Lettuce Production Research Articles

Response of Lettuce (Lactuca sativa L.) To Aquaculture Wastewater Treatment

The fish feed waste and litters are organic matter that can be a source of nutrients for plants. This study is aimed to determine the growth and production of lettuce (Lactuca sativa L.) treated with wastewater from hard-lipped barb culture of several population densities. The research was carried out from April through June of 2020 at the greenhouse of the Agrotechnology Study Program, Faculty of Agriculture, Djuanda University, Bogor, Indonesia. The controlled study used a randomized block design with one factor, wastewater from fish population density of 10, 20 and 30 per 21 L of water, and AB Mix as a control. Plants treated with the AB Mix were significantly superior to those plants treated with the hard-lipped barb farming wastewater, demonstrated by taller plants, more and larger leaves, larger stem diameter and leaf area, longer roots, greater fresh and dry weight, as well as a higher leaf nitrate content. The aquaculture wastewater at the tested fish density in this study did not support optimal growth of lettuce, so lettuce production is still very low compared to those grown with the AB mix.

Multi-objective optimal regulation model and system based on whole plant photosynthesis and light use efficiency of lettuce

Lettuce growth and light energy consumption in a plant factory with artificial lighting (PFAL) were studied, and whole plant photosynthetic rate (ACO2) and light use efficiency (LUE) data were obtained on different days after planting (DAP) under different photosynthetic photon flux densities (PPFDs). Genetic algorithm‐support vector regression (GA-SVR) was used to construct the ACO2 and LUE prediction models. The coefficient of determination (R2) between the predicted and measured values of the ACO2 model was 0.97 and the root mean square error (RMSE) was 0.42 μmol·mol−1·plant−1·min−1, and R2 between the predicted and measured values of the LUE model was 0.97 and RMSE was 0.36%. The ACO2 and LUE prediction models were used as the objective functions, and multi-objective search was performed by the non-dominated sorting genetic algorithm II (NSGA-II) and the distance-based knee point detection method were used to obtained the optimal equilibrium solution for different DAPs. The optimal equilibrium solutions were used as the basis to establish the light regulation model based on lettuce DAP with R2 of 0.99. To validate the effect of model regulation, a lettuce light regulation system was built using an artificial climate chamber for a 30-day system validation. The results showed that compared with the traditional quantitative light supplementation method, the dry matter of model regulation significantly increased by 39.23% and 29.48% compared with quantitative PPFD150 (μmol·m−2·s−1) and PPFD200 (μmol·m−2·s−1). Model regulation increased the number of total light quanta consumed by 1.39% over PPFD150 and decreased by 23.96% over PPFD200; however, plant productivity increased by 35.35% and 33.14%, respectively. Model regulation significantly reduced the number of light quanta consumed per unit mass of lettuce production by 24.35% for PPFD150 and 41.54% for PPFD200, and LUE of light-emitting diode energy into dry matter was significantly increased by 33.49% and 75.09%. Therefore, the light regulation model based on multi-objective optimization in this study could improve crop yield and increase LUE.

Optimization of an Indoor DWC Hydroponic Lettuce Production System to Generate a Low N and P Content Wastewater

Hydroponic production raises economic and environmental issues related to the treatment, recovery or disposal of hydroponic wastewater, which can be rich in eutrophication-related nutrients, nitrogen (N) and phosphorus (P). Little focus has been put on the influence of the growth conditions on the N and P content in hydroponic wastewater, which is of uttermost importance when it is intended to reuse the wastewater for irrigation or other purposes with reduced impact on the environment. This study aimed to optimize an indoor non-recirculating deep-water culture (DWC) hydroponic system for lettuce (Lactuca sativa L. var. crispa) production, in terms of daily light integral (DLI) and volume of nutrient solution (NS) per plant, to maximize both the biomass production and the N and P removal, allowing for the wastewater to meet the criteria established for reusing in irrigation and minimizing the eutrophication impacts. A small-scale DWC hydroponic system with a fluorescent light fixture was built to study lettuce growth indoors for 35 days after transplanting (DAT). A first experiment was conducted under 14, 20 or 23 mol m−2 d−1 DLI and with 1.5 or 2 L of NS per plant. A pronounced inner leaf tip burn was observed, regardless of the volume of NS solution used, related to the unventilated conditions under high radiation. Total biomass was similar in all treatments and N and P removal was higher than 95% and 94%, respectively, at 35 DAT. Lettuces grown in 2 L of NS per plant exhibited higher average biomass. A second experiment was performed under 8, 10 or 12 mol m−2 d−1 DLI and with 2 or 3 L of NS per plant, making it possible to achieve healthy biomass at 35 DAT with higher water and light-use efficiency when compared to the first experiment. A DLI of 10 or 12 mol m−2 d−1 with 2 L of NS per plant and a DLI of 12 mol m−2 d−1 with 3 L of NS per plant made it possible to achieve both the best total biomass production and the highest N and P removal from water. Under those conditions, hydroponic wastewater complied with N and P criteria for reuse in irrigation, showing potential to be used as an alternative resource for agriculture and to minimize negative impacts on the environment.

Effect of Duration of LED Lighting on Growth, Photosynthesis and Respiration in Lettuce.

Parameters of illumination including the spectra, intensity, and photoperiod play an important role in the cultivation of plants under greenhouse conditions, especially for vegetables such as lettuce. We previously showed that illumination by a combination of red, blue, and white LEDs with a high red light intensity, was optimal for lettuce cultivation; however, the effect of the photoperiod on lettuce cultivation was not investigated. In the current work, we investigated the influence of photoperiod on production (total biomass and dry weight) and parameters of photosynthesis, respiration rate, and relative chlorophyll content in lettuce plants. A 16 h (light):8 h (dark) illumination regime was used as the control. In this work, we investigated the effect of photoperiod on total biomass and dry weight production in lettuce plants as well as on photosynthesis, respiration rate and chlorophyll content. A lighting regime 16:8 h (light:dark) was used as control. A shorter photoperiod (8 h) decreased total biomass and dry weight in lettuce, and this effect was related to the suppression of the linear electron flow caused by the decreasing content of chlorophylls and, therefore, light absorption. A longer photoperiod (24 h) increased the total biomass and dry weight, nevertheless an increase in photosynthetic processes, light absorption by leaves and chlorophyll content was not recorded, nor were differences in respiration rate, thus indicating that changes in photosynthesis and respiration are not necessary conditions for stimulating plant production. A simple model to predict plant production was also developed to address the question of whether increasing the duration of illumination stimulates plant production without inducing changes in photosynthesis and respiration. Our results indicate that increasing the duration of illumination can stimulate dry weight accumulation and that this effect can also be induced using the equal total light integrals for day (i.e., this stimulation can be also caused by increasing the light period while decreasing light intensity). Increasing the duration of illumination is therefore an effective approach to stimulating lettuce production under artificial lighting.

Enhancing yield of lettuce through irrigation and nitrogen management in a subtropical Inceptisol

Abstract To address the dearth of management of lettuce in the Indo-Gangetic plains, field experiment was conducted on a sandy loam Inceptisol for optimizing the irrigation, nitrogen requirement and economics of lettuce for three years. Four irrigation levels (conventional, I1 and irrigation at 0.6, 0.8, 1.0 irrigation water to cumulative pan evaporation (IW/CPE) ratio, as I2, I3 and I4) and three nitrogen management (100% recommended dose of N i.e., RDN as inorganic, N1; 50:50% RDN as inorganic: vermicompost, N2 and 100% RDN as vermicompost, N3) was laid out in thrice replicated split plot design. All the major physiological characteristics like plant height, number of leaves, average head diameter was improved with I4, N2 and their interaction (I4N2). Maximum average head yield (10.6 t ha−1) was obtained with I4 and I3, 10.5 t ha−1 for N2, while I4N2 yielded 11.3 t ha−1. Maximum water productivity (11.8 kg m−3) was obtained under I2N2. A strong non-linear relationship was detected between yield with irrigation water applied (). Higher soil moisture extraction (80.2%) in top 0–30 cm and lower (19.8%) for 30–45 cm depth and maximum leaf dry matter yield, nutrient concentrations and uptake was found with I4N2 and I3N2. The moderate deficit irrigation and optimum nutrient at I3N2 was found best for optimizing yield, higher water productivity, nitrogen economy and monetary returns of lettuce.

Influence of Day and Night Temperature and Radiation Intensity on Growth, Quality, and Economics of Indoor Green Butterhead and Red Oakleaf Lettuce Production

Lettuce (Lactuca sativa) is among the most consumed vegetables worldwide and is primarily field-grown; however, indoor agriculture enables year-round, precise production. Through precise manipulation of the mean daily temperature (MDT) and photosynthetic photon flux density (PPFD), crop color, morphology, and yield can be altered. Therefore, we quantified how MDT and PPFD interact and developed models predicting yield and economic viability. Eleven days after sowing, green butterhead lettuce ‘Rex’ and red oakleaf lettuce ‘Rouxaï RZ’ were transplanted into six deep-flow hydroponic tanks with day/night and MDTs of 22/15 °C (20 °C), 25/18 °C (23 °C), or 28/21 °C (26 °C), under light-emitting diodes providing a low or high PPFD of 150 or 300 µmol·m−2·s−1 for 17-h·d−1. As PPFD increased, shoot fresh mass (SFM) of ‘Rex’ increased by 29% (33.4 g). SFM of ‘Rouxaï RZ’ and shoot dry mass (SDM) of both cultivars was influenced by the interaction of MDT and PPFD. The greatest ‘Rouxaï RZ’ SFM (158.8 g) and SDM (6.42 g) were recorded at >20 °C MDT under the high PPFD; the lowest SFM (76.0 g) and SDM (3.17 g) occurred at 20 °C under the low PPFD. Similarly, ‘Rex’ SDM was greatest (7.36 g) and lowest (3.78 g) under the aforementioned MDTs and PPFDs. Increasing from the low to high PPFD increased tipburn incidence on ‘Rouxaï RZ’ from 0 to 25% and ‘Rex’ from 47 to 100%. ‘Rouxaï RZ’ had darker yellow-red foliage at lower MDTs under the high PPFD. A high MDT and low PPFD resulted in a lighter green. Finally, for the greatest SFM, while reducing energy costs as interpreted from the economic analysis, we recommend growing ‘Rex’ and ‘Rouxaï RZ’ under a PPFD of 150 and 300 µmol·m−2·s−1, respectively, at an MDT of 23 to 26 °C depending on the cost of temperature control.

Autumn Production of Romaine Lettuce on an Extensive Green Roof

Extensive green roofs provide a significant amount of potential available space to expand urban agriculture. Successful crop production in this type of growing system requires growers to overcome temperature extremes, as well as drought conditions and low fertility associated with a shallow and porous rooting substrate. Four cultivars of Romaine lettuce (Lactuca sativa) that included ‘Outredgeous’, 'Parris Island Cos', 'Rouge d'Hiver', and 'Rubens Baby', were grown to maturity in an 8 cm deep expanded lightweight clay substrate on an extensive green roof during the autumn production seasons of 2012 and 2013. Fast and slow release fertilizer regimes popular with growers and a no fertilizer control were provided along with supplemental water via drip irrigation as needed. Chlorophyll content, as measured by a SPAD meter, provided a useful indicator of crop plant vigor and overall plant productivity. Abnormally cold growing conditions during the critical maturation period in autumn 2013 resulted in lower yields compared to 2012. Results indicated that lettuce productivity was improved by the addition of fertilizers, with the fast release providing the greatest growth and productivity. These results demonstrate the feasibility of producing a nutritious and popular autumn crop on an extensive green roof suitable for local urban food systems. However, this research also highlights the vulnerabilities of this system to weather. Utility of green infrastructure for teaching urban agriculture and plant biology is also discussed.

Anaerobically Treated Leachate from a Composting Plant: Characterization and Evaluation as a Biofertilizer

Leachate from a composting plant was characterized and applied as a biofertilizer in lettuce crops. Characteristics of untreated (UE) and anaerobically treated (TE) leachate samples were compared. The pH of TE (8.2) increased in relation to the UE (5.2) due to an increase in ammonia nitrogen in TE (1197 mg L-1) compared to UE (859 mg L-1). Anaerobic treatment was efficient in the removal of organic matter from the leachate, evaluated by the decrease of dissolved organic carbon, biochemical oxygen demand, total organic carbon and total solids. K presented the highest concentration (1743 mg L-1) in TE, followed by Mg (135 mg L-1). Cd, Pb and Cr were present at low concentrations in the samples, 0.047, 0.206 and 0.081 mg L-1, respectively. Salmonella, thermotolerant coliforms and viable helminth eggs were not present in TE, which was applied as a biofertilizer in a lettuce crop and compared to mineral fertilization based on fresh matter and dry matter production. Lettuce production using TE was statistically equivalent to mineral fertilization. Toxic metals were not detected in the lettuce shoots. It was concluded that the anaerobically treated leachate from the composting company has the potential to be used as a biofertilizer.

Effect of the low light intensity and ultraviolet radiation on the productivity of Karmesi lettuce

Plants of the red - leaved form of Karmezi lettuce varietie was grown at three irradiation levels of 80.60 and 25 mmol m-2 • s-1 with subsequent transfer of part of the plants To a high level of illumination with additional ultraviolet light. The production process, gas exchange and accumulation of anthocyanins were studied. It was shown that ultraviolet and high irradiation (80 mmol m-2 • s-1) stimulate the formation of anthocyanins in the lettuce plants.

Prevention of Phytotoxic Effects of Regenerative In Situ Electrochemical Hypochlorination in Recirculating Hydroponic Systems

Recirculating nutrient solutions were treated using dimensionally stable anode (DSA)-based regenerative in situ electrochemical hypochlorination (RisEHc) in a deep water culture hydroponic lettuce (Lactuca sativa) production system. Phytotoxic effects were noted and attributed to the formation of chloramines in treated nutrient solutions containing ammonium. The presence of chloramines resulted in a decrease in overhead biomass by 53% using 2.27 mA/cm2 and 83% with 4.55 mA/cm2. Adding ultraviolet light as a tertiary treatment stage allowed the photodecomposition of chloramines, which prevented phytotoxicity in crops and caused no significant differences in growth between treatments. Furthermore, using a nitrate-based fertilizer also served to prevent phytotoxic effects in crops and showed no significant differences in growth between the control and 4.55 mA/cm2. In addition, it was found that the electrochemical flow cell (EFC) treatment resulted in a 13% increase in shoot biomass using 2.27 mA/cm2. The study demonstrated that phytotoxic effects can be prevented with the use of regenerative in situ hypochlorination through proper management and monitoring techniques in recirculating hydroponic systems.

Compostagem de resíduos vegetais frescos e sua aplicação no cultivo de alface

ABSTRACT A considerable part of fresh plant-based food has been discarded as waste, although it could be used to make organic compost for growing plants, retaining nutrient that would be discarded without any control in the environment. The aim of this study was to produce an organic compost using fresh vegetable food discarded from restaurants and mowed grass and to evaluate it for production of lettuce. The compost was produced and mixed with the commercial substrate Tropstrato HT Hortaliças® to occupy 0, 5, 10, 15, 20 or 25% of the volume of the mixture, which was used to grow Imperial and Imperial Roxa cultivars in the first experiment, and Camila and Red Star lettuce cultivars in the second one. The experiments were conducted under protected environment, organized in a 6x2 factorial scheme, following completely randomized design with three replicates. Chemical analyses of the substrate and compost and measurements of plant size and mass were carried out. The addition of compost caused an increase in all measurements of the plant traits, with the maximum estimated increase ranging from 1.7 to 9.0 times that estimated for the absence of compost in the plant growth substrate. Maximum estimated values for size and mass were observed with compost concentrations ranging from 20.1 to 26.7% of the mixture volume. The production of organic compost and its mixture with a commercial substrate proved to be an alternative for lettuce production, giving a better destination to the organic residues and promoting a reduction in the use of industrial inputs.

HYDROPONIC LETTUCE (Lactuca sativa L. var. Lalique) PRODUCTION USING COMMERCIALLY AVAILABLE NUTRIENT SOLUTIONS

This study was carried out to assess commercially available nutrient solutions (Yamasaki, MaterBlend, Snap, Nutrihydro, and Hydroplus) in hydroponic lettuce production in comparison to organic fertilizers (Biovoltin) with water as a negative control. The crop experiment was conducted at the Institute of Agriculture, Camiguin Polytechnic State College-Catarman Campus, Tangaro, Catarman, Camiguin, from January 25, 2022, until March 10, 2022. The study was laid in a Randomized Complete Block Design with seven (7) treatments and three (3) replications at eight plants per treatment. Results of the study showed that considering horticultural growth and root characteristics, lettuce grown on Masterblend produced taller plants, longer leaf blades, and wider canopy, SNAP exhibited broader leaves, and Yamasaki with the greater number of leaves, longer roots, higher root volume, root fresh and total fresh weight while all treatment exhibited a 100% survival rate. In terms of yield, Masterblend had the higher fresh head weight per plant, the weight of marketable head per box, and total yield, Yamasaki, Masterblend, SNAP, and Hydroplus had a higher number of marketable yields, and Hydro plus had a higher harvest index. SNAP was considered best overall in terms of sensory quality attributes and marketability. Using the SNAP solution resulted in higher net return, net profit margin, and return on investment, followed by Masterblend, Hydroplus, and Yamasaki. It can be concluded that using commercially available nutrient solutions affects the growth and yield of lettuce in a hydroponic production system. However, its potential used should be further tested for verification under different growing seasons to elicit substantial conclusions.

Coberturas vegetais de solo no plantio direto de alface crespa

ABSTRACT Plant soil covers bring many benefits to the soil, like physical, chemical and biological quality. It may behave differently if kept on the ground or if incorporated. The objective of this research was to evaluate the effect of cover crops under no-tillage and conventional tillage systems on curly lettuce production. The treatments were in a split plot: three plant coverings in the plot [lupines, black oats, 70% lupines + 30% black oats (consortium)] and in the subplots two cropping systems [no-tillage and conventional tillage (plowing and harrowing)]. The consortium of black oat + lupine in conventional planting produced more than the other treatments and lettuce yield of 69.4 t/ha. The no-tillage in the present study is in its third economic crop cycle and possibly has not yet acquired all the benefits in the soil profile.

Technical feasibility of the use of sludge from the water treatment plant in lettuce production

The sludge generated in water treatment plants (WTP sludge), despite having physicochemical characteristics with agricultural potential, is a solid waste discarded in landfills. This research aimed to: 1) evaluate the technical feasibility of WTP sludge in substitution of commercial substrates in the production of lettuce seedlings; 2) to evaluate the yield commercial, in the municipality of Arapiraca, semiarid region of the state of Alagoas - Brazil. The research was carried out in two stages: 1) seedling production in greenhouse in 4 x 4 x 5 factorial arrangement, with four sludge doses (0, 20, 40 and 60%), four commercial substrates (Pindstrup®, Vida Verde®, Bioplant 434® and Bioplant 401®) and five cultivars (Veneranda, Camila, Elba, ‘Vitória Verdinha’ and Diva); 2) seedlings produced at field level were used in 3 x 3 x 5 factorial arrangement, in which Pindstrup treatments and 60% sludge dose were excluded, as they did not promote seedling emergence. In the 1st experiment, it was observed linear reduction of seedling quality index with the addition of sludge. In the 2nd experiment, the average yield was 5.4 Mg ha-1, in which 20% sludge dose promoted the highest values, being recommended for lettuce production in the semiarid region of Alagoas.

Pre-harvest Nitrogen Limitation and Continuous Lighting Improve the Quality and Flavor of Lettuce (Lactuca sativa L.) under Hydroponic Conditions in Greenhouse.

Short-term nitrogen limitation and continuous lighting (red/blue = 3:1) were applied individually and in combination to butterhead and red oak leaf lettuce for 1, 2, or 3 days before harvest to assess their effects on improving the nutritional value and sweet taste and reducing nitrate content and bitterness of lettuce. The results suggested that a 3-day nitrogen limitation combined with continuous lighting reduced the lettuce content of nitrate and sesquiterpene lactones and improved the quantities of soluble sugar, soluble protein, anthocyanins, and phenolic compounds without reducing the fresh weight of lettuce. In addition, in vitro simulated digestion results suggested that the 3-day nitrogen limitation combined with continuous lighting significantly improved the sweetness and reduced the bitterness of lettuce compared to the control. In conclusion, nitrogen limitation combined with continuous lighting for 3 days before harvest effectively enhanced the quality and taste of lettuce, showing great potential for its use in hydroponic lettuce production.

Aqua-Ento-Ponics: Effect of Insect Meal on the Development of Sea Bass, Dicentrarchus labrax, in Co-Culture with Lettuce

The aim of this study is to investigate the effect of 10 and 20% replacement of fishmeal (FM dietary group) with the superworm Zophobas morio larvae meal (ZM10 and ZM20 dietary groups) on the growth performance of sea bass (Dicentrarchus labrax) and lettuce plants (Lactuca sativa) reared in aquaponics. Ninety juvenile sea bass with an average body weight of 21.55 g/individual were placed in aquaponic fish tanks, together with 24 lettuce plants with an average initial height of 8.90 cm/plant and an average number of leaves of 5.75/plant over a 45-day trial period. At the end of that period, all feeding groups exhibited high survival. In fact, ΖΜ10 and ZM20 groups showed similar fish weight gain and specific growth rate (SGR) (p > 0.05), but significantly lower SGR (p < 0.05) than the FM group. Nevertheless, final fish body weight and length were similar (p > 0.05) for all feeding groups. No plant mortality was observed during the 45-day study period. All three aquaponic systems resulted in similar leaf fresh weight, as well as fresh and dry aerial biomass. At the end of the experimental period, plants in the third system showed higher fresh leaf weight, total weight of fresh leaves, total dry aerial biomass, and total produced biomass compared to the other two systems. The results of the present study show that fish fed with the ZM10 diet had higher weight gain (WG) than fish fed with the ZM20 diet, while the SGRs for ZM10 and ZM20 were similar. Both ZM10 and ZM20 diets result in efficient lettuce production. This study also provides data that enlighten the feasibility of integrating insect meals as fish feeds for aquaponics which helps towards the development of an ento-aquaponic approach.

Determination of Optimum Rate of Nitrogen, Phosphorus, Potassium and Boron for Leaf and Seed Yield of Lettuce

The experiment was conducted at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, during October 2012 to May 2013 to determine the optimum rate of nutrients for sustainable lettuce production. Nineteen treatment combinations were considered with five levels of each elements such as nitrogen viz. 0, 50, 100, 150 and 200 kg ha-1; phosphorus viz. 0, 25, 50, 75 and 100 kg ha-1; potassium viz. 0, 50, 100, 150 and 200 kg ha- 1; boron viz. 0, 0.5, 1.0, 1.5 and 2.0 kg ha-1. Results revealed that treatment T3 (N100P50K100B1.0) showed the maximum leaf and seed yield of lettuce. Fertilizer doses under T3 also showed the highest gross margin Tk. 305825 and Tk. 2816675 ha-1 and BCR 7.50 and 70.0 for leaf and seed yield, respectively. But, from regression analysis optimum doses of nitrogen, phosphorus, potassium and boron for maximum leaf yield (23.11 ton ha-1) and seed yield (571.5 kg ha-1) were N143P74K95B1.26 and N136.4P67.8K118.0B1.0, respectively that could be recommended as the best combination of nutrients for achieving higher leaf and seed yield of lettuce.
 Bangladesh J. Agril. Res. 45(4): 455-471, December 2020

Modeling resource consumption and carbon emissions associated with lettuce production in plant factories

Plant factories (PFs), multi-layer production in opaque warehouses, are novel production systems with many potential benefits and some key impediments, notably, energy consumption. The economic viability and environmental footprint of PF facilities depend on energy consumption associated with lighting, heating, ventilation, and cooling to the production space. Light and energy-system modeling can inform designers and investors about the energy requirements and economics related to a proposed or existing facility. Previous models have focused on comparing energy consumption between PFs and greenhouses (GH) in a limited number of production scenarios. There is little information regarding water consumption and carbon emissions at PF facilities and how energy conservation measures (ECMs) may impact water use efficiency, upstream emissions and purchased carbon-dioxide. The objective of this study is to model energy and water use in PFs growing lettuce in five U.S. locations (New York, NY, Los Angeles, CA, Seattle, WA, Chicago, IL, and Atlanta, GA) with three types of ECMs: installing lighting fixtures with high photon efficacy, introducing outdoor air for cooling through use of an air-side economizer, and maintaining elevated levels of carbon dioxide in the crop production space to enhance photosynthesis. Building energy modeling (BEM) software EnergyPlus was employed to simulate environmental conditions and associated energy consumption. Energy consumption ranges from 6.2 to 12.0 kWh kg−1 fresh weight of lettuce produced depending on design and operational choices. Water consumption for irrigation and production operations ranges between 2.0- and 9.8-L of water per kg (FW) lettuce produced. Beyond operating parameters, the primary emissions associated with energy consumption at the facility varies widely due to the energy mix of each location's grid, ultimately ranging between 0.6 and 3.9 kg carbon dioxide equivalent emissions per kg (FW) lettuce produced. We conclude that locating PFs in areas with a cleaner grid and employing these ECMs can reduce the energy consumption associated with growing lettuce indoors, though there are important tradeoffs to consider between water, energy, and supplemental carbon-dioxide in design.

Cultivo de alface sob diferentes doses de organomineral como fonte de fósforo e micronutrientes

ABSTRACT The use of organomineral fertilizers (OF) in the cultivation of vegetables has been considered a promising technology to provide nutrients gradually. The OFs can reduce the phosphorous (P) soil adsorption and leaching of nitrogen and potassium with the supply of some micronutrients. This study aimed to evaluate doses of OF as a source of P and micronutrients (boron and zinc) for curly lettuce cultivation. Five OF doses were evaluated: T1 = 0% (no P2O5 fertilization); T2 = 50% (75 mg/dm3 of P2O5); T3 = 100% (150 mg/dm3 of P2O5); T4 = 150% (225 mg/dm3 of P2O5); T5 = 200% (300 mg/dm3 of P2O5) of the lettuce recommended fertilization; T6 = 100% mineral fertilizer (MF) (150 mg/dm3 of P2O5). The fresh (FM) and dry mass (DM) of the lettuce shoot (aerial part), the soil nutrient level, and the plant nutritional status at harvest were evaluated. We observed that (i) the doses of 225 and 300 mg/dm3 of P2O5 via OF provided the same availability of P in the soil as the dose of 150 mg/dm3 of P2O5 of MF; (ii) the doses of 225 and 300 mg/dm3 of P2O5 of OF provided higher levels of soil boron and zinc compared to other treatments and (iii) the MF fertilization was more efficient than that of OF in the production of curly lettuce in a protected environment.

Preliminary results on N2O emission factor calculation in hydroponic struvite fertilization of lettuce production

ISHS XXXI International Horticultural Congress (IHC2022): International Symposium on Urban Horticulture for Sustainable Food Security (UrbanFood2022) Preliminary results on N2O emission factor calculation in hydroponic struvite fertilization of lettuce production