Weight Of Lettuce Research Articles

Combined Effects of Magnetized Irrigation and Water Source on Italian Lettuce (Lactuca sativa L. var. ramosa Hort.) Growth and Gene Expression

Agricultural water scarcity has become a global issue. Optimizing irrigation water quality and effectively utilizing non-conventional water resources are essential strategies to alleviate pressure on agricultural water use and achieve sustainable development. This study employed Italian lettuce as the test crop to explore the effects of magnetization treatment (M) at a magnetic field strength of 0.2 T and various irrigation water sources (T) on its growth. The following six treatments were established: fresh water irrigation (M0T1), recycled water irrigation (M0T2), saline water irrigation (M0T3), magnetized fresh water irrigation (M1T1), magnetized recycled water irrigation (M1T2), and magnetized saline water irrigation (M1T3). The results showed that the magnetization treatment increased the electrical conductivity (EC), power of hydrogen (pH), and dissolved oxygen (DO) of the three water sources compared to the non-magnetized treatment. Furthermore, magnetized irrigation with fresh water, recycled water, and saline water increased the contents of nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) in lettuce. It also led to increases in the contents of soluble proteins (by 9.27% to 22.25%), soluble sugars (by 13.45% to 20.50%), and vitamin C (VitC) (by 4.18% to 19.33%) in lettuce. Additionally, it enhanced the above-ground fresh weight of lettuce (by 9.36% to 8.81%) and water productivity (WPc) (by 5.85% to 10.40%), while reducing water consumption. Among these treatments, magnetized fresh water irrigation was the most effective in improving quality, fresh weight, and WPc, followed by magnetized recycled water. Gene expression analysis revealed that differentially expressed genes (DEGs) were primarily enriched in metabolic pathways such as the MAPK signaling pathway—plant, phytohormone signaling, and cysteine and methionine metabolism. In summary, magnetized irrigation significantly enhanced DO levels in irrigation water, along with the fresh weight, quality, and WPc of lettuce, demonstrating its effectiveness as an efficient method for agricultural irrigation.

Effect of Nutrient Solution pH on the Growth and Quality of Lactuca sativa Grown in a Static Hydroponic System

Lettuce is an easy-to-grow and nutrient-rich leafy vegetable. It grows well using a static hydroponic system, which saves space and is easy to maintain. However, understanding pH’s impact on lettuce growth in static hydroponic systems is limited. Hence, this study was conducted to determine the effect of pH nutrient solution on the growth performance and eating quality of lettuce grown in a static hydroponic system. Lettuce was grown in pH 5.2, 6.2, and 7.2 nutrient solutions. Its growth performance was collected weekly, including plant height, root length, number of leaves, leaf area, leaf chlorophyll content, total dry weight, and total moisture content. The harvested lettuce was analyzed for firmness, soluble solids concentration, titratable acidity, pH, and ascorbic acid content by the fourth week after transplanting. The plant height, root length, number of leaves, leaf area, and total dry weight of lettuce were affected by the interaction between nutrient solution pH and weeks after transplanting. By the third week after transplanting, lettuce grown in pH 6.2 was 11.12 and 18.67% taller than those grown in pH 7.2 and 5.2 nutrient solutions, respectively. By the fourth week after transplanting, the firmness of lettuce grown in pH 6.2 was significantly higher than those grown in pH 5.2 and 7.2 nutrient solutions by 2.34 and 7.32%, respectively. It is concluded that lettuce should be grown in a pH 6.2 nutrient solution when using a static hydroponic system.

The Selection of Lettuce Seedlings for Transplanting in a Plant Factory by a Non-Destructive Estimation of Leaf Area and Fresh Weight

Selecting uniform and healthy seedlings is important to ensure that a certain level of production can be reliably achieved in a plant factory. The objectives of this study were to investigate the potential of non-destructive image analysis for predicting the leaf area and shoot fresh weight of lettuce and to determine the feasibility of using a simple image analysis to select robust seedlings that can produce a uniform and dependable yield of lettuce in a plant factory. To vary the range of the leaf area and shoot fresh weight of lettuce seedlings, we applied two- and three-day irrigation intervals during the period of seedling production and calculated the projected canopy size (PCS) from the top-view images of the lettuce seedlings, although there were no significant growth differences between the irrigation regimes. A high correlation was identified between the PCS and shoot fresh weight for the lettuce seedlings during the period of seedling production, with a coefficient of determination exceeding 0.8. Therefore, the lettuce seedlings were classified into four grades (A–D) based on their PCS values calculated at transplanting. In the early stages of cultivation after transplanting, there were differences in the lettuce growth among the four grades; however, at the harvest (28 days after transplanting), there was no significant difference in the lettuce yield between grades A–C, with the exception of grade D. The lettuce seedlings in grades A–C exhibited the anticipated yield (150 g/plant) at the harvest time. In the correlation between the PCS and leaf area or the shoot fresh weight of lettuce during the cultivation period after transplanting and the entire cultivation period, the R2 values were higher than 0.9, confirming that PCS can be used to predict lettuce growth with greater accuracy. In conclusion, we demonstrated that the PCS calculation from the top-view images, a straightforward image analysis technique, can be employed to non-destructively and accurately predict lettuce leaf area and shoot fresh weight, and the seedlings with the potential to yield above a certain level after transplanting can be objectively and accurately selected based on PCS.

Destructive effect of UV-C light radiation on lettuce growth: risk assessment of long time exposure

Ultraviolet C (UV-C) light technology employs a particular wavelength within the ultraviolet spectrum to deactivate microorganisms, utilizing radiation as its method. UV-C light possesses germicidal properties, effectively disrupting the DNA of microorganisms such as bacteria, viruses and various pathogens, thereby impeding their ability to replicate and induce illness. Additionally, UV-C could enhance the production of phytochemicals and prevent contamination in agricultural applications. However, overexposure to UV-C can cause safety issues, especially for operators handling its utilization in germicidal or sterilization applications. This study investigated the destructive effects of UV-C light on the morphology and chlorophyll content of lettuces exposed to various durations, aiming to assess the risks associated with prolonged exposure. The results showed that prolonged UV-C exposure affects morphological and chlorophyll content changes. The most damaging effect on lettuce morphology and chlorophyll content was found in the 2 h of UV-C exposure treatment. In the 2 h of UV-C exposure treatment, lettuce length was reduced from 6.01 ± 0.80 cm on day 2 to 5.55 ± 0.78 cm on day 3. The lowest fresh weight of lettuce was also found at 2 h of UV-C exposure treatment (4.32 ± 0.94 gr). In addition, the lowest total lettuce stomata aperture was found in 2 h of UV-C treatment (41 units). Furthermore, on day 4, after 2 h of UV-C exposure treatments, the chlorophyll a, chlorophyll b and total chlorophyll content in lettuces were found to be 1.59 ± 0.02 mg g−1 FW, 0.93 ± 0.02 mg g−1 FW and 2.52 ± 0.04 mg g−1 FW, respectively. Therefore, the most destructive effect of UV-C was found during 2 h of UV-C exposure treatment. These findings indicate the dangers of long-term UV-C exposure to lettuce. Practically, this could also have a negative impact on humans. The knowledge gleaned from these findings is useful for safety issues in the industrial application of UV-C.

Supplementary Far-Red Light for Photosynthetic Active Radiation Differentially Influences the Photochemical Efficiency and Biomass Accumulation in Greenhouse-Grown Lettuce.

Adding far-red (FR, 700-800 nm) light to photosynthetic active radiation (400-700 nm) proved to be a possible approach to increasing plant biomass accumulation for lettuce production in indoor vertical farms with artificial lighting as a sole-source lighting. However, how FR light addition influences plant growth, development, and metabolic processes and the optimal value of FR photon flux density for greenhouse-grown lettuce under sunlight are still unclear. This work aims to quantify the value of supplementary FR light with different intensities on lettuce morphological and physiological characteristics in a greenhouse. Lettuce 'Dasusheng' (Lactuca sativa L.) was grown in a greenhouse under seven light treatments, including white plus red LEDs with FR photon flux density at 0, 10, 30, 50, 70, and 90 µmol m-2 s-1 (WR, WR + FR10, WR + FR30, WR + FR50, WR + FR70, and WR + FR90, respectively), and lettuce grown with sunlight only was marked as natural light (NL). FR light addition improved the electron transport flux per cross section and performance index (PIabs, PItotal) and decreased the changes in relative variable fluorescence of lettuce leaves compared to plants under NL. Specifically, the PIabs of lettuce leaves were 41%, 41%, 38%, 33%, 26%, and 25% lower under control than in plants under treatments WR + FR90, WR + FR70, WR + FR50, WR + FR30, WR + FR10, and WR, respectively. Leaf number, leaf area, and biomass accumulation of lettuce followed a quadratic function with increasing FR light intensity and were the highest under treatment WR + FR50. The shoot fresh weight and dry weight of lettuce were increased by 111% and 275%, respectively, under treatment WR + FR50 compared to NL. The contents of vitamin C, reducing sugar, total soluble sugar, and starch in lettuce showed a similar trend with biomass accumulation. In conclusion, with commonly used photosynthetic photon flux density (PPFD, 400-700 nm) around 200 μmol m-2 s-1, supplementary FR light intensity of 30~50 μmol m-2 s-1 was suggested to enhance the photochemistry efficiency, biomass accumulation, and carbohydrates' contents in greenhouse-grown lettuce.

Suitability of coconut bran and biochar as a composite substrate for lettuce cultivation in aquaponic systems

Growth substrates are essential for aquaponic systems and play an important role in vegetable growth and water quality. In this study, we explored an innovative combination of coconut bran and coconut shell biochar (CSB) as a composite growth substrate for lettuce cultivation in aquaponic systems. The study included the control (100 % coconut bran as the growth substrate) and treatment groups (T1–T5; containing 10 %, 20 %, 30 %, 40 %, and 50 % CSB as the growth substrate, respectively). The substrate properties; lettuce growth performance; and soil enzyme activity, nitrogen content, and abundance of microbial communities in the substrate were analyzed to determine the optimal substrate. Our findings indicated that CSB incorporation significantly altered the properties of the substrate, resulting in increased dry and bulk densities, pH, and water-holding capacity, and decreased electrical conductivity, water-absorption capacity, and porosity. Furthermore, the fresh weight of lettuce was notably increased in the treatment groups. The activities of fluorescein diacetate hydrolase, urease, nitrate reductase, and hydroxylamine reductase initially increased and further decreased, reaching the maximum in the T3 group. Conversely, the activity of nitrite reductase and contents of available nitrogen, nitrate-nitrogen, and ammonium-nitrogen in the substrates initially decreased and further increased, with the minimum values observed in the T3 group. The microbial sequencing results indicated that CSB incorporation significantly increased the microbial diversity and relative abundance of microorganisms associated with nitrogen transformation. Moreover, 30 % CSB incorporation exhibited the greatest effect on lettuce growth, with a 34.5 % and 31.6 % increase in fresh weight compared to the control during the growth and harvest periods, respectively. This study indicated the enormous potential of biochar in the research and development of green technologies for substrate amendment in aquaponic systems.

Effects of Applying Biochar on Soil Cadmium Immobilisation and Cadmium Pollution Control in Lettuce (Lactuca sativa L.)

In order to analyse the impact of biochar in terms of reducing the bioavailability of cadmium (Cd) in soil, a study was conducted on the solidification effect of biochar on soil cadmium and its resistance to cadmium contamination in lettuce. In this study, soil which was contaminated with 10 mg/kg cadmium was used as the substrate; corn, rice, and wheat straw biochar were used as solidification and amendment materials; and lettuce (Lactuca sativa L. cv. Grand Rapids) was used as the test plant. The morphological characteristics of the biochar, soil pH, electrical conductivity, cation exchange capacity, and soil-available Cd, as well as lettuce plant height, fresh weight, and leaf Cd content, were measured and analysed. The results showed that all three types of biochar possessed distinct porous structures and functional groups such as hydroxyl, ether, and carbonyl groups. Increases in soil pH, electrical conductivity (EC), cation exchange capacity (CEC), lettuce plant height, and fresh weight were effectively promoted. Additionally, a significant reduction in the available Cd content in the soil and Cd content in lettuce leaves was observed, with the inhibitory effect becoming more pronounced as the biochar application rate increased. When 5% corn straw biochar was added (1 kg of substrate with 50 g of biochar), the best inhibitory effect on Cd contamination was observed, with a cadmium content of 4.63 mg/kg in lettuce leaves. The available Cd in the soil and the Cd content in lettuce leaves decreased by 32.00% and 49.78%, respectively, compared to the CK group (without biochar treatment). Additionally, the plant height and fresh weight of lettuce increased by 25.56% and 31.31%, respectively, compared to the CK group. This indicated that the application of straw biochar can stabilise soil Cd, reduce the availability of Cd in the soil, inhibit the transfer of Cd into lettuce, promote the growth of lettuce, and lower the ecological environmental risk of Cd. These research results can provide a theoretical basis and scientific guidance for the remediation of soil Cd contamination and the safe production of lettuce.

Plasticulture film coextruded with essential oils: sustainable protection of salad crops

ABSTRACT Plasticulture has revolutionised Farming production. In salad cultivation, the snail is the main pest that can cause significant economic losses. The present study focuses on the design of a new industrial mulching material co-extruded separately with three essential oils: cade, turmeric and cumin oil. Experimental tests carried out on a pilot system confirmed the repellent effect against this mollusc and the protection of lettuce weight loss by about 30%. Adhesion tests by Escherichia coli and Pseudomonas aeruginosa demonstrate anti-adhesion properties of 80% when bioactive oils are incorporated into the industrial formulation of the plastic film. Application of the predictive theoretical approach confirms that the adhesion scores cannot be explained by the total adhesion energy and total hydrophobicity energy. This proves that these effects are the result of bioactive activity. This research work offers an innovative, practical and ecologically responsible alternative to protect lettuce crops against nuisances and pests.

Effects of Biochar on Growth and Pollutant Accumulation of Lettuce in Soil Co-contaminated with Tetracycline and Copper

Through lettuce potting experiments, the effects of different types of biochar (apple branch, corn straw, and modified sorghum straw biochar with phosphoric acid modification) on lettuce growth under tetracycline (TC) and copper (Cu) co-pollution were investigated. The results showed that compared with those under CK, the addition of biochar treatment significantly increased the plant height, root length, shoot fresh weight, and root fresh weight of lettuce (P < 0.05). The addition of different biochars significantly increased the nitrate nitrogen, chlorophyll, and soluble protein content in lettuce physiological indicators to varying degrees, while also significantly decreasing the levels of malondialdehyde, proline content, and catalase activity. The effects of biochar on lettuce physiological indicators were consistent during both the seedling and mature stages. Compared with those in CK, the addition of biochar resulted in varying degrees of reduction in the TC and Cu contents of both the aboveground and underground parts of lettuce. The aboveground TC and Cu levels decreased by 2.49%-92.32% and 12.79%-36.47%, respectively. The underground TC and Cu levels decreased by 12.53%-55.64% and 22.41%-42.29%, respectively. Correlation analysis showed that nitrate nitrogen, chlorophyll, and soluble protein content of lettuce were negatively correlated with TC content, whereas malondialdehyde, proline content, and catalase activity were positively correlated with TC content. The resistance genes of lettuce were positively correlated with TC content (P < 0.05). In general, modified biochar was found to be more effective in improving lettuce growth quality and reducing pollutant accumulation compared to unmodified biochar, with modified sorghum straw biochar showing the best remediation effect.

Effects of Supplemental Red and Far-Red Light at Different Growth Stages on the Growth and Nutritional Properties of Lettuce

The understanding of the supplementation scheme of red (R) and far-red (FR) light in the cultivation of leafy vegetables in plant factories with artificial lighting (PFALs) is still limited. This study investigated the effects of supplemental R and FR light at different plant growth stages on the morphology, growth characteristics, and nutritional properties of lettuce. Supplemented R + FR throughout the entire growth stages was beneficial for the growth of lettuce, for which the total fresh weight was increased by 53.76%, and it also enhanced the content of soluble sugars by 39.98% and vitamin E by 34.21%. The pre-supplementation of FR light followed by supplementation of R light at various growth stages not only increase the total fresh weight of lettuce by 26.10% but also ensured that most nutritional indices did not decrease, and it even increased the content of soluble sugars by 35.24% while decreasing the nitrate content by 31.52%. The scheme of pre-supplementation of R light followed by the supplementation of FR light promoted a more upright plant architecture in lettuce, which was advantageous for improving the cultivation density of lettuce in plant factories with artificial lighting, thereby enhancing the yield/m2. Moreover, it could increase the vitamin E content of lettuce. The growth and nutritional properties of lettuce exhibit significant effects under different supplementation methods of R and FR light. In PFALs, the selection of different light supplement schemes also requires a careful balance between yield and quality. From an energy-saving perspective, the pre-supplementation of FR light followed by supplementation of R light at various plant growth stages is beneficial for lettuce production in PFALs.

INFLUENCE OF DIFFERENT NUTRIENT SOURCES AND GENOTYPES ON THE CHEMICAL QUALITY AND YIELD OF LETTUCE

<p>The aim of this study was to examine the effect of different fertilizers on the yield and antioxidant capacity of two lettuce genotypes “Santoro RZ” and “Kiribati RZ”.</p> <p>Lettuce genotypes are fertilized with organic fertilizer (Slavol) and organic-inorganic NPK fertilizer (Fitofert hemisuper plus ) during the vegetation. The analyzed parameters were root length and head weight of lettuce, total phenols, and flavonoids, as well as antioxidant capacity. Lettuce genotypes “Santoro RZ” and “Kiribati RZ” fertilized with organic fertilization showed the highest content of total phenols (358.13 ± 1.30 mg RU/100 g of fresh sample), the total content of flavonoids (114.22 ± 0.3 mg RE/100 g of fresh sample) and antioxidant capacity (neutralization of DPHH radicals 58.72 ± 1.88%).</p> <p>The results revealed that the yield and antioxidant capacity of lettuce can be improved by using organic fertilizers.</p>

Enhancing lettuce yield via Cu/Fe-layered double hydroxide nanoparticles spraying

Layered double hydroxides (LDHs) have been widely used in the field of plant engineering, such as DNA/RNA transformation and enhancing plant disease resistance. However, few studies have examined the direct effects of LDHs on plants and their potential utility as nanofertilizers. In this study, the retention capacity of Cu/Fe-layered double hydroxide nanoparticles (CuFe-LDHs) was assessed by comparative experiments on vegetables. The results showed that the retention of CuFe-LDHs in leafy vegetables was high, such as lettuce. Phenotypic analysis revealed that the fresh and dry weights of lettuce leaves were both increased by spraying 10–100 μg/mL CuFe-LDHs. Using the optimal concentration of 10 μg/mL, we conducted further experiments to elucidate the mechanism of CuFe-LDHs promoting lettuce growth. It was found that the application of CuFe-LDHs had a significant effect on growth and induced physiological, transcriptomic, and metabolomic changes, including an increase in the chlorophyll b content, net photosynthetic rate, and intercellular carbon dioxide concentration, as well as modifications in gene expression patterns and metabolite profiles. This work provides compelling evidence that CuFe-LDHs can efficiently adsorb on the surface of lettuce leaves through hydrogen bonding, promote lettuce growth, mitigate the toxicity of heavy metal ions compared to their raw materials at the same concentration and offer a molecular-scale insight into the response of leafy vegetables to CuFe-LDHs.Graphical

Potential for Cultural Management of Lettuce Drop (Sclerotinia sclerotiorum) in High Tunnels Through Modification of Soil Moisture, Planting Date, and Cultivar

Lettuce is a high-value crop commonly grown in high tunnels. However, lettuce drop, caused by Sclerotinia sclerotiorum, can greatly impact lettuce production and profitability. Crop loss from S. sclerotiorum can be especially severe in high tunnels because of intensive cropping and limited options for non-host rotations. A study was conducted in a Kentucky high tunnel infested with S. sclerotiorum to determine if soil moisture, planting date, and host resistance can successfully manage lettuce drop. The experiment was arranged in a split-split plot design with soil moisture (high: 60 to 100%, low: 40 to 80% plant available water), planting date (early, mid, and late spring), and lettuce cultivar (Galactic, Harmony, Pirat, and Vulcan) being the main plot, subplot, and sub-subplot factors, respectively. In year one, lettuce drop incidence was significantly lower in the low soil moisture and early planting date, and significantly higher in Pirat lettuce. Marketable lettuce weight was significantly higher in the late planting and Vulcan treatments. In year two, lettuce drop incidence was significantly lower in the late planting and Galactic compared with all other treatments. There was no significant difference in lettuce drop incidence between the high and low soil moisture in year two. Harmony and Vulcan had significantly higher marketable weight compared with all cultivars. Planting date and lettuce cultivar had the strongest effect on lettuce drop incidence. Although mid-spring is considered the ideal time to plant lettuce in Kentucky, growers managing lettuce drop should consider planting earlier or later and selecting resistant cultivars appropriate for their markets.

Effect of planting media and poultry manure fertilizier on Growth And Weight OF Lettuce

Grelen lettluce is a vegeltable plalnt favolred by the peolple of Indolnesia whilch has nutrlitional, provitlamin A, potaslsium, and callcium (Suprliati & Herllina, 2014). Lettluce cultilvation reqluires nutrlients in the folrm of orglanic fertillizers to grlowth and devellopment. Poulltry manlure has the higlhest N, P and K contlent and is availlable molre quickly (Sari et al., 2016). Cocopeat is a planting medium that has very high absorption with a pH 5.0 – 6.8 and good for root growth (Fahmi, 2013). The purpose of this study was to obtain the right compositiovn of growing mediva with poltry manure for optimal growth and yield of green lettuce. The research at the Experimental Garden, Satu Nusa University of Lampung, from January to April 2023. The research method Factorial RAK, Factor 1 was poltry manure, P1 = 5 tons ha-1, P2 = 10 tons ha-1, P3 = 15 tons ha-1. Factor 2 is the composition of the planting,M1 = Soil 100%, M2 = Cocopeat : Soil = 50% : 50%, M3 = Cocopeat : Soil = 75% : 25% and M4 = Soil : Cocopeat = 25% : 75% . The data obtained from the observations were analyzed using the F test of analysis with a level of 5%. If the test results have a significant effect, then proceed with the BNJ with a level of 5%. The results giving a dose of poultry manure 15 tons ha-1 is the best and most optimal fertilizer dose for the growth of green lettuce plants.

Effect of different types and shapes of microplastics on the growth of lettuce

The presence of microplastics in agricultural soils has emerged as a significant environmental concern due to their persistent nature. Microplastics of different properties (i.e., types, shapes, size, concentration) are present in the environment, but the studies on the effect of microplastics having different properties are limited. Thus, this study investigated the effects of different microplastics (low-density polyethylene (LDPE) fragments, polyvinyl chloride (PVC) fragments, and LDPE fiber) in soil on the growth of lettuce (Lactuca sativa L.). Pot tests were carried out to study the effect of a range of microplastic concentrations and different shapes and types of microplastics in soil on the lettuce growth. The different growth parameters such as lettuce weight, lengths, and chlorophyll contents were measured and compared. The results showed that the adverse effects of the microplastics on the lettuce growth increased with increasing microplastic concentration. The effects of LDPE fragments and fibers on the root weights and the chlorophyll contents were microplastic shape-dependent. Also, the effects of LDPE fragments and PVC fragments on the shoot and root weights and the chlorophyll contents were microplastic type-dependent. Among the three microplastics studied, LDPE fragments tend to have greater effects on the lettuce growth than the other microplastics. Overall, the results show that the effects of microplastics on different growth parameters of lettuce can be shape- and/or type-dependent. The presence of microplastics having different properties make the understanding the effects of microplastics on plants difficult, and this necessitates further studies.

Utilizing co-composted biochar as a growing medium for buttercrunch lettuce

In this study, we explored the utilization of co-composted biochar (COMBI), the end product of co-composted poultry carcasses and biochar, as a growth medium for buttercrunch lettuce in a controlled environment. Despite the potential benefits that COMBI could provide, its use is currently limited, as reported in previous studies. The study's objective was to compare the performance of COMBI with various types of biochar with a comparison to a control group that used soil only. The results indicated that the application of COMBI treatment led to an increased water-holding capacity of the soil, ranging from 29% to 34%, which could help to mitigate drought stress and retain water-soluble nutrients under certain circumstances. However, there were no significant differences in stem diameter, dry shoot weight, or dry root weight of lettuce between the COMBI and control groups. While the use of COMBI did not result in increased crop yield, the study found that the application of wood-based biochar (WBC) and distiller's grain biochar (DGBC) in COMBI reduced the nitrate content in lettuce by 20.3–29.7% compared to the control group. Additionally, the application of COMBI treatment significantly lowered the Cu content of lettuce leaves. These findings suggested that the use of co-composted biochar as a growing media can have some benefits, particularly in terms of water-holding capacity and reduced nitrate and Cu content in lettuce leaves. However, the study highlights the need for continued research and development of this approach to ensure that it meets safety and quality standards and is a viable and sustainable option for crop production.

Allelopathic Effects of Conyza canadensis Water Extract on Seed Germination and Seedling Growth

In order to investigate the effects of allelo-pathic substances of Conyza canadensis on seed germination and seedlings, this study was designed to explore the allelopathic effects of Conyza canadensis water extract (CCE) on pakchoi, spinach and lettuce. Germination rates of three crops (pakcholi, spinach, and lettuce) during the seed germination, root length, seedling height, and fresh weight of two crops (pakcholi and lettuce) during the seedling were measured under different concentrations of CCE treatment (20, 40, 60, 80, 100 g/L). The allelopathic effect index was also calculated. The results showed that CCE had a varying degree of inhibitory effect on the germination rate of the seeds of the three crops. Spinach and lettuce have significant allelopathic effects from C. canadensis. At higher concentration of CCE, the germination rate of spinach and lettuce significantly decreased (P<0.01). After germination, the root length, seedling height, and fresh weight of the crop were measured, and the allelopathic effects were also calculated. It was found that the CCE had a significant inhibitory effect on root length, but it showed a promoting effect on seedling height and fresh weight of pakchoi, and CCE had a "low promotion-high inhibition" effect on seedling height and fresh weight of lettuce.

Yield and quality of lettuce (Lactuca sativa L.) depending on variety and type of nitrogen fertilizer

The aim of this research was to determine the effect of the application of different types of nitrogen fertilizer in five different varieties of lettuce on yield. The experiment was performed in the open field, in the spring cycle of growing during 2018 and 2019. The size of the base plot was 3 m2, and the trial was set up in a random block system. The trial covered the application of various forms of nitrogen fertilizers: ammonium sulphate, ammonium nitrate and urea. The applied nitrogen dose is 100 kg/ha (May 10th 2018 and May 8th 2019). Samples for the analysis of vitamin C and nitrate content, as well as yield determination, were carried out at the stage of the technological maturity of lettuce (60-62 days after seedling). The average weight of lettuce, depending on the variety, varied in the range of 211.3 g to 258.7 g. The use of ammonium nitrate resulted in the highest average weight of lettuce head (246.7 g), followed by the use of urea (238.9 g) and the lowest by the use of ammonium sulphate (221.0 g). The nutritional value of lettuce (vitamin C content) shows that depending on the applied form of nitrogen in the fertilizer, the highest content of vitamin C was determined by urea (10.86 mg/100 g), then ammonium sulphate (9.61 mg/100 g), and the lowest by ammonium nitrate (7.38mg/100g). The lower content of vitamin C was found in varieties of lettuce with red leaves compared to varieties with green leaves. The accumulation of nitrate in lettuce leaves directly depends on the variety and the applied fertilizer. The highest nitrate content was with ammonium nitrate (2355.6 mg/kg). The accumulation of nitrate in lettuce varieties with red leaves was higher compared to varieties with green leaves. Keywords: Lettuce, Nitrate, Vitamin C, Yield, Open field

Effect of NPK and Bacillus-coated NPK fertilizer on biomass, nutrient content in soil and nutrient uptake by lettuce

The Inoculation of beneficial soil microbes is an effective method for lowering doses of inorganic fertilizers. This study was aimed to observe and compare the effect of doses and formulas of Bacillus-coated NPK (BCN) and conventional NPK fertilizers on biomass, major macro-nutrient in soil and their uptake by shoots of lettuce (Lactuca sativa L.); as well as evaluate the potency of BCN for decreasing doses of NPK fertilizers. The greenhouse experiment was set up in a randomized block design with seven treatments and five replications. The treatments included one and a half doses of recommended NPK fertilizer and two BCN fertilizer formulas; control treatment was without any fertilizer. This experiment showed that NPK fertilizer had comparable effect with BCN on growth traits; but application of NPK and coated NPK had a potency to increase the fresh weight of lettuce up to 24-45% which was in line with the increase of shoot-to-roots ratio. The potassium (K) content in soil and their uptake in lettuce shoots depend on doses and type of NPK but Nitrogen (N) and Phosphorus (P) content in soil and in shoot were not determined by treatments. The results showed that the recommended NPK dose (200 kg/ha) for lettuce can be reduced up to 50%; moreover, 50% of BCN enabled to maintain the N, P and K uptake as well as the lettuce yield.

THE GROWTH AND YIELDS OF LETTUCE (LACTUCA SATIVA L.) ON A AQUAPONIC NFT (NUTRIENT FILM TECHNIQUE) SYSTEM WITH THREE DIFFERENT TYPES OF FISH

Introduction. Lettuce Cultivation (Lactuca sativa L.) with an aquaponic system can be used as an alternative to meet the food needs of the community in the midst of reduced agricultural land. The purpose of this research is to determine the types of fish that affect the growth and yield of lettuce (Lactuca sativa L.). The types of fish used in this research were tilapia, catfish and goldfish measuring 6-8 cm with a stocking density of 20 individuals. The observation variables included number of leaves, chlorophyll and wet weight of lettuce (Lactuca sativa L.). Methods. The research data were analyzed using One Way Anova Test and Duncan Multiple Range Test (DMRT). Result and Analysis. The results showed that goldfish gave optimal results on the number of leaves and wet weight of lettuce (Lactuca sativa L.), while catfish gave optimal results on the lettuce (Lactuca sativa L.) chlorophyll. Discussion. The different types of fish have a significant effect on the number of leaves, chlorophyll content and wet weight of lettuce plants (Lactuca sativa L.). the goldfish treatment (P3) gives optimal result on the number of leaves and wet weight of lettuce plants, while catfish treatment (P2) gives optimal results on chlorophyll of lettuce plants in the NFT aquaponic system.