Contribution of cauliflower residues to N nutrition of subsequent lettuce crops grown in rotation in an Italian Alpine environment

Up to 75% of nitrogen (N) taken up during cauliflowers production is allocated to leaves, which are left as crop residues after harvest. The inclusion of cauliflower, cultivated alone or intercropped with legumes, in rotation schemes, is a promising tool to optimize N availability to subsequent crops. This original study assessed, for the first time in South Tyrol, Italy, the effect of removal or soil incorporation of cauliflower and clover residues on the growth and N uptake of subsequent lettuce. In 2015, cauliflower was sole-cropped or intercropped with clover, under different N regimes (N0, N1, N2, N3 = 0, 75, 150, 300 kg N ha−1). Cauliflower and clover residues were either removed or incorporated in the soil in 2016. The effects of the residual fertility left by the N fertilizer, the two cropping systems, and the crop residues were assessed on the yield and N uptake of two subsequent lettuce crops. Isotopic 15Nlabeled cauliflower residues were additionally used to quantify the N contribution of cauliflower residues to lettuce growth. During the first lettuce crop, residues incorporation was the only factor increasing lettuce yields (+41%) and N uptake (+58%). The residual effect of N1 and N2 rates increased the lettuce N uptake when clover residues were incorporated. During the second lettuce crop, residues incorporation increased lettuce yields (+26%) and N uptake (+44%). On average, 64% and 35% of the lettuce N amounts, in the first and second cycles, respectively, derived from cauliflower residues, and accounted for 38% of the total N contained in cauliflower residues (214 kg N ha−1). Results from this experiment, uncommon for the examined species, demonstrate that incorporation of cauliflower and clover residues provides an excellent source of N for lettuce. Incorporating residues of the preceding cauliflower crop, alone or intercropped with clover, before establishing the lettuce crop, substantially reduce the N fertilization needs of subsequent lettuce crops

Dieci orti brevi. Storie di piante, uomini e altri animali

10 Orti Brevi. Storie di piante uomini e altri animali. Dieci racconti sulla storia di ortaggi, scritti nell'occasione dell'evento 10 orti brevi, nell'ambito dell’evento nazionale “Che Gusto” di Repubblica-Gusto, che si è svolto a Bologna nell’autunno del 2023

How Can Innovation in Urban Agriculture Contribute to Sustainability? A Characterization and Evaluation Study from Five Western European Cities

Compared to rural agriculture, urban agriculture (UA) has some distinct features (e.g., the limited land access, alternative growing media, unique legal environments or the non-production-related missions) that encourage the development of new practices, i.e., \u201cnovelties\u201d or \u201cinnovations\u201d. This paper aims to (1) identify the \u201ctriggers\u201d for novelty production in UA; (2) characterize the different kinds of novelties applied in UA; (3) evaluate the \u201cinnovativeness\u201d of those social, environmental and economic novelties; and, (4) estimate the links between novelties and sustainability. The study was based on the evaluation of 11 case studies in four Western European countries (Italy, Germany, France and Spain). The results show that the trigger and origin of new activities can often be traced back to specific problems that initiators were intended to address or solve. In total, we found 147 novelties produced in the 11 case studies. More novelties are produced in the environmental and social dimensions of sustainability than in the economic. In most cases, external stakeholders played an important role in supporting the projects. The analysis further suggests that innovativeness enhances the overall sustainability in urban agriculture projects

Morphological and Physiological Plant Responses to Drought Stress in Thymus citriodorus

Water availability is considered as a determinant factor that affects plant growth. The commercial medicinal values of an aromatic plant rely on the presence of secondary metabolites that are affected under water shortage. Two-year-old Thymus citriodorus plants were subjected to different polyethylene glycol (PEG-6000) levels (0, 2%, and 4%) under greenhouse condition. PEG treatment lasted for 15 days. Thyme plant showed a morphological drought avoidance mechanism by maintaining the root system development through shoot fresh weight reduction resulting in promoted root absorption capacity and sustained plant growth. Moreover, stressed plants were able to maintain water use efficiency and root: shoot ratio suggesting a strong relation between root water uptake and water use saving strategies. Furthermore, thyme plants reduced tissue dehydration through stomatal closure and improved root water uptake. Content of volatile oil constituents of geraniol and diisobutyl phthalate increased upon drought stress while pseudophytol was reduced. Unexpectedly, thymol was not reported as a main oil element under either control or mild stress condition, while it was increased upon high drought stress in measure of 4.4%. Finally, carvacrol significantly accumulated under high drought stress (+31.7%) as compared to control plants

Supplemental LED Lighting Effectively Enhances the Yield and Quality of Greenhouse Truss Tomato Production: Results of a Meta-Analysis

Intensive growing systems used for greenhouse tomato production, together with light interception by cladding materials or other devices, may induce intracanopy mutual shading and create suboptimal environmental conditions for plant growth. There are a large number of published peer-reviewed studies assessing the effects of supplemental light-emitting diode (LED) lighting on improving light distribution in plant canopies, increasing crop yields and producing qualitative traits. However, the research results are often contradictory, as the lighting parameters (e.g., photoperiod, intensity, and quality) and environmental conditions vary among conducted experiments. This research presents a global overview of supplemental LED lighting applications for greenhouse tomato production deepened by a meta-analysis aimed at answering the following research question: does supplemental LED lighting enhance the yield and qualitative traits of greenhouse truss tomato production? The meta-analysis was based on the differences among independent groups by comparing a control value (featuring either background solar light or solar + HPS light) with a treatment value (solar + supplemental LED light or solar + HPS + supplemental LED light, respectively) and included 31 published papers and 100 total observations. The meta-analysis results revealed the statistically significant positive effects (p-value < 0.001) of supplemental LED lighting on enhancing the yield (+40%), soluble solid (+6%) and ascorbic acid (+11%) contents, leaf chlorophyll content (+31%), photosynthetic capacity (+50%), and leaf area (+9%) compared to the control conditions. In contrast, supplemental LED lighting did not show a statistically significant effect on the leaf stomatal conductance (p-value = 0.171). In conclusion, in addition to some partial inconsistencies among the considered studies, the present research enables us to assert that supplemental LED lighting ameliorates the quantitative and qualitative aspects of greenhouse tomato production

LED lighting for indoor cultivation of basil

Indoor cultivation systems are gaining importance worldwide, thanks to their greater efficiency in the use of resources (water, land and nutrients). The limiting factor for these systems is the illumination costs that are still high. In this context, LEDs (light emitting diodes) are gaining attention because of their ability to provide the required light spectra, and high electricity use efficiency. The goal of this study is to identify the role played by red:blue (R:B) ratio on the resource use efficiency of indoor basil cultivation, linking the light physiological response to changes in yield and nutritional properties. Basil plants were cultivated in growth chamber under 5 different R:B ratio LED lighting regimens (respectively, RB0.5, RB1, RB2, RB3, and RB4), using fluorescent lamps as control (CK1). For the six light treatments, a PPFD of 215 mol m-2 s-1 and a photoperiod of 16/8 light/dark per day were provided. Greater biomass production was associated with LEDs lighting as compared with fluorescent lamp, with best performances observed using RB≥2. Adoption of RB2 and RB3 improved also the plant’s capacity to transform resources, resulting in greatest water, land and energy use efficiency. Nutrient use efficiency was increased by using LED lights with a greater portion of blue light in the spectrum. Decreasing R:B ratio also increased leaf stomatal conductance. Plant grown under RB3 showed the best antioxidant properties in terms of flavonoid content and FRAP as compared to the other light treatments. From this study it can be concluded that a R:B ratio of 3 (RB3) provides optimal growing conditions for indoor cultivation of basil

Winter Greenhouse Tomato Cultivation: Matching Leaf Pruning and Supplementary Lighting for Improved Yield and Precocity

Solar radiation entering a high-wire tomato greenhouse is mostly intercepted by the top of the crop canopy, while the role of lower leaves diminishes with age, turning them into sink organs rather than sources. Accordingly, the defoliation of basal leaves is a widely applied agronomic practice in high-wire greenhouse cultivation management. However, the recent increase in the application of supplemental light emitting diode (LED) lighting for high-density tomato production may affect the role of basal leaves, promoting their source role for fruit development and growth. The present research aims to explore the application of supplementary LED lighting on Solanum lycopersicum cv. Siranzo in the Mediterranean area during the cold season in combination with two regimes of basal defoliation. The defoliation factors consisted of the early removal of the leaves (R) right under the developing truss before the fruit turning stage and a non-removal (NR) during the entire cultivation cycle. The lighting factors consisted of an artificial LED lighting treatment with red and blue diodes for 16 h d−1 (h 8-00) with an intensity of 180 µmol s−1 m−2 (RB) and a control cultivated under natural light only (CK). The results demonstrated a great effect of the supplemental LED light, which increased the total yield (+118%), favoring fruit setting (+46%) and faster ripening (+60%) regardless of defoliation regimes, although the increased energy prices hinder the economic viability of the technology. Concerning fruit quality, defoliation significantly reduced the soluble solid content, while it increased the acidity when combined with natural light

Supplemental LED lighting improves fruit growth and yield of tomato grown under the sub-optimal lighting condition of a building integrated rooftop greenhouse (i-RTG)

Unidad de excelencia María de Maeztu CEX2019-000940-MThe metabolism of a building can be connected to a rooftop greenhouse, exchanging energy, water and CO2 flows, therefore reducing emissions and recycling cultivation inputs. However, integrating a rooftop greenhouse onto a building requires the application of stringent safety codes (e.g., fire, seismic codes), to strengthen and secure the structure with safety elements such as thick steel pillars or fireproof covering materials. These elements can shade the vegetation or reduce solar radiation entering the rooftop greenhouse. Nevertheless, application of additional LED light can help to overcome this constraint. The present study evaluated supplemental LED light application in an integrated rooftop greenhouse (i-RTG) at the ICTA-UAB research institute, located in Barcelona (Spain), for tomato cultivation (Solanum lycopersicum cv. Siranzo). The experiment explored the effects of three LED lighting treatments and a control cultivated under natural light only (CK). Applied treatments, added to natural sunlight, were: red and blue (RB), red and blue + far-red (FR) for the whole day, and red and blue + far-red at the end-of-day (EOD), each for 16 h d−1 (8 a.m.-12 a.m.) with an intensity of 170 µmol m−2 s−1. The results indicate that LED light increased the overall yield by 17% compared with CK plants. In particular, CK tomatoes were 9.3% lighter and 7.2% fewer as compared with tomatoes grown under LED treatments. Fruit ripening was also affected, with an increase of 35% red proximal fruit in LED-treated plants. In conclusion, LED light seems to positively affect the development and growth of tomatoes in building integrated agriculture in the Mediterranean area