food-system in Puglia (Southern Italy).Puglia, leading region for intensive horticulture, boasts an enormous heritage of local vegetable varieties, whose cultivation is still widespread and well established in response to demands of local, international and high gastronomy markets, based on their higher quality and the socio-cultural implications associated. However, a significant part of this agro-biodiversity has been lost in the last fifty years, and the threat of continuing to lose it in the future is serious.The traditional vegetables complement the production and the supply of conventional ones, in a much-diversified scenario of production and consumption styles, representing an example of agro-biodiversity protection and cultivation practices calibrated on the characteristics of Mediterranean environments. The policy makers are investing resources on the protection and enhancement of agro-biodiversity, involving research institutions and promoting actions addressed to seed-saver farmers and consumers.The commercial value of these products is supporting the establishment of forms of association between producers, favoring the creation of brands and facilitating the consumption of local products.

Peat is a non-renewable resource and its extraction contributes to the degradation of wetland ecosystems. In order to reduce the peat use in nursery, two composts prepared from yard wastes were evaluated as a substrate component for producing vegetable seedlings for transplantation. Two experiments with tomato (Solanum lycopersicum L.) cultivars 'Naxos' and 'TCP 9147' and pepper (Capsicum annuum L.) cultivars 'Solero' and 'Logos' were set up in a greenhouse. In each experiment two composts were tested: "Cp", obtained from yard wastes + beached residues of marine plant posidonia [Posidonia oceanica (L.) Delile - 20% of total fresh weight], and "C", obtained only from yard wastes. Each compost was mixed with commercial peat in the amount of 0 (control), 25, 50, 75 and 100% (v/v). Results from the study suggest that, for both species, the best yield was obtained with the substrate prepared by mixing the peat with 25% of Cp.

The case study focuses on the role that production and consumption of "traditional vegetables" play in the vegetables food-system in Puglia (Southern Italy).Puglia, leading region for intensive horticulture, boasts an enormous heritage of local vegetable varieties, whose cultivation is still widespread and well established in response to demands of local, international and high gastronomy markets, based on their higher quality and the socio-cultural implications associated. However, a significant part of this agro-biodiversity has been lost in the last fifty years, and the threat of continuing to lose it in the future is serious.The traditional vegetables complement the production and the supply of conventional ones, in a much-diversified scenario of production and consumption styles, representing an example of agro-biodiversity protection and cultivation practices calibrated on the characteristics of Mediterranean environments. The policy makers are investing resources on the protection and enhancement of agro-biodiversity, involving research institutions and promoting actions addressed to seed-saver farmers and consumers.The commercial value of these products is supporting the establishment of forms of association between producers, favoring the creation of brands and facilitating the consumption of local products.

We compared the effects of: 1) timer- ('Timer') and soil moisture sensor-controlled irrigation on soilless lettuce; 2) two volumetric water content (?) thresholds for irrigation (0.30 ('?=0.3') and 0.40 m3?m-3 ('?=0.4')). The most nutrient solution (NS) was applied in 'Timer' where the lowest water use efficiency was observed, with 17 and 42% less NS used in '?=0.4' and '?=0.3', respectively. Irrigation volumes followed the plant water needs in the sensor-controlled treatments, with little or no leaching, while 18% of leaching was recorded in 'Timer'. Plants in 'Timer' and '?=0.4' had higher fresh weights (24%) and leaf area (13%) than plants in ?=0.3. Similar dry weight was observed among treatments but percent dry matter was 20% higher in '?=0.3'. Gas exchanges and leaf tissue chemical composition were similar in all treatments, but nitrate concentration was lower in the '?=0.3' plants. Precision sensor-controlled irrigation based on ? measurements is an effective tool to increase the overall WUE and to improve the quality of soilless-grown lettuce by acting on the substrate moisture level.

The increasing availability of low-cost and reliable substrate moisture sensors offers interesting perspectives for rational and automatic rrigation management of soilless greenhouse crops and for research on plant water relations. The knowledge of the effects of different substrate volumetric water content (VWC) levels on plant growth is crucial for the determination of proper irrigation set-points. An experiment was conducted to assess the effects of different VWC levels on soilless tomato growth and water relations. Tomato plants were grown in a greenhouse in perlite bags. An automatic irrigation system used substrate moisture sensors to control irrigation solenoid valves, in order to keep growing media at four different VWC levels (0.15, 0.20, 0.25 and 0.30 m3?m-3). The system was able to get the substrate VWC at the desired different set-points. Substrate water potential was monitored during the experiment using tensiometers. The four VWC levels resulted, respectively, in a mean substrate water potential of -130, -101, -42 and -34 hPa. Plant growth was similar for plants grown at 0.30 and 0.25 m3?m-3 in terms of leaf area, fresh and dry weight, with higher values than plants grown at 0.20 and 0.15 m3?m-3. Plant water status was affected by the VWC level in the substrate, with higher and similar values of total leaf water potential for plants grown at the two highest VWC levels thanthose grown at lower VWC. The most severe effects of water stress were observed on plants grown at 0.15 m3?m-3 which showed the lowest leaf relative water content (respectively 64.4% vs 84.8% at higher VWC levels) and membrane stability index (respectively 68.6% vs 83.9% at higher VWC levels). The water retention curve and hydraulic conductivity analysis performed on the perlite substrate used in this experiment revealed little or no available water below a VWC of about 0.15 m3?m-3. However, plants grown at 0.15 m3?m-3, were able to uptake water from the growing media and thus to survive, although showing reduced growth and symptoms of water stress. Results seem to confirm that soilless growing media generally hold easily available water in a matric potential range from 0 to -100 hPa, with the majority of free available water present between matric potentials of 0 to -50 hPa.

In literature, the parameters of salinity tolerance of the main cultivated species are known, but are missingfor many minor species such as wild rocket, whose cultivation in many areas of southern Italy affectedby salinity is growing. Therefore, a research has been carried out i) to evaluate the response to salinityin water use, water use efficiency, yield characteristics and morfological features, and ii) identify thesalinity tolerance parameters of two genotypes of wild rocket: Diplotaxis tenuifolia (L.) DC and D. muralis(L.) DC. The study was carried out in the spring of 2007 and 2008 in Policoro (MT), southern Italy, underunheated plastic greenhouse conditions. Wild rocket was sown in plastic pots containing 20 dm3 of soil.For each genotype, six soil salinity levels were compared, obtained by accurately mixing before sowingthe soil with 0.0, 0.5, 1.0, 2.0, 3.5 and 5.5 g dm-3 of NaCl + CaCl2 1:1 (on a weight basis). Irrigation wasperformed with fresh water having electrical conductivity of 0.5 dS m-1. In each year, 3 harvests wereperformed; water use and the main production and plant growth parameters were recorded. D. tenuifoliaprovided a yield 47.3% higher than D. muralis. By rising salinity, progressive decline in marketable yieldand growth of the leaves was recorded, while the dry matter content increased. The increase in salinityhas led to the progressive reduction of water use in both genotypes. From moderate salinity values (about5.5 dS m-1), the reduction in yield water use efficiency as a result of increased salinity has been observed.In addition, salinity reduced specific leaf area and increased leaf succulence. Both genotypes rank amongmoderately salt sensitive species, according to Maas and Hoffman's model (1977). However, D. tenuifolia,with a critical threshold of 1.98 dS m-1 and a slope of 6.61% m dS-1, showed a slightly higher tolerancethan D. muralis (threshold 1.34 dS m-1 and slope 7.25% m dS-1). Reduction in yield due to salinity occurredmainly for the decrease in leaf size and, secondly, number of leaves.