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Durum wheat, a staple crop in Italy, faces substantial challenges due to increasing droughts and rising temperatures. This study examines the grain yield, agronomic traits, and quality of 41 durum wheat varieties over ten growing seasons in Southern Italy, utilizing a randomized complete block design. Notably, most varieties were not repeated between trials and 45% of the data was missing. The results indicate that the interaction between genotype and environment (GEI) significantly impacted all traits. High temperatures, elevated vapor pressure deficit (VPD), and water deficits severely affected yield and quality during warm years, while cooler years with favorable water availability promoted better growth and higher yields. Broad-sense heritability (H²) was generally low, suggesting that environmental factors played a major role in the observed traits. However, some traits, such as grain yield, ears per square meter, plant height, bleached wheat, thousand-grain weight, and hectoliter weight exhibited moderate to high heritability of the mean genotype (h²mg), indicating their potential for effective selection in breeding programs. Correlation analyses revealed strong connections between certain traits, such as protein content, and gluten index as well as between grain yield, and spike per square meter. Using the Multi-Trait Mean Performance Selection (MTMPS) index, the study identified six top-performing varieties. Among these, Antalis (G4) and Core (G18) consistently demonstrated strong adaptability and stability across different environments, particularly in hotter, drier conditions. Furio Camillo (G31) also exhibited valuable traits. This study highlights the challenges and complexities of breeding durum wheat for improved yield and quality in the face of climate change.

This study examines the effects of biodegradable mulches on melon production and quality in a Mediterranean environment, specifically focusing on Mater-Bi and Ecovio in comparison to conventional (low-density polyethylene) LDPE mulch. Biodegradable mulches influenced soil temperature, with Mater-Bi maintaining higher maximum soil temperatures conducive to crop growth, while Ecovio exhibited lower maximum temperatures beneficial in hot summer months. Results revealed a significant increase in melon yield with biodegradable mulches, with both Ecovio and Mater-Bi demonstrating higher yields at approximately 20.41 t ha−1, showing an improvement of 23.4% compared to LDPE. Although mulching did not impact the number, weight, or distal diameter of marketable fruits, it affected the apical diameter, with Ecovio-treated plants displaying an 8.4% larger apical diameter compared to the average of all treatments. Furthermore, mulching influenced fruit quality parameters such as consistency, pulp thickness, sugar content, and anti-oxidant activity, with Mater-Bi exhibiting the best performance. Since both Mater-Bi and Ecovio possess strengths and weaknesses, selecting the optimal mulch depends on the farmer’s specific objectives and local growing conditions. Overall, the study suggests that biodegradable mulches, particularly Ecovio, offer a sustainable alternative to traditional plastic films, contributing to environmental preservation and enhancing melon yield and quality in Mediterranean agricultural settings.

Low-density polyethylene (LDPE) mulching films have an important function in crop cultivation; at the end of their life, however, their removal and disposal become both an economic and environmental problem. One possible alternative to low-density polyethylene (LDPE) mulch is provided by certified soil-biodegradable mulch films, such as those produced by Novamont and commercially available under the trade name MaterBi®. MaterBi is a biodegradable thermoplastic material made with starch and a biodegradable copolyester based on proprietary technology. In this study, we compared two biodegradable MaterBi®-based films (commercial and experimental films) with bare soil and a low-density polyethylene to evaluate their effect on yield and on a number of qualitative characteristics (organoleptic and nutraceutical composition) of eggplant fruits (cv Mirabelle F1) grown in two different regions in Southern Italy (Sicily and Campania). In our study, the use of biodegradable MaterBi® films improved not only yield and production parameters, such as the number and average weight of fruits, but also lipophilic and hydrophilic antioxidant activity and phenolic and ascorbic acid content. For many parameters, responses differed according to the cultivation environment and, in particular, the site’s pedoclimatic conditions. Our results suggest that biodegradable MaterBi®-based mulching films are a potentially valid alternative to traditional LDPEs, providing the production and quality benefits reported above and promoting environmental sustainability, thanks to their positive biodegradable properties.

Wheat is one of the most cultivated cereals thanks to both its nutritional value and its versatility to technological transformation. Nevertheless, the growth and yield of wheat, as well as of the other food crops, can be strongly limited by many abiotic and biotic stress factors. To face this need, new methodological approaches are required to optimize wheat cultivation from both a qualitative and quantitative point of view. In this context, crop analysis based on imaging techniques has become an important tool in agriculture. Thermography is an appealing method that represents an outstanding approach in crop monitoring, as it is well suited to the emerging needs of the precision agriculture management strategies. In this work, we performed an on-field infrared monitoring of several durum and common wheat varieties to evaluate their adaptability to the internal Mediterranean area chosen for cultivation. Two new indices based on the thermal data useful to estimate the agronomical response of wheat subjected to natural stress conditions during different phenological stages of growth have been introduced. The comparison with some productive parameters collected at harvest highlighted the correlation of the indices with the wheat yield (ranging between p < 0.001 and p < 0.05), providing interesting information for their early prediction.

Soil secondary salinity due to irrigation is a condition that frequently occurs in Mediterranean areas, and negatively affects crop growth and yield. Biostimulants are proven to alleviate the detrimental effect of salinity on plant growth and production. Four increasing saline concentration levels of water irrigation reaching 6.0 dS m-1 (Electrical Conductivity - EC) were combined with foliar biostimulant treatments (tropical plants and a protein hydrolysate) in pots containing wild rocket. The combined effect of experimental factors improved the SPAD index with greater increases in the EC4 and EC6 plants (+9 and +12% compared to untreated, respectively) but also caused an increase in nitrate content (+48%, on average, compared to the untreated control) without exceeding the EC legal threshold. Overall, for the other parameters analyzed, the response of wild rocket both to application of both salinity and biostimulant was consistent with previous studies. Our results show that biostimulant effectiveness in alleviating the detrimental effect of salinity was not evident for all parameters analyzed. In addition, harvest time affected most parameters, showing the important role of growing conditions in modulating plant response to salinity stress when biostimulants are applied. Plant response thus seems to depend on biostimulant application (type, dose, timing), growing conditions, and genetic traits.

Fruit yield and quality of greenhouse tomatoes are strongly influenced by light conditions and nitrogen (N) availability, however, the interaction between these factors is still unclear. We evaluated the effects on cherry tomatoes of two tunnel plastic covers with different optical properties and three N doses, also in combination with a biostimulant treatment. We compared a diffuse light film (Film1) and a conventional clear film (Film2), and three N levels, corresponding to 50% (N50), 75% (N75) and 100% (N100) of the optimal dose, with and without a microbial plus a protein hydrolysed biostimulant, compared to a non-treated control. The three experimental treatments significantly interacted on several yield and quality parameters. In control plants (untreated with biostimulants), the early yield was higher at reduced N doses compared to N100, with greater increments under the diffusive Film1 compared to the clear Film2 (+57.7% and +37.0% vs. +31.7% and +16.0%, in N50 and N75 respectively). Film1 boosted the total fruit production at all the N rates and with or without biostimulants, compared to Film2, with stronger effects under sub-optimal N (+29.4% in N50, +21.2% in N75, and +7.8% in N100, in plants untreated with biostimulant). Total yield decreased with decreasing N levels, while it always increased with the application of biostimulants, which counterbalanced the detrimental effects of N shortage. Quality traits were mainly affected by the cover film and the biostimulant treatment. The diffusive film increased the content of carotenoids, lycopene and total phenols compared to the clear one, and the biostimulants increased texture, soluble solids, phenols and ascorbic acid compared to the untreated control. It is worth noting that in plants fertilized at 75% of the reference N dose, the biostimulants determined higher yield than the N100 untreated control, under both the covers (+48% in Film1 and +20% in Film2). In conclusion, the diffusive film improved the fruit yield and quality of greenhouse tomatoes in the spring–summer period, presumably avoiding plant stress due to high-intensity direct light. Reduced N rates limited the plant productivity, however, the biostimulant application was effective in compensating for the detrimental effects of sub-optimal supply of N synthetic fertilizers.

The use of biostimulants and biofilms in agriculture is constantly increasing, as they may support plant growth and productivity by improving nutrient absorption, increasing stress resilience and providing sustainable alternatives to chemical management practices. In this work, two commercial products based on Trichoderma afroharzianum strain T22 (Trianum P®) and a seaweed extract from Ascophyllum nodosum (Phylgreen®) were tested on industrial tomato plants (Solanum lycopersicum var. Heinz 5108F1) in a field experiment. The effects of single and combined applications of microbial and plant biostimulants on plants grown on two different biodegradable mulch films were evaluated in terms of changes in the metabolic profiles of leaves and berries. Untargeted metabolomics analysis by LC-MS Q-TOF revealed the presence of several significantly accumulated compounds, depending on the biostimulant treatment, the mulch biofilm and the tissue examined. Among the differential compounds identified, some metabolites, belonging to alkaloids, flavonoids and their derivatives, were more abundant in tomato berries and leaves upon application of Trichoderma-based product. Interestingly, the biostimulants, when applied alone, similarly affected the plant metabolome compared to control or combined treatments, while significant differences were observed according to the mulch biofilm applied.

The aim of the present study is to investigate the effect of differently colored low-density polyethylene mulching films (black, silver/brown, and yellow/brown) in comparison with bare soil (BS) on soil temperatures, yield and yield components (number of fruit and average fruit weight), and fruit quality traits (color, firmness, total soluble solids content, polyphenols, flavonoids, ascorbic acid, carotenoids, and antioxidant activity) of a ‘San Marzano’ tomato crop grown in Southern Italy over two years (2014 and 2015). The warmer season (2015) shortened the cropping cycle (124 vs. 178 days, 2015 vs. 2014), thereby accelerating fruit ripening and improving firmness and redness (on average, the color parameter a/b was greater than in 2014). It determined the best yield response (53 vs. 44 Mg ha−1) by increasing the number of commercial fruits per unit land area despite the lower average fresh weight (AFW) than the first year. Regardless of the different plastic films, in both years, soil heat storage produced by mulching improved yield as compared to BS and showed a positive and significant effect on the contents of total soluble solids, polyphenols, flavonoids, and carotenoids without affecting the antioxidant activity. The highest values of quality traits were reached in the second year with silver and yellow mulches. Therefore, since the colored mulching films (yellow and silver) had a contradictory effect on yield and quality in the two years, further investigation is desirable.

Manipulation of light spectral composition is a useful tool to drive morphological, physiological and metabolic responses in several crops, ultimately improving yield and quality. Novel materials for greenhouse covering are being developed in order to make a better use of the available sunlight: among these are the cover films or panels incorporating fluorescent additives which are able to convert UV solar radiation into visible light. In this research, we compared the physiological traits and the agronomical performance of wild rocket grown in pots in the winter–spring season, under four different greenhouse prototypes covered with poly-methyl-methacrylate (PMMA)-based panels. PMMA panels doped at 3% (Dop3) or 7% (Dop7) w/w with a blend of rare-earth elements (partially converting the solar UV radiation to red and blue wavelengths) were compared with an undoped (UD) and a whitewashed (WW) PMMA greenhouse. The rocket yield was higher in Dop3 (+30%), while it was unaffected in Dop7 and lower in WW (−39%), compared to the control (6.06 kg m−2). The leaf greenness decreased while both the ABTS and the hydrophilic antioxidant activities increased under the doped and the whitewashed greenhouses. The Dop3 treatment provided the best results in terms of yield and quality of greenhouse wild rocket in winter–spring cycle. However, the analysis of OJIP kinetics of chlorophyll fluorescence revealed that the main factor affecting the photosynthetic performance was the light intensity inside each greenhouse rather than the modulation of light spectrum, because of the different shading properties of the doping and whitewashing treatments. Although these results did not allow us to distinguish between the combined effects of shading and light spectrum modulation, the use of photoluminescent covers can be foreseen as a promising innovation in greenhouse horticulture.

Mulching is a common practice for improving crop yield and obtaining an out-of-season production, but when made using plastic materials it can bring environmental problems due to the management and the disposal of films at the end of the cropping seasons. To increase the sustainability of this practice, recently, mulching films made with biodegradable organic materials have become more widely used. Our aim was to evaluate the effect of a biodegradable mulching film on yield and qualitative traits of the San Marzano tomato fruits over two years (2014 and 2015). Two different types of mulching were tested: (i) black biodegradable film (MB12) and (ii) black low-density polyethylene (LDPE) were compared to bare soil (BS). Both mulching films elicited a 25% increase in yield, mainly due to the significantly higher number of fruits per square meter, compared to BS. Both mulching films also elicited a 9.9% increase in total soluble solids and a 57% increase in carotenoid content, while firmness showed the highest value in BS fruits. MB12 determined the highest value of the Hunter color ratio a/b of tomato fruits, followed by LDPE, while the lowest value was recorded in BS fruits. Both mulching films elicited an increase of 9.6%, 26.0%, and 11.7% for flavonoids, polyphenols, and AsA, respectively. In 2014, the MB12 degradation started at 71 days after transplant (DAT); in 2015, at 104 DAT. Therefore, replacing polyethylene with biodegradable film would seem to be an agronomically efficient and environmentally sustainable practice.

Biodegradable films are a valuable and sustainable alternative to plastic films for mulching soils since they avoid the environmental and economic problems related to plastic removal and disposal. Nevertheless, the fast degradation of such materials could make them unsuitable for mid- to long-term use. In a field experiment, the agronomic performance of a biodegradable mulching film (MB) was compared to that of conventional low-density polyethylene (LDPE) film for two consecutive lettuce cycles (winter and spring). In the conditions of this trial, MB showed good resistance to atmospheric agents, with a reduction of its integrity and mechanical properties only after six months. The effects on soil temperature and lettuce yield did not differ from those obtained with LDPE films. The effect on harvest timing was the same as that with LDPE in the spring cycle, while in the winter cycle, the harvest was delayed by about five days compared to LDPE. Mulching films reduced nitrate accumulation in leaves mainly during the winter cycle. However, the effect needs to be further explored with experiments in different pedoclimatic conditions that consider the effects of mulching on nitrification and nitrate-reductase activity that could be affected by changes in soil temperature and moisture. Highlights - Biodegradable mulching films (MB) showed good mechanical resistance in the medium-long term (2 consecutive lettuce cycles). - Decrease in integrity and resistance to tearing became significant after 150-170 days. - The effect of MB on lettuce yield quantity and quality was comparable with that using low-density polyethylene (LDPE) films. - The effects of both mulching films on leaf nitrate content need further research in different pedoclimatic conditions. - MB can be recommended since it reduces the economic and environmental costs of removal and disposal of LDPE films.

Nowadays, biostimulant application is a sustainable practice with which to reduce inputs while maintaining crop yield and quality. Furthermore, the successive harvesting technique is also adopted to increase overall yield and reduce production costs in leafy vegetables. Therefore, a greenhouse experiment was performed to compare four different biostimulants, (i) two from enzymatic hydrolysate of Fabaceae species, (ii) one made from betaine, alginic acid and caidrin, (iii) and another one made from alfalfa extract, algae and molasses rich in low-molecular-weight amino acids, in order to verify their ability to limit nitrate accumulation in wild rocket leaves while boosting yield and quantitative and qualitative components through successive harvests. Successive harvests increased the marketable yield of wild rocket by 41% on average compared to the first harvest, whereas biostimulants treatments increased the yield by 38% on average compared to the control. The SPAD index was increased due to successive harvesting and biostimulant application. While biostimulant application resulted in a 24% decrease in nitrates, it also caused a considerable increase in mineral content in wild rocket leaves. Both biostimulant application and successive harvesting showed promising results, and they could be suggested in leafy vegetable cultivation due to the boosted yield and quality.

Tomato is a great source of bioactive compounds, is important for human health, and is cultivated worldwide. However, the high inputs required for its cultivation must be sustainably managed in order to limit yield losses, thus obtaining high-quality and environmentally friendly production. In this perspective, we compared four biostimulant treatments, i.e., Ascophyllum nodosum extract—Bio; microbial biostimulant containing the micro-organism Trichoderma afroharzianum—Mic; a combination of both—M-B; not treated—Control) and three mulch treatments (biodegradable film Ecovio—ECO; biodegradable film MaterBi®—NOV; bare soil—BS) and evaluated their effects on yield and quality traits in processing tomato. Both biodegradable films elicited a 27.0% yield increase compared to plants grown on bare soil, and biostimulants determined a 23.7% increase over the Control, with the best performance recorded for M-B (+24.8%). Biodegradable MaterBi® film (NOV) was associated with higher total soluble solids (TSS) and firmness values (average of 4.9 °Brix and 1.30 kg cm−2, respectively), even if a significant effect of biostimulants was observed only for the second element. Carotenoid content was higher in non-treated plants grown on bare soil as well as hydrophilic antioxidant activity (AA), but in this case, no differences between biostimulant treatments were recorded. The lipophilic AA in NOV-treated plants was about six and four times higher than observed in BS and ECO treatments, respectively; NOV also caused a 38.7% increase in ascorbic acid content over the Control but was not different from ECO. All biostimulant treatments elicited a 30% increase in phenol content compared to Control plants. Our findings highlight that microbial biostimulants based on A. nodosum extract and T. afroharzianum (both applied singularly and combined) can be considered a sustainable tool for increasing yield and improve some quality traits of processing tomato; in addition, we also confirmed the capability of biodegradable mulches, in particular, MaterBi®, to enhance the agronomic performance of tomato.

The nutrient and nutraceutical quality of greenhouse wild rocket is strongly influenced by the light environment and nitrogen fertilization. We investigated the effects of two cover materials, a diffuse light film (Film1) and a traditional clear film (Film2), and three nitrogen regimes, no N supply (N0) and sub-optimal (N1) and optimal (N2) doses, also in combination with a biostimulant (Stimolo Mo), on the mineral composition, antioxidant properties and chlorophyll and carotenoid content of rocket plants grown in the autumn–spring cycle. The leaf concentration of most of the minerals was higher under Film1 compared to Film2. In general, K, Ca, Mg and Na were higher, and S was lower in the presence of N supply, and the addition of the biostimulant promoted the mineral uptake. Under Film1, the hydrophilic antioxidant activity (HAA) was higher in some harvests, and the ABTS antioxidant activity (ABTS AA) in the first one, while always lower afterward, than under Film2. Nitrogen fertilization did not affect the antioxidant activity, while it reduced the content of total phenols and ascorbic acid. The biostimulant application increased ABTS AA at the optimal N dose and reduced total phenols in unfertilized plants. Both the diffuse light and the N supply inhibited the synthesis of ascorbic acid, while N fertilization and the biostimulant promoted the synthesis of chlorophylls. The experimental treatments exerted variable effects over time and significant interactions with the harvest period were found for many of the investigated parameters.

The availability of irrigation water of good quality is decreasing due to soil salinization and the deterioration of aquifers. Moreover, ongoing climate change severely affects crop production and necessitates the intensification of cropping systems in order to ensure food security at a global scale. For this purpose, the aim of the present study was to evaluate the mitigating effects of two natural biostimulants on Diplotaxis tenuifolia L. plants cultivated at different salinity levels (EC of 0 dS m−1, 2 dS m−1, 4 dS m−1, and 6 dS m−1) and harvested at six consecutive cropping cycles. The tested factors showed a varied combinatorial effect on the tested parameters. These findings indicate the importance of considering growing conditions and cropping periods when applying biostimulants in D. tenuifolia plants under salinity stress. Antioxidant activity and bioactive compounds, such as total phenols, carotenoids, and total ascorbic acid, were variably affected by salinity, biostimulant application, and harvesting time, while mineral profile was also affected by the tested factors depending on the combination of factors. Finally, nitrate content showed decreasing trends with increasing salinity, while biostimulant application resulted in the higher accumulation of nitrates compared to the untreated plants. Although biostimulant application seems to alleviate the negative effects of salinity stress, the effect of growing conditions, as indicated by successive crop cycles, is also important for the response of D. tenuifolia plants to saline conditions and biostimulant application.

Low-density polyethylene (LDPE) plastic mulching films have an important function, but at the end of their lifetime pose an economic and environmental problem in terms of their removal and disposal. Biodegradable mulching films represent an alternative to LDPE with the potential to avoid these environmental issues. In this preliminary study, we employed a biodegradable film based on Mater-Bi® (MB) in comparison with low-density polyethylene to assess their effect on the yield and particular quality traits (organoleptic and nutraceutical composition of the fruits) of muskmelon (cv Pregiato) grown on soils with different textures (clay–loam—CL and sandy loam—SL) in two private farms in South Italy. Soil temperature under the mulch was also measured. During the monitored periods, mean soil temperature under LDPE was higher (about 1.3 °C) than that under the biodegradable film and was higher in SL soil than in CL soil, at 25.5° and 24.2 °C, respectively. However, the biodegradable film was able to limit the daily temperature fluctuation, which was 1.7 °C in both soils compared with 2.3 °C recorded for LDPE. Fruit yields were higher with MB film than LDPE (+9.5%), irrespective of soil texture. MaterBi® also elicited increases in total soluble solids, polyphenols, flavonoids, and antioxidant activity compared with LDPE films: 13.3%, 22.4%, 27.2%, and 24.6%, respectively. Color parameters of flesh, namely brightness, chroma, and hue angle were better in fruits grown on LDPE. Our findings suggest that Mater-Bi® based biodegradable mulching film is a potentially valid alternative to traditional LDPE, particularly for obtaining the agronomical benefits outlined above and for promoting environmental sustainability due to its favourable biodegradable properties.

Rocket species are rich in nutrients with well-known bioactive activity, but their content depends on several factors, such as plant–UV radiation interaction. In this work, we measured the production of nutritional elements in wild rocket (Diplotaxis tenuifolia L.) leaves as a function of exposure to UV-B radiation by adopting a combined approach. The wild rocket plants were grown under three greenhouse cover films (A, B, and C) having different transmittivity to UV-B and the fresh-cut leaves were exposed to UV-B in postharvest for 45, 150, 330, and 660 s. The content of chlorophyll, carotenoids, phenolic compounds, ascorbic acid, and the antioxidant activity were determined. Chlorophyll, carotenoids, and total phenolic content were significantly increased by the combination of Film C and treatment with UV-B for 45 s. The predominant phenolic compounds were kaempferol, isorhamnetin, and quercetin. Film C also elicited an increase in ascorbic acid (the most abundant antioxidant compound in the range 374–1199 per 100 g of dry matter) and antioxidant activity. These findings highlighted an increase in bioactive compound content in the wild rocket when it was cultivated under Film C (diffused light film with a tailored UV-B transmission dose) and treated with UV-B radiation for 45 s postharvest, corresponding to an energy dose of 0.2 KJ m−2.

Supplementary lighting of specific wavelengths can be used for inducing morphological and physiological responses in different crops, ultimately improving yield and quality. Based on this approach, new greenhouse covering materials are being developed in order to improve the use of sunlight in horticulture. These new-generation greenhouse coverings may incorporate light spectrum modulation agents or fluorescent additives which convert solar UV radiation into visible light. In this work, we tested the agronomical and physiological response of lettuce grown under a greenhouse covered with poly-methyl-methacrylate (PPMA) panels doped with a blend of the rare-earth inorganic material with a photo-luminescent effect. The doped greenhouse elicited a 36% increase in lettuce yield compared to the undoped greenhouse. Chlorophyll and carotenoid content, as well as antioxidant activity and ascorbic acid content, were not affected by greenhouse cover, but the doped panels induced a 22% reduction in total phenolics and a 14% increase in nitrate content in leaves. The greenhouse covering materials also affected the photochemistry of photosynthesis, as the daily fluctuations in both the effective quantum yield (ΦPSII) and the electron transport rate (ETR) were attenuated under the doped greenhouse. Non-photochemical quenching (NPQ) was closely related to the light environment in all experimental conditions, with the highest values at 14:00 h. Our results showed that the red-supplemented light spectrum under the doped greenhouse cover contributed to increased plant growth and yield, with a corresponding effect on the physiology of photosynthesis.

Irrigated agricultural lands are prone to salinity problems which may imperil horticultural crops by reducing growth, yield and even qualitative traits. Eco-friendly approaches such as biostimulant application and in particular protein hydrolysates from vegetal origin are implemented to mitigate salinity stress effects on crops. For this reason, a greenhouse experiment on spinach irrigated with increasing concentrations of saline water (EC = 3 dS m−1 (EC3), 6 dS m−1 (EC6) and 9 dS m−1 (EC9), in addition to non-saline treatment (EC0)) was organized, while plants were subjected to foliar applications of a protein hydrolysate from vegetal origin on a weekly basis. The application of this biostimulant helped mitigate the adverse effects of saline stress, by increasing the SPAD index and total chlorophylls of spinach plants. Yield was significantly boosted under biostimulant treatment in saline conditions and reached the value obtained in control treatment (no biostimulants added) × EC0 in the case of EC 3 and 6 dS m−1. In addition, the number of leaves and plants m−1 was increased under biostimulant treatment, and most importantly the hydrophilic antioxidant activity of spinach, thus a qualitative aspect of great importance was also increased. Such results increase the knowledge on the effects of protein hydrolysates application on an important leafy vegetable and may help growers mitigate saline conditions and maintain high crop yield and high quality of the final product when no other source of irrigation water is available.

Durum wheat is often cultivated in marginal areas with great management difficulties. Organic fertilization is a sustainable agricultural practice that allows preserving the environment, but its limit can be the reduction of yield and quality of crops, also in cereals. The aim of research was to evaluate the effects of the organic fertilization on yield and quality of Simeto, a variety of durum wheat, cultivated for two years in three different sites of the internal hill of Campania Region (San Giorgio la Molara, SGM; Ariano Irpino, AI; Sant’Angelo dei Lombardi, SAL). SGM was a sandy-clay-loam soil, with high fertility, while AI and SAL were clay soil. The organic fertilization (ORG), based on roasted leather, was compared to mineral fertilization (MIN) and the not fertilized treatment (N0). In SGM, crop growth rate (CGR) and leaf area index (LAI) were significantly higher than AI and SAL until the flowering (about 2- and 4-fold more, respectively). MIN and ORG significantly boosted CGR compared to N0, while for LAI, ORG was never different from N0. The two-years value of yield was 3.0 t ha–1; in SGM, it reached 4.2 t ha–1, and it was 54.6% more than the mean value of AI and SAL, while N0 was not different from MIN of AI and SAL. ORG yield was lower and not different from NO in AI, where the lowest values of 1000 kernels weight, and hectolitre weight were also recorded. MIN and ORG increased the number of spikes per square meter: 27.0%, and 12.8% over N0, respectively, but ORG showed an 11.2% decrease compared to MIN. The 1000 kernels weight reached the highest values in SAL, without differences between N0, MIN, and ORG. The values of protein and gluten percentage were highest in AI and SGM (about 13.5%, and 11.7%, respectively), but without differences between ORG and MIN in the 3 sites for protein percentage. The worst value of the vitreousness was recorded in SAL (52.3%), six-fold more than that of AI (8.2%), probably due to the high rainfall. NUE reached the highest value in SGM in the first year, when it was significantly different from AI and SAL (0.036 vs 0.030 t kg–1). Overall, the effect of nitrogen fertilization type results sitespecific; indeed, organic fertilization had the same performance of mineral in the site with better soil (low clay content, high nitrogen, and organic matter content) and climate conditions. Highlights - Organic fertilization based on roasted leather was compared to mineral fertilization in three marginal environments for two years. - Effect of organic fertilization on wheat yield, grain quality and nitrogen use efficiency was site-specific. - Yield of plants organically fertilized was lower than mineral fertilization in the two environments less fertile and with a high clay content. - Nitrogen use efficiency of organic fertilization was lower than mineral in the two environments less fertile and with high content of clay. - Grain protein and gluten percentage were lower in the site with higher rainfall.

The use of biostimulants in modern agriculture has rapidly expanded in recent years, owing to their beneficial effects on crop yield and product quality, which have come under the scope of intensive research. Accordingly, in the present study we appraised the efficacy of two plant-derived biostimulants, the legume-derived protein hydrolysates Trainer® (PH), and the tropical plant extract Auxym® (TPE) on two lettuce cultivars (green and red salanova®) in terms of morpho-physiological and biochemical traits (primary and secondary metabolites). The two cultivars differed in their acquisition capacity for nitrate and other beneficial ions, their photosynthetic and transpiration rates, and their ability to synthetize and accumulate organic acids and protective metabolites. The biostimulant effect was significant for almost all the parameters examined but it was subjected to significant cultivar × biostimulant interactions, denoting a cultivar-dependent response to biostimulant type. Notwithstanding this interaction, biostimulant application could potentially improve the yield and quality of lettuce by stimulating plant physiological processes, as indicated by the SPAD index (leaf chlorophyll index), ACO2 (assimilation rate), E (transpiration), and WUEi (intrinsic water use efficiency), and by increasing concurrently the plant mineral content (total N, K, Ca, Mg) and the biosynthesis of organic acids (malate, citrate), phenols (caffeic acid, coumaroyl quinic acid isomer 1, dicaffeoylquinic acid isomer 1), and flavonoids (quercetin-3-O-glucuronide, quercetin-3-O-glucoside). Biostimulant action may facilitate the bio-enhancement of certain lettuce cultivars that are otherwise limited by their genetic potential, for the accumulation of specific compounds beneficial to human health.

Highlights - Municipal solid organic waste compost (MSWC) integrated with N fertilizers can sustain vegetable production. - MSWC (at least 30 t ha-1 d.w.) replaced synthetic fertilizers for tomato and eggplant productions. - N fertilizer integration to the compost residual effect is necessary to sustain endive and broccoli productions. - MSWC (at 15 t ha-1 d.w.) needs 25% of N integration to reduce the gap with plant only fertilized with N fertilizer. - MSWC preserved soil quality and avoided accumulation of undesired metals, such as Cu and Zn. Municipal waste compost was evaluated under open field conditions for replacing synthetic fertilizers in a vegetable three-year succession. Three compost rates, 45 t ha-1, 30 t ha-1 and 15 t ha-1 (dry matter), and compost at 15 t ha-1combined with 25%, and 50% of the full synthetic nitrogen rate, were compared to full and none synthetic nitrogen fertilizations. Crop succession was: tomato followed by endive in the first year; eggplant and, then, broccoli in the second year; tomato and, then, endive/broccoli, in the third year. The application of compost at a dose of at least 30 t ha-1 or at 15 t ha-1 with the addition of 25% of the full synthetic nitrogen rate, in Spring-Summer cycle, sustained growth and yield at levels comparable with those of synthetic nitrogen fertilization. However, only a very poor residual effect of the compost soil treatment on the yield of Autumn-Winter crops, was observed. Monitoring of nitrate content into the soil during cropping seasons, a reduction of the risk of groundwater pollution was displayed due to nitrates released by compost, respect to synthetic nitrogen fertilizer. The cumulative effects of compost application on soil properties were detected at the end of the field trials, registering changes in chemical parameters analyzed, except for phosphorus and boron.

Highlights - The effects of three plant-based biostimulants on yield and quality of processing tomato was explored. - Application of protein hydrolysates and seaweed extract improve marketable yield. - The biostimulants had different effect on nutritional and functional quality of tomato. - Hydrophilic antioxidant activity and ascorbic acid content increased under protein hydrolysate application. Tomato (Solanum lycopersicum L.) is a diffused worldwide vegetable. Great amounts of fertilizers are often applied for increasing yield and quality, without considering the negative effect on the environment. A possible perspective for reducing this risk is to raise the nitrogen use efficiency (NUE) through the use of plant biostimulants, which also improve yield and quality concomitantly. The aim of the current study was to verify the potential beneficial effect of three vegetal-based biostimulants on agronomical, qualitative and nitrogen use efficiency of a processing tomato crop. The experiment provided three biostimulants (an extract of brown seaweed [SwE], a legume-derived protein hydrolysate [LDPH] and a tropical plant extract). The following assessments were carried out: marketable and unmarketable yields, mean fruits weight, firmness, pH, total soluble solids (TSS), color parameters (a/b), hydrophilic antioxidant activity (HAA), lipophilic antioxidant activity (LAA), total ascorbic acid content (AsA), total phenols, nitrate and total nitrogen content, nitrogen use efficiency, N-uptake efficiency, and N-utilization. The foliar application of biostimulants especially protein hydrolysates and seaweed extract significantly affected the marketable yield with an average increase of 18.3% over the control and 41.3% average decrease in unmarketable yield. The N-use and N-uptake efficiency followed a similar trend, with biostimulants boosting it higher than control, +18.4% and +59.3%, respectively; the nitrogen content was also higher in fruits of sprayed plants: + 21.3% over control. This finding also reflects on higher dry matter accumulation and firmness in fruits of treated plants (+10.9% and +14.1% over control, respectively). The biostimulants application, in particular SwE and LDPH, also boosted TSS (+12.8%), the a/b color ratio (+7.5%), HAA and AsA (9.8% and 114.6%, respectively). Therefore, the legume-derived protein hydrolysates and extract of brown seaweed Ecklonia maxima seem a good sustainable approach to improve yield and quality of tomato for canning industries.

Soil erosion is one of the biggest environmental problems throughout European Union causing considerable soil losses. Vegetation cover provides an important soil protection against runoff and soil erosion. To this aim, unlike annual crops, perennial plants have the advantage of covering soil for a longer time and reducing soil erodibility thanks to SOM increase due to litter effect and to reduction of soil disturbance (no-tillage). Two experiments were carried out in marginal hilly areas (10% slope) of Southern Italy: i) long-term experiment in which it was evaluated the effect of two fertilization doses (N: 100 and 50 kg N ha−1 from urea) on Arundo donax L. biomass production as well as its effect on soil erosion; ii) three-year experiment to evaluate the soil cover capacity of the giant reed by analysing the plant leaf area index (LAI). Results of the two experiments showed a good soil protection of Arundo donax L. that reduced soil losses by 78% as compared to fallow and showed soil erosion reduction not different from permanent meadow thanks to the soil covering during the period with the highest rain erosivity and to the reduction in soil erodibility. The protective effect of Arundo donax L. from rain erosivity was also confirmed by LAI analysis that showed a good soil covering of giant reed in the above mentioned period, even during the initial yield increasing phase following crop transplant. According to biomass yield, from the fifteen year of cultivation in a low fertile inland hilly area of Southern Italy, giant reed was characterized by a yield-decreasing phase that resulted postponed as compared to more fertile environments thus ensuring a longstanding soil protection from soil erosion. In addition, the higher nitrogen fertilization dose (100 kg ha−1 of N) allowed interesting biomass yield as compared to the lower dose (50 kg N ha−1) and kept constant SOC along the year of experimentation due to an improved contribution of leaf fall, root exudates and root turnover to soil. Highlights - Soil erosion is an important environmental problem in Mediterranean hilly areas. - Arundo donax L. can significantly reduce soil erosion in hilly cropland. - Soil protection of giant reed is high during the months with higher rain erosivity. - High N inputs enhance giant reed biomass production and soil fertility conservation. - In hilly areas yields are lower but more stable over time than in more fertile environments.

A biennial experiment (2009 and 2010) was conducted at Calvi (Benevento, Southern Italy) to evaluate the effect of compost by organic fraction municipal solid waste (OFMSW), in combination with mineral nitrogen (N) fertilization, on yield and quality of three Dark Fire-cured (Kentucky) tobacco cultivars commonly cultivated at Benevento province (Campania region, Southern Italy). Six N fertilization treatments (N0 = soil N reserves available for plant growth; MIN = 135 kg ha−1 of N applied as mineral fertilizer; C10 = 10 Mg d.w. ha−1 compost; C10N = 10 Mg d.w. ha−1 compost + 50% MIN; C20 = 20 Mg d.w. ha−1 compost; C20N = 20 Mg d.w. ha−1 compost + 50% MIN) were combined with the following cultivars: (i) Foiano, medium early maturing; (ii) Riccio Beneventano (local ecotype), medium maturing; (iii) SKL, medium maturing. Yield of cured leaves (Mg ha−1) and growth components (number of leaves per plant, mean individual leaf area, leaf area per plant, specific leaf weight, stem diameter and height) and color parameters (L*, a*/b*) were measured. Leaf quality traits (nitrates, total N and alkaloids contents, score) and N use efficiency were also determined. The best growth and yield performance was reached in 2010 when plants were taller, developed both stems that were more robust and leaves having greater individual leaf area, and showed a higher leaf area per plant than in the first year. Regardless of the form of applied N (compost, mineral fertilizer, or a combination of both), tobacco plants appeared to be directly and positively influenced by increasing quota of readily available N received by each treatment, which was determined at the beginning of field growth by N soil balance and taking into account the percentage of N supplied by organic (compost) and mineral fertilizers. Results obtained with compost treatments, particularly when combined with mineral fertilizer (at C10N more than C20N), appeared comparable or sometimes better than those of full mineral fertilization although N fertilization by synthetic products was applied at very low doses.

The quantity and quality of wall rocket (Diplotaxis tenuifolia L.) production are strongly influenced by the cultivation system, in particular the protected environment conditions and nitrogen fertilization. In the present research, we tested two greenhouse cover films (Film1: diffuse light; Film2: clear), to verify the effects on yield and nitrate content (a detrimental factor of quality) of rocket leaves, fertilized with optimal (N2) or sub-optimal nitrogen dose (N1), or unfertilized (N0). In addition, we combined the N fertilization with a biostimulant application, declared by the manufacturer as able to reduce nitrate content. Film1 provided a 36% yield increase over Film2 and allowed an increasing production until the V harvest, opposite to what was recorded under Film2, where the yield increased only until the III harvest. Additionally, biostimulant application boosted the yield (+40%), as well as nitrogen fertilization. Both factors had the best performance under Film1, where N1 yield was even equal to N2-Film2. The nitrate content showed a seasonal trend (lower values in spring harvests) and it was boosted by nitrogen (1096, 3696, and 4963 mg/kg fresh weight, for N0, N1, and N2, respectively) and biostimulant application (3924 vs. 2580 mg/kg fresh weight). Therefore, the use of diffuse-light film seems useful to obtain higher yield with a halved N dose as well as in combination with biostimulant application, but the latter did not confirm the capacity to contain nitrate, at least for this crop and in this cultivation system.

Barley is the primary matrix for malting process of beer production. Farmers count on increasing cultivation inputs, especially nitrogen fertilization, in order to reach a higher yield. Nevertheless, an overuse of nitrogen, besides causing environmental damages, can determine a deterioration of quality traits of malting barley, in particular an increase in grains protein content, which should range between 10 and 11% as required by the mating industry. Over two successive years, barley was grown under 4 different nitrogen (N) doses—0 kg N ha−1—N0; 20 kg N ha−1—N20; 40 kg N ha−1—N40 and 60 kg N ha−1—N60, and subject to a biostimulant treatment (Ecklonia maxima seaweed extract). Barley yield and growth parameters increased with nitrogen and seaweed application. N40 was already sufficient in the second year to reach the plateau of the highest production. Biostimulant application increased 17.9% the nitrogen use efficiency, 15.7% the biomass production, and 17.0% the yield with respect to untreated plants. Our results indicate that a significant reduction in nitrogen is possible and desirable, combined with the application of a plant-based biostimulant like seaweed extract, which determines an improvement in nitrogen use efficiency, assuring a higher production and lower fertilization inputs.

Lettuce (Lactuca sativa L.) is one of the most popular leafy vegetables, appreciated globally as a low-calorie food with bioactive compounds. The application of a low dose of abiotic stress is considered a sustainable pre-harvest strategy to modify the nutraceutical value of horticultural products. In this work, we explored the response of two differently colored (red or green) baby leaf lettuce varieties to four NaCl concentrations in the nutrient solution (from 1 to 30 mM), using a full factorial design. We focused on leaf morphological parameters and possible phytochemical enhancement of the main polyphenols and anthocyanins, analyzed by LC-MS. The response to low-to-moderate salt stress exposure was affected mainly by salt concentration for leaf traits or by the cultivar for leaf color, with very limited factors’ interactions. Multivariate analysis indicated a predominant role of the genotypic factor in shaping differences in the two weeks growing cycle for baby leaf lettuce. Phytochemically, different dose–response models to sub-optimal saline conditions may be applied to the various compounds. A significant hormetic stimulation was present only for cyanidin-malonyl glucoside, the main anthocyanin present in the red cultivar.

Tobacco is an annual cash crop widely cultivated over the world, which generally needs great amounts (N) of nitrogen to achieve the best yield and quality. However, with a view to sustainable and environmentally friendly agriculture, also for this crop, the reduction in N fertilization is a priority, but without negatively affecting the yield and quality of the cured product. Therefore, field experiments were conducted during 2002 and 2003 on light air-cured (Burley) tobacco at three different locations of the Campania region (Southern Italy) where high-quality light air-cured (Burley) tobacco is traditionally cultivated. At each location, the following six N fertilization treatments were compared with four replications (blocks): (i) a not fertilized control (N0); (ii) 50 kg N ha−1 (N50); 90 kg N ha−1 (N90); 130 kg N ha−1 (N130); 170 kg N ha−1 (N170); 210 kg N ha−1 (N210). The yield of cured leaves appeared positively influenced by N fertilization but not at a rate higher than 170 kg ha−1. N fertilization directly influenced nitrates and the total N content of cured leaves at all locations. The greater values of both parameters were reached at N130 or N90, respectively, at Vitulazio (CE), N170 at Bellizzi (SA), and N90 at San Giorgio del Sannio (BN). The fire holding capacity increased with N fertilization up to N170 treatment (12–13 s at CE and BN but just 8 s at SA). L* (brightness) decreased with increasing N fertilization giving cured leaves less bright and opaquer. The a/b ratio (a*, green/red; b*, blue/yellow) increased with N treatments producing cured leaves of dark hazelnut. The best scores were assigned to cured products obtained by plants fertilized with 170 kg N ha−1. N-use efficiencies were negatively influenced by N fertilization. The best NUE and N-uptake efficiency was recorded in 2002 at Vitulazio (CE), in spite of a higher NO3-N before N fertilization than other locations.

Promising strategies that could aid a shift from N-intensive agriculture to an eco-friendlier approach include the integrated use of plant-based biostimulants. To date, results about the accumulation of nitrate in green leafy vegetables due to biostimulant application are conflicting. Therefore, the current study aimed at assessing the effect of a new plant-based biostimulant, containing triacontanol (TRIA), that is claimed to reduce nitrate accumulation in leaves, based on the yield and leaf quality of lettuce grown in a plastic tunnel under different N conditions. The experimental design was a factorial combination of three nitrogen fertilization levels (N0, N30, and N60, corresponding to 0, 30, and 60 kg N ha−1) and two biostimulant applications (treated with ‘ILSASTIM+’ = YB and untreated control = NB). Nitrogen fertilization resulted in a 40% yield increase over N0. Biostimulant application increased the yield 21% over NB, and both improved all growth parameters. In addition, the biostimulant had a positive effect on color and Soil Plant Analysis development (SPAD) index, thus enhancing the qualitative aspect. Interestingly, biostimulant application boosted nitrogen use efficiency with a 23% increase over untreated plants. The use of biostimulant proved to be suitable to be applied in a sustainable strategy of production and quality improvement.

Light and nitrogen strongly affect the growth, yield, and quality of food crops, with greater importance in green leafy vegetables for their tendency to accumulate nitrate in leaves. The purpose of this research was to explore the effect of two greenhouse films (Film A and B) on yield, and quality of spinach grown under different nitrogen regimes (not fertilized—N0%; sub-optimal N dose—N50%; optimal N dose—N100%). Film A and Film B were used as clear and diffused light films, with 75% and 87% thermicity, and 85% and 90% total transmittivity, respectively, where only Film B had a UV-B window. Film B elicited an increase in yield (22%) and soil–plant analysis development (SPAD) index (4.6%) compared to the clear film, but did not affect chlorophyll a, b, and total chlorophyll content. In addition, the diffuse film significantly decreased ascorbic acid in the crop but had no effect on lipophilic antioxidant activity and phenols content, but decreased ascorbic acid content. Finally, nitrate content was strongly increased both by nitrogen dose (about 50-fold more than N0%) and greenhouse films (about six-fold higher under diffuse light film), but within the legal limit fixed by European Commission. Therefore, irrespective of N levels, the use of diffuse-light film in winter boosts spinach yield without depressing quality.

Improvements in crop management for a more sustainable agriculture are fundamental to reduce environmental impacts of cropland and to mitigate effects on global climate change. In this study three fertilization types - ammonium nitrate (control); mineral fertilizer added with a nitrification inhibitor (3,4-dimethylpyrazole phosphate (DMPP)), and an organo-mineral fertilizer (OM) - were tested on a tomato crop in order to evaluate effects both on crop production and soil N2O emissions. Plants grown under OM fertilization had a greater relative growth rate compared to mineral fertilization, due to a higher net assimilation rate, which was related to a greater light interception rather than to a higher photosynthetic efficiency. OM fertilization determined the highest fruit production and lower soil N2O fluxes compared to NH4NO3, although the lowest soil N2O fluxes were found in response to mineral fertilizer added with a nitrification inhibitor. It can be concluded that organo-mineral fertilizer is a better nutrient source compared to mineral fertilizers able to improve crop yield and to mitigate soil N2O emission.

A mild salinity stress (eustress) may modulate the induction of the plant defense system in horticultural crops and the synthesis of phytochemical components able to enhance plant resilience, post-harvest performance, and the nutraceutical quality of produce. However, the choice of the correct eustress type and dose to induce the synthesis of these protective phytochemicals is pivotal to avoid potential interference with plant growth and productivity. In order to study how green and red lettuce (Lactuca sativa L.) plants equilibrate the nutritional and nutraceutical components of quality with yield components, we applied iso-osmotic concentrations of three different salts (20 mM NaCl, 20 mM KCl, and 13.3 mM CaCl2, with a final total ionic concentration of 40 mM) in combination with two successive harvests in a floating raft system. The biometric parameters, mineral composition, bioactive compounds, and antioxidant activity of both cultivars were analyzed. The green cultivar had a superior response concerning biometric traits and productivity compared to the red one during the first cut but lower phytochemical content (e.g., ascorbic acid). The effect of cut order, independently of cultivar and salinity treatments, demonstrated that at the first harvest plants could redirect metabolism by increasing the lipophilic antioxidant content (LAA) at the expense of plant yield, therefore increasing plant resilience and post-harvest nutraceutical quality; whereas, at the second harvest, plants reverted principally to tissue expansion. The treatments with iso-osmotic salt concentrations did not affect K and Mg ion contents but further increased LAA and resulted only in a moderate decrease of fresh yield. The lettuce nitrate content was reduced during the second cut only when lettuce plants were treated with NaCl and especially CaCl2.

Hemp (Cannabis sativa L.) is a multipurpose plant attracting increasing interest as a source for the production of natural fibers, paper, bio-building material and food. In this research we studied the agronomical performance of Cannabis sativa cv. Eletta Campana irrigated with saline water. Under those conditions, we tested the effect of protein hydrolysate (PH) biostimulant application in overcoming and/or balancing deleterious salinity effects. The results of the diverse treatments were also investigated at the physiological level, focusing on photosynthesis by means of a chlorophyll a fluorescence technique, which give an insight into the plant primary photochemical reactions. Four salinity levels of the irrigation solution (fresh water–EC0, and NaCl solutions at EC 2.0, 4.0 or 6.0 dS m−1, EC2, EC4 and EC6, respectively) were combined with 2 biostimulant treatments (untreated (control) or treated with a commercial legume-derived protein hydrolysate (LDPH)). The increasing salinity affected plant photochemistry resulting in lower plant growth and seed production, while the LDPH biostimulant showed a protective effect, which improved crop performance both in control and in salinity conditions. The LDPH treatment improved seeds yield (+38.6% on average of all treated plants respect to untreated plants), as well as residual biomass, relevant in fiber production.

Crop management and soil properties affect greenhouse gas (GHG) emissions from cropping systems. Irrigation is one of the agronomical management practices that deeply affects soil nitrous oxide (N2O) emissions. Careful management of irrigation, also concerning to soil type, might mitigate the emissions of this powerful GHG from agricultural soils. In the Mediterranean area, despite the relevance of the agricultural sector to the overall economy and sustainable development, the topic of N2O emissions does not have the same importance as N2O fluxes in temperate agricultural areas. Only some research has discussed N2O emissions from Mediterranean cropping systems. Therefore, in this study, N2O emissions from different soil types (sandy-loam and clay soils) were analyzed in relation to the irrigation of a maize crop grown in two contrasting seasons (2009–2010). The irrigation was done using a center pivot irrigation system about twice a week. The N2O emissions were monitored throughout the two-years of maize crop growth. The emissions were measured with the accumulation technique using eight static chambers (four chambers per site). Nitrogen fertilizer was applied in the form of ammonium sulphate and urea with 3,4 dimethylpyrazole phosphate (DMPP) nitrification inhibitors. In 2009, the N2O emissions and crop biomass measured in both soil types were lower than those measured in 2010. This situation was a lower amount of water and nitrogen (N) available to the crop. In 2010, the N2O fluxes were higher in the clay site than those in the sandy-loam site after the first fertilization, whereas an opposite trend was found after the second fertilization. The soil temperature, N content, and soil humidity were the main drivers for N2O emission during 2009, whereas during 2010, only the N content and soil humidity affected the nitrous oxide emissions. The research has demonstrated that crop water management deeply affects soil N2O emissions, acting differently for denitrification and nitrification. The soil properties affect N2O emission by influencing the microclimate conditions in the root zone, conditioning the N2O production.

The global increasing demand of lettuce is pushing farmers to boost their production through several technical means, including mulching and nitrogen fertilization. However, from an environmental protection perspective, the role of scientific research is to limit the excessive use of some chemical approaches. This research aims to evaluate the possible effects of two mulching films (black polyethylene, PE, and brown photoselective film, BF) and two treatments with a plant growth-promoting product, containing Trichoderma spp., (non-treated, - Control and treated with RYZO PEP UP, - TR), on the productive and qualitative traits of lettuce grown under four regimes of nitrogen (0, 30, 60 and 90 kg ha−1, N0, N30, N60, and N90, respectively). The marketable yield increased at higher nitrogen levels, but without differences between the N60 and N90 doses. The photoselective film elicited marketable yield, with an 8% increase over PE. N fertilization also improved photochemical efficiency (higher Soil Plant Analysis Development and chlorophyllous pigments biosynthesis), as well as antioxidant activities (lipophilic—LAA and hydrophilic—HAA) and bioactive compounds (phenols and total ascorbic acid—TAA). Interestingly, Trichoderma spp. had a positive effect on these qualitative parameters, especially when combined with mulching films, where the increase generated by PE-TR treatment over the all other treatments was 16.3% and 16.8% for LAA and HHA, respectively. In all treatments, the nitrate leaves content was consistently always within the legal limit imposed by the European community. Overall, although Trichoderma spp. did not engender a marked effect on yield, probably due to the short crop cycle, its positive effect on some quality traits is an interesting starting point for further research.

Scientists, extensions specialists, and growers are seeking sustainable agricultural practices that are able to cope with these objectives in order to ensure global food security and minimize environmental damage. The use of mulching films and plant biostimulants in agriculture seems to be a valid solution for tackling these rising concerns. A greenhouse experiment was conducted in order to elucidate the morpho-physiological and nutritive characteristics of lettuce (Lactuca sativa L.) in response to foliar application of a tropical plant extract (PE) biostimulant and the use of plastic mulches. Two biodegradable mulch treatments (Mater-Bi® 1 and Mater-Bi® 2) were compared to black polyethylene (LDPE) and bare soil. Biodegradable mulch film Mater-Bi® 1 produced a comparable marketable fresh yield to the commercial standard polyethylene (LDPE), whereas Mater-Bi® 2 exhibited the highest crop productivity. When averaged over biostimulant application, lettuce plants grown with biodegradable film Mater-Bi® 2 exhibited superior quality traits in terms of K, Ca, total ascorbic acid, and carotenoids content. The combination of film mulching (LDPE, Mater-Bi® 1 or Mater-Bi® 2) with the tropical plant extract biostimulant exhibited a positive and significant synergistic effect (+30%) on yield. The PE-biostimulant induced higher values of SPAD index and total chlorophyll content when compared to untreated greenhouse lettuce. The mineral content of leaf tissues was greater by 10% and 17% (for P and Ca, respectively) when compared to the untreated lettuce (no PE application). Nitrate content was significantly reduced by 23% in greenhouse lettuce plants receiving PE as compared to the untreated control. The positive effect of Mater-Bi® 2 film on the ascorbic acid content has also been highlighted when combined with the biostimulant application, where a major amplification of total ascorbic acid (+168%) was recorded in comparison to the untreated lettuce. Overall, our work can assist leafy vegetables growers in adopting good agricultural practices, such as biodegradable plastic mulches and vegetal-derived biostimulants, to improve the sustainability of greenhouse production.

An optimized nitrogen (N) fertilization may have a positive effect on leafy vegetables by increasing growth, yield and nutrient content of plants. Nevertheless, crop performance must be coupled with an increase in Nitrogen Use Efficiency (NUE) in order to limit external N inputs and to avoid N surpluses associated with environmental and health problems. The aim of the current study was to assess the effects of a legume-derived plant hydrolysates (LDPH; Trainer®) and N fertilization levels (0, 2.25 and 4.5 g N m−2 for spinach and 0, 2.5 and 5.0 g N m−2 for lamb’s lettuce; N0%, N50%, N100%, respectively) on agronomical, biochemical, qualitative responses and NUE of these two important greenhouse leafy vegetables. Spinach and lamb’s lettuce were sprayed four times during the growing period (at a concentration of 4 mL L−1 of LDPH). In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively. Interestingly, in lamb’s lettuce, the N50% plants treated with LDPH reached similar values of marketable yield in comparison to treated and non-treated plants under N100% conditions. The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status. The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively). The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.

The soil salinity increase in the Mediterranean basin is one of the consequences of the climate change. The aim of this study was to evaluate the adaptability of giant reed (Arundo donax L.) to salinity, in conditions of higher temperatures, in order to hypothesise the future use of giant reed under these conditions. The trial was carried out in pots under a permanent metal structure, open on the sides and with a clear PE on the top. Four levels of soil salinity in the range 3.3-15.5 dS m–1 were imposed. The stem number of the most stressed treatment was about 45% lower than the control and also the stem height was lower than in all other treatments. The green and yellow leaf number decreased as the soil salinity increased, and their sum was significantly lower in the two most stressed treatments. Osmotic potential of the leaf sap was not affected by salinity. Leaf water potential and stomatal conduc- conductance in the saline treatments were lower than in the control. tance Assimilation rate showed similar pattern of stomatal conductance. Intrinsic WUE remained almost stable until July and increased during August under the most stressful conditions. PSII photochemistry was not affected by soil salinity. Biomass yield was not different from the control until to soil ECe 12.0 dS m–1: only the most stressed treatment (15.5 dS m–1) caused yield losses (50%). Tolerance threshold to salinity was 11.2 dS m–1 and the relative yield losses were 11.6% per dS m–1.

Cardoon is a crop well adapted to Mediterranean climatic conditions that is able to grow also in marginal lands thus reducing competition for land with food crops. It is considered a key crop for bio-refinery since it allows producing different interesting molecules for industrial application. From stems it is possible to obtain large amounts of cellulose, grains are a good source of oil and proteins and roots can be a source of inulin. The aim of this research has been to evaluate the productive levels of different genotypes of cardoon in two different climatic conditions of Mediterranean cropland (a site in the Vesuvius plain and a site in the internal hilly cropland). In both the sites, during 3 years (from 2012-2013 to 2014-2015), three genotypes (Altilis, Gigante e Trinaseed) were cultivated with 2 planting densities (4 and 8 plants per m2). A low input cropping system was adopted (no irrigation and 150 kg ha–1 of N supplied as ammonium nitrate). In flat site (NA-Ac.), lignocellulosic biomass yield was 19 t ha–1 d.m. and grain yield 2.7 t ha–1 on the average of the 3 years period. In the hilly site, biomass yield was similar (20 t ha–1 d.m.) while grain yield was higher (3.9 t ha–1 on the average) as compared to the flat site. As regards biomass composition, an increase of hemicellulose and a decrease of cellulose content were measured in the flat site, maybe as a response of plant to the higher drought stress.

The depletion of energy resources from fossil fuels and global warming have pushed to consider the agro-energy as one of the renewable energy sources for mitigation of climate change. In this context, agro-energy based on cultivation of energy crops in marginal lands allows to reduce competition with food crops and marginal lands abandonment, producing incomes for farmers. The aim of this work is to improve the knowledge on a promising crop (Arundo donax L.) for the production of bio-energy in marginal lands. Therefore, the behaviour of this crop was evaluated in three study areas of Campania region, under different energy inputs: two levels of nitrogen fertilisation, N100 and N50 in Sant’Angelo dei Lombardi (SA) and Bellizzi (BL). In Acerra (AC) site compost fertilisation was made to verify its effect on pollutant phytoextraction. In the last year, also crop growth analysis was done in the three sites. The results showed that giant reed confirms its adaptability to low fertility soils, allowing interesting biomass yield also in marginal lands. In more fertile environments, effect of fertilisation is not significant at least in the short term. Nevertheless, nitrogen uptake (65-130 kg N ha–1), also if lower than other highyielding crops, needs to be compensated with fertilisation to avoid depletion of soil nutrient reserves and to guarantee sustainability of this cropping system. Giant reed had a positive environmental impact, due to the improvement in soil fertility (soil organic matter and nitrogen increase) and to the mitigation of climate change (C storage in the soil). In marginal soils of Southern Italy this crop confirms an increasing trend of yield during the first 3-4 years. High productivity levels of this crop are related to the extremely high duration of the vegetative period and thus of the photosynthetic activity (from March to November in the Mediterranean area). These last are well expressed by the leaf area duration index, which is more than double than other high-yielding crops such as maize (280 vs 140 days).

Nitrogen is the primary technical means responsible for food production increase, but on the other hand, wise management is needed because its excessive use can have a negative impact on the environment and on green leafy vegetable quality, such as that rocket. Rocket has the characteristics of accumulating nitrate in leaves with possible impacts on human health. In order to overcome this issue, researchers are focusing their attention on the use of alternative means, such as plant biostimulant application. The scope of this study was to assess the effect of legume-derived protein hydrolysate(LDPH) and tropical plant extract(TPE), combined with various doses of nitrogen (0 kg ha−1 non-fertilized; N0); 60 kg ha−1 (sub-optimal; N1); 80 kg ha−1 (optimal; N2); and 100 kg ha−1 (supra-optimal; N3)), in order to reduce nitrogen use, boost yield, and enhance the chemical and nutritional value of leaves without significantly accumulating nitrate. Both vegetal-based plant biostimulants enhanced plant growth, boosted the marketable yield (especially at N0 and N1 levels, by 38.2% and 28.2%, respectively, compared to the non-treated control), and increased the SPAD (Soil Plant Analysis Development) index and leaf pigments content, such as chlorophyll and carotenoids, especially in treated-LDPH rocket. The plant-based biostimulants also produced a major amplification in lipophilic antioxidant activity (+ 48%) and total ascorbic acid content (average + 95.6%), especially at low nitrogen fertilization levels, and maintained nitrate content under the legal European Comission limits.

Nitrogen (N) fertilizers play a crucial role in agriculture, representing a powerful tool for farmers for increasing yields throughout the seasons under both optimal and suboptimal conditions. At the same time, their synthetic/chemical nature could have several influences on ecosystems and human health. For this reason, there is an urgent need to find new and more sustainable means of production to increase plant productivity and optimize nitrogen use. An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop to the foliar application of three plant biostimulants (PBs): Legume-derived protein hydrolysate (LDPH) ‘Trainer®’, tropical plant extract (TPE) ‘Auxym®’ and seaweed extract (SwE) from Ecklonia maxima ‘Kelpak®’ under different N rates of 0, 10, 20 and 30 kg N·ha−1. The responses of baby lettuce plants were assessed in terms of yield, growth parameters and physicochemical composition of the leaves. The fresh yield of baby lettuce in both biostimulant-treated and untreated plants was positively affected by increasing N rates from 0 to 20 kg N·ha−1, reaching a plateau thereafter indicating luxury N conditions at 30 kg N·ha−1. However, high N fertilizer application (20 and especially 30 kg N·ha−1) resulted in undesirable decreases in antioxidant activities and total ascorbic acid (TAA). Under non-fertilized regimens, foliar PBs application boost growth and yield of baby lettuce in comparison to non-treated plants. Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants. Improved agronomical performance of baby lettuce under optimal (10 kg N ha−1) and especially suboptimal N regimens (0 kg N ha−1) was associated with increasing photochemical efficiency and a better activity of photosystem II (higher Soil Plant Analysis Development-SPAD index and chlorophyllous pigments biosynthesis). The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf and did not increased nitrate content as recorded in SwE and TPE treatments. Overall, plant biostimulants may be considered as a sustainable tool of production to increase leafy vegetable productivity in low fertility soils.

Plant-derived protein hydrolysates (PHs) are gaining prominence as biostimulants due to their potential to improve yield and nutritional quality even under suboptimal nutrient regimens. In this study, we investigated the effects of foliar application of a legume-derived PH (0 or 4 mL L−1) on greenhouse baby spinach (Spinacia oleracea L.) under four nitrogen (N) fertilization levels (0, 15, 30, or 45 kg ha−1) by evaluating morphological and colorimetric parameters, mineral composition, carbohydrates, proteins, and amino acids. The fresh yield in untreated and biostimulant-treated spinach plants increased in response to an increase in N fertilization from 1 up to 30 kg ha−1, reaching a plateau thereafter indicating the luxury consumption of N at 45 kg ha−1. Increasing N fertilization rate, independently of PH, lead to a significant increase of all amino acids with the exception of alanine, GABA, leucine, lysine, methionine, and ornithine but decreased the polyphenols content. Interestingly, the fresh yield at 0 and 15 kg ha−1 was clearly greater in PH-treated plants compared to untreated plants by 33.3% and 24.9%, respectively. This was associated with the presence in of amino acids and small peptides PH ‘Trainer®’, which act as signaling molecules eliciting auxin- and/or gibberellin-like activities on both leaves and roots and thus inducing a “nutrient acquisition response” that enhances nutrients acquisition and assimilation (high P, Ca, and Mg accumulation) as well as an increase in the photochemical efficiency and activity of photosystem II (higher SPAD index). Foliar applications of the commercial PH decreased the polyphenols content, but on the other hand strongly increased total amino acid content (+45%, +82%, and +59% at 0, 15, and 30 kg ha−1, respectively) but not at a 45-kg ha−1-rate. Overall, the use of PH could represent a sustainable tool for boosting yield and nitrogen use efficiency and coping with soil fertility problems under low input regimens.

The role of small bioactive molecules (Ocimum basilicum L. cv. Genovese) grown under decreasing NO3−:Cl− ratio (80:20, 60:40, 40:60, or 20:80). Chloride concentration and stomatal resistance increased while transpiration, net CO2 assimilation rate and beneficial ions (NO3−, PO43−, and SO42−) decreased with reduced NO3−:Cl− ratio under the 0 μM OMP treatment. The negative effects of chloride were not only mitigated by the 10 μM OMP application in all treatments, with the exception of 20:80 NO3−:Cl−, but plant growth at 80:20, 60:40, and 40:60 NO3−:Cl− ratios receiving OMP application showed maximum fresh yield (+13%, 24%, and 22%, respectively), shoot (+10%, 25%, and 21%, respectively) and root (+32%, 76%, and 75%, respectively) biomass compared to the corresponding untreated treatments. OMP was not directly involved in ion homeostasis and compartmentalization of vacuolar or apoplastic chloride. However, it was active in limiting chloride loading into the shoot, as manifested by the lower chloride concentration in the 80:20, 60:40, and 40:60 NO3−:Cl− treatments compared to the respective controls (−41%, −37%, and −24%), favoring instead that of nitrate and potassium while also boosting photosynthetic activity. Despite its unequivocally beneficial effect on plants, the large-scale application of OMP is currently limited by the molecule’s high cost. However, further studies are warranted to unravel the molecular mechanisms of OMP-induced reduction of chloride loading to shoot and improved salt tolerance.

Plant biostimulants (PBs) such as protein hydrolysates and seaweed extracts are attracting the increasing interest of scientists and vegetable growers for their potential toenhance yield and nutritional quality. The current study assessed crop productivity, leaf colorimetry, mineral profile and bioactive compounds of greenhouse spinach in response to the foliar application of three PBs: legume-derived protein hydrolysate [PH], extract of seaweed Ecklonia maxima or mixture of vegetal oils, herbal and seaweed Ascophyllum nodosum extracts. Plants were PB-treated at a rate of 3 mL L−1 four times during their growth cycle at weekly intervals. Foliar PB applications enhanced fresh yield, dry biomass and leaf area of spinach in comparison with untreated plants. Improved yield performance with PB applications was associated with improved chlorophyll biosynthesis (higher SPAD index). The three PB treatments elicited an increase in bioactive compounds (total phenols and ascorbic acid), thus raised the functional quality of spinach. The application of PH enhanced K and Mg concentrations and did not result in increased nitrate accumulation as observed with the other two PB treatments. Our findings can assist vegetable farmers and the agro-food industry in adopting innovative and sustainable tools such as PB for complementing a high yield with premium quality.

Little information is available as to the real effectiveness of the phytoextraction remediation technique, since laboratory experiments are still the most common way in which this is measured. Given this, an experiment on a cadmium-polluted soil was carried out in open field conditions in Southern Italy with the aim of assessing the growth and the phytoextraction potential of giant reed (Arundo donax L). Compost fertilisation and Trichoderma harzianum A6 inoculations were used to verify the possibility of increasing the metal uptake of the crop. Biomass yield of giant reed in the first growth season (average 12.8 Mg ha–1) was not affected by the Cd concentration in the soil and this increased significantly with compost fertilisation (13.8 Mg ha–1). Both compost fertilisation and T. harzianum inoculation increased cadmium uptake and translocation in leaves. Nitrifying bacteria was shown to be a useful tool to biomonitor soil quality. These results proved the suitability of the giant reed for assisted-phytoremedation with the use of compost fertilisation and T. harzianum.