Production Of Leafy Vegetables Research Articles

Assessment of the combined inputs of antimicrobials from top soil improvers and irrigation waters on green leafy vegetable fields

Sustainable food systems involve the recycling of biowaste and water. This study characterizes thirty-one top soil improvers of anthropogenic, animal, and green waste origin, along with eleven irrigation waters from rivers, channels, and civil wastewater treatment plants (cWWTPs) for the presence of antimicrobials. Liquid chromatography coupled with hybrid High-Resolution Mass Spectrometry (LC-HRMS/MS) was employed to identify forty-eight drugs belonging to the classes of sulfonamides (11), tetracyclines (7), fluoroquinolones (10), macrolides (12), amphenicols (3), pleuromutilins (2), diaminopyrimidines (1), rifamycins (1) and licosamides (1). Sludge from cWWTPs, animal manure, slurry, and poultry litter exhibited the highest loads for sulfonamides, tetracyclines, fluoroquinolones and macrolides (80, 470, 885, and 4,487 ng g−1 wet weight, respectively) with nor- and ciprofloxacin serving as markers for anthropogenic sources. In compost and digestate, antimicrobials were found to be almost always below the limits of quantification. Reused water from cWWTPs for irrigation in open-field lettuce production were contaminated in the range of 12-221 ng L−1 with sulfonamides, tetracyclines, and fluoroquinolones, compared to very few detected in channels and surface waters. The Antimicrobials Hazard Index (HI), based on the Predicted No Effect Concentration for Antimicrobial Resistance (PNECAMR), was significantly >100 in contaminated topsoil improvers from urban and animal sources. Accounting for worst-case inputs from topsoil improvers and irrigation water, as well as dilution factors in amended soil, fluoroquinolones only exhibited an HI around 1 in open fields for lettuce production. The origin of topsoil improvers plays a pivotal role in ensuring safe and sustainable leafy vegetable production, thereby mitigating the risk of Antimicrobial Resistance (AMR) onset in food-borne diseases and the transfer of AMR elements to the human gut flora.

Modeling and Parameter Optimization of Plant Factory Production System Under Low-Carbon Constraints

Highlights A life cycle approach to modeling the carbon footprint of leafy vegetables. Determine the optimal design parameters through logical and mathematical relationship derivation. The simulation model of leaf vegetable production line was established. The optimal parameter scheme was determined by multifactorial simulation tests. Abstract. In recent years, a plant factory has gradually become a new model of facility agriculture, and the optimization problem of low-carbon design of production system in a plant factory has become more prominent. In the design of the production system, needs of high efficiency, high yield, and low carbon emission must be considered. In this study, the leafy vegetable factory is taken as the research object, and the carbon footprint calculation model of products is established based on the life cycle assessment method. Taking production capacity and carbon footprint as design indicators, the logical correlation and mathematical relationship between them and production line design parameters are analyzed layer by layer to determine the key design parameters. The leafy vegetable production line is modeled by plant simulation software, and multifactor simulation experiments are set up to explore the influence of key design parameters on design indexes to guide the optimal decision of parameter design scheme. The new design scheme increases the productivity of the plant factory by 35.40%, reduces the carbon footprint of leafy vegetables by 15.54%, and solves the problem that leafy vegetables at the bottom of the planting frame in the original plant factory grow poorly because of insufficient light. Keywords: Carbon footprint, Life cycle assessment, Plant factory, Product system, Production line modeling.

Cultivation practices of leafy vegetable production during the wet season in Ambon, Indonesia

Green cabbage, water spinach, and spinach are important vegetables in the diet of the Ambonese communities, so the vegetables have economic value and contribute to the inflation of Ambon City. The main obstacle for optimizing leafy vegetables in urban farming of Ambon City in Ambon Bay neighborhood is excess water during the rainy season which possibly induces plant diseases and reduces the yield. The purpose of this study was to verify the 11-year weather of Ambon Bay; and the adaptation of vegetable farmers in Ambon City to the change of rainy season as well as precipitation in the study location The research was conducted using a qualitative descriptive method based on interviews with farmers supported by climate data for 11 years. This study explains that the rainfall was variable during 10 years; In 2010-2013 and 2017-2020, the annual rainfall was 3.950-5.264, while in 2014-2016 it ranged from 2.017-2.995 mm. Farmers adapt to high rainfall by installing plastic rain shelters, shortening the planting distance from 20 cm to 10 cm, and changing the planting calendar. However, in general growers install rain shelters during vegetable cultivation in the wet season resulting in high productivity of leafy vegetables.

Comparative Analysis of Leaf Vegetable Productivity, Quality, and Profitability among Different Cultivation Modes: A Case Study

In recent years, vegetable production has been in the transitional stage from traditional cultivation mode to modern cultivation mode. Therefore, evaluating the actual productivity and economic benefits of different cultivation modes is instructive for leafy vegetable production. This research chose a vegetable production company (Shanghai, China) as a demonstration case to cultivate various leaf vegetables under different cultivation modes (hydroponic, substrate, and soil cultivation). By investigating the yield and quality of vegetables, as well as all production costs and selling prices, we drive a comparative evaluation of comprehensive features and economic benefits of different cultivation modes. The results showed that leafy vegetables cultivated by hydroponic mode gain the highest fresh weight at the early growth stage, but the greatest unit yield (0.98~1.21 kg·m−2) emerged under the soil cultivation mode. Vegetables grown under substrate mode had the best comprehensive quality with high soluble solids content and low nitrate content. The unit costs of the soilless cultivation modes (8.26~10.3 CNY·m−2) were 3–4-fold higher than that of soil cultivation, mainly due to the high fixed costs and input costs, especially for substrate mode. According to actual prices, the soil cultivation mode had the highest economic benefits as a whole (4.83~8.83 CNY·m−2), and only hydroponic cabbage which had comparable yield gained considerable benefits (8.94 CNY·m−2). Quality-based pricing scheme can make substrate mode achieve profitability. The pricing scheme that guarantees a 40% revenue is within acceptable limits for consumers. Based on this actual production case, it can be concluded that a low unit yield of hydroponic mode and a high unit cost of substrate mode are the predominant factors affecting their profitability and economic viability.

Growth, development and yield of safflower genotypes in response to environmental variations

Safflower (Carthamus tinctorius L.) is a crop that is drought tolerant and grown in arid and semi-arid lands (ASALs) for its commercial utility as vegetable oil, animal feed, cut flower, leafy vegetable, pharmaceuticals, foods colorant, textile dye, cosmetics, and biofuel production. These important attributes make safflower an ideal crop to diversify the economy and improve the socioeconomic status of many smallholder farmers in ASALs. This study evaluated the growth, development, and yield of five safflower genotypes in three different locations in the southern part of Botswana under farmers’ fields during winter and summer. The results showed that there was a significant (P ≤ 0.05) genotypic variability for all phenological development (days to emergence, stem elongation, and flowering), plant growth (plant height and shoot biomass), the yield and yield components (number of branches/plant, number of capitula/plant and 1000-seed weight), oil content and oil yield. However, genotypes did not vary significantly (P ≥ 0.05) in number of primary branches/plant. The results showed that winter planting significantly (P ≤ 0.05) promoted safflower growth and yield than planting in summer. The growth, development, yield, and yield components of safflower genotypes varied across locations with Ramonaka being the most favorable. The GGE biplot revealed that genotype Kenya-9819 was found to be the most stable and adaptable with above-average yields. Sebele winter planting was the best representative environment and most suitable for discriminating genotype performance. The genotype by yield*trait combination (GYT) biplot revealed that genotypes ranked as Kenya9819 > Turkey > Sina > PI537636 > Gila. The results suggested that safflower was best planted in winter and that Kenya9819 was the best genotype to be planted in the greater Gaborone region.

Effect of Furrow Straw Mulching and Straw Decomposer Application on Celery (Apium graveolens L.) Production and Soil Improvement

Straw mulching on wet beds is an effective method to alleviate continuous cropping obstacles in greenhouses. However, this technique cannot be applied in the production of leafy vegetables with high planting density. Straw mulching in furrows is an alternative method in this circumstance. In this study, celery (Apium graveolens L.), a vegetable that prefers a high planting density and wet soil, was used to test furrow straw mulching technology, and the effect of different straw amounts and straw decomposers on soil improvement and celery production was investigated. The results showed that straw mulching in furrows significantly reduced soil conductivity and nitrate nitrogen levels, increased the contents of soil organic carbon as well as phosphorus and potassium nutrients in the bed, and improved celery yield and quality, indicating the significant lateral movement of released nutrients between the furrow and bed. The positive effects of 15,000 kg/ha straw application were more pronounced than those of 7500 kg/ha and 11,250 kg/ha. In addition, straw decomposers accelerated nutrient release and improved celery yield and quality. A decomposer named “ZhuBang” containing Bacillus licheniformis was the most effective. We concluded that furrow straw mulching combined with straw decomposer application is an effective measure for the sustainable production of leafy vegetables in intensive vegetable production facilities.

Farmers’ Knowledge, Attitudes and Practices in the Production, Preservation and Utilization of African Leafy Vegetables in Western Kenya

A large diversity of African Leafy Vegetables (ALV) are consumed in the western Kenya. These vegetables have been neglected leading to persistent high cases of malnutrition and micronutrient deficiencies. To boost the promotion of these vegetables, which has been ongoing by various organizations, a study was conducted with the objective of determining the farmers’ knowledge, attitudes and practices in the production, preservation and utilization of ALV in Kakamega and Vihiga Counties, Kenya. Twelve gender-disaggregated Focus Group Discussions were held. Visiting institutions, family and friends were the leading sources of knowledge. ‘How to grow ALV’ was the most favourite topic delivered. Nineteen different ALV species are consumed in Western Kenya. Vegetables for the market are harvested when there is no direct sunlight. Most vegetables are mixed when cooked. Duration and methods of cooking vary. Vegetables which have been domesticated for long are sold as much as they are home consumed, while the wild and those domesticated recently are not sold. Preservation for long periods was rare. Thirteen ALV are encouraged for specific individuals for health benefits. Twelve ALV are discouraged for specific individuals because of myths. The farmers have reasonable knowledge regarding ALV. Attitudes and practices are influenced by culture.

Agricultural practices and intestinal parasites: A study of socio-environmental risk factors associated with leafy vegetable production in La Plata horticultural area, Argentina

Foodborne diseases now represent one of the most important public health problems. The objectives were to analyze the leafy vegetables and crop soil to detect parasitic species and evaluate the factors that increase the risk of parasitic contamination in the productive units in La Plata horticultural area. The study included 261 leafy vegetable and 87 crop soil samples that were processed using washing, sedimentation, and flotation techniques. Socio-environmental characteristics and agricultural practices were surveyed, and a generalized linear model was used to assess the change in parasitic prevalence with different predictor variable. The 58.6% of leafy vegetable and 31.0% of crop soil samples contained parasitic species, the most prevalent being Blastocystis sp. and oocysts of Cryptosporidium spp. Risk factors were the limited access to health, dirt roads, children and dogs circulating in crops, field cultivation, furrow irrigation and lettuce cultivation. The high prevalence of intestinal parasites in the vegetable crops was mainly associated with the conditions of structural precariousness in the production units. These results elaborated with the participation of the population, provide valuable knowledge for the planning of epidemiological programs that include environmental health as a fundamental nexus in health campaigns.

Response of Black Nightshade to Different Cropping Systems and the Effect on Physiological Parameters and Mineral Composition

In southern African countries, production of indigenous leafy vegetables is commonly practiced at home garden and/or commercial level due to their significant contribution toward eradication of hunger, food insecurity, and malnutrition. Black nightshade (Solanum nigrum L.) is among African leafy vegetable (ALV) highly recognised for its pharmacological and nutritive benefits. Several research have shown that ALVs can be cultivated in the open field or greenhouses, however, little information is available on the changes of the agronomical parameters and mineral composition. The aim of the study was to compare the physiological parameters and mineral composition of nightshade grown in the open field vs. greenhouse cropping systems. The results of the study revealed high-leaf area and relative chlorophyll content in the open field conditions while plant height and the number of leaves were reportedly higher under the greenhouse system. Minerals elements such as magnesium, copper, manganese, iron, zinc, and aluminium were significantly higher in the open field cropping system, while greenhouse cultivation recorded higher sulphur and boron. Notably, no significant amount was observed in calcium, phosphorus, potassium, and sodium between open field and greenhouse system. Furthermore, a significant amount of total nitrogen was reported in the open field, however, no significant difference was observed in moisture and ash content for both cropping systems. In conclusion, black nightshade cultivated in open field provided higher leaf chlorophyll, leaf area, and trace elements compared to greenhouse cultivation while macro minerals concentration had no significant difference in both cropping systems.

Effects of daily light integral and photoperiod with successive harvests on basil yield, morpho-physiological characteristics, and mineral composition in vertical farming

In recent years, vertical farming is becoming increasingly popular for the production of leafy vegetables and aromatic herbs, such as basil (Ocimum basilicum L.). However, research has focused primarily on the effect of light quality levels, quantity, and photoperiod in order to define more energy-efficient basil growing protocols. Although scientists have underlined the positive response of this poliedric aromatic herb to successive harvests, this technique had not been investigated under sole source lighting with crop grown in a vertical farming cultivation. Two experiments were carried out in which the effects of two daily light integrals (DLI, 7.5 and 15 mol m–2 d–1) and three photoperiods (P, 14/10, 16/8, and 18/4 photoperiod/dark period) were evaluated in relation to two successive harvests on Genovese basil. In the first experiment, at the first cut, a DLI of 15 mol m–2 d–1 improved yield, yield parameters, and morphophysiological characteristics, but reduced incident light use efficiency (LUE), compared to a DLI of 7.5 mol m–2 d–1. At the second cut, irrespective of the DLI used, plants grown at the first cut with a DLI of 15 mol m–2 d–1 did not show significant differences in plant fresh biomass. In contrast, for plants grown at the first cut with a DLI of 7.5 mol m–2 d–1, the DLI of 15 mol m–2 d–1 used at the second cut improved yield and photosynthetic performance. Regardless of photoperiod, the cuts increased fresh biomass and DLI by 205.1% (on average), confirming how this pre-harvest factor can be used to achieve desired yield and quality from basil with potentials to enhance LUE and resource savings in the vertical cultivation.

Role of Phosphate Solubilizing Rhizobacteria in Growth and Productivity of Green Leafy Vegetables. A Review

Chemical based phosphate (PO4-3) fertilizers occupies significant place in agricultural domainand ought to be dangerous (e.g. cause chronic kidney disorders, eutrophication). Hence, world isyelling for an efficient substitute of PO4-3 fertilizer. This fertilizer is being used to escalate yieldof green leafy vegetables, which are loaded with health nutrients, consequently, world is fallingfor this Mediterranean mode of diet. Phosphate Solubilizing Rhizobacteria (PSB) could come tothe rescue and would be an economical and ecofriendly substitute of such fertilizer. This reviewdraws attention of researchers, to unveil the understudied aspects i.e. role and mechanisms ofPO4-3 solubilization, driven by PSB in association with green leafy veggies (viz, Cabbage,Spinach, Lettuce). As found that PSB application could give desirable results i.e. uplift theproductivity of green leafy vegetables and one if designed as biofertilizer, could ameliorateharmful effects of such fertilizer, caused upon human consumption

Effect of Light Intensity and Spectra on Inorganic Constituents in Vietnamese Coriander (Persicaria odorata (Lour.) Soják)

With the aim of optimizing resources in regional production of nutritive valuable leafy vegetables, this study was conducted to obtain more knowledge regarding the interdependencies between light conditions and accumulation of inorganic constituents. The test plant, P. odorata, was cultivated in a climate chamber with fluorescent tubes as the main light source and daylight integrals (DLI) varying between 4.68 and 9.06 mol·m−2·day−1. The average DLI in greenhouse experiments was 41.55 mol·m−2·day−1. Light conditions were modified using additional LEDs (443, 515, and 629 nm) or by covering the plants with photoselective plastic films, leading to a lower DLI and modified light spectrum, especially by reducing the green spectral range. Contents of nitrate, phosphorus, potassium, magnesium, calcium, and iron, biomass accumulation, and water content were analyzed. In terms of particular light modifications, additional green (515 nm) and red (629 nm) LEDs showed reducing effects on nitrate content at both cultivation locations. Other inorganic constituents were affected differently depending on cultivation location. However, the calculation of average partial correlation coefficients enabled a more general statement. Increasing DLI correlated positively with contents of magnesium, nitrate, and potassium but negatively with contents of calcium and iron. Additionally, nitrate content correlated positively with the spectral range of 651–700 nm but negatively with the R:FR ratio. Consequently, a general recommendation related to the light conditions is not possible, as inorganic constituents were affected differently. Nevertheless, as the nitrate content in leafy vegetables is of high concern and was reduced by higher shares of green or red light, this might be one way to regulate nitrate content in leafy vegetables.

Influence of biofertilizer produced using drumstick (Moringa oleifera L.) unused parts on the growth performance of two leafy vegetables

The non-edible parts of Moringa oleifera, such as stems, branches or leaf petioles, have often been discarded while the leaves are consumed as a vegetable or are used to produce organic fertilizer. This study aimed to determine the optimal conditions for producing Moringa organic fertilizer (MOF) from previously unused parts and to compare these fertilizers with cow manure and bio-organic fertilizer. Seventy kilograms of the unused Moringa parts were blended with fifty kilograms of manure, 0.2 kilogram of Trichoderma-based product and two kilograms of superphosphate. The mixture was incubated at different intervals, including 5, 7 or 9 weeks. Next, the effects of MOF on the growth, yield, ascorbic acid content and Brix of lettuce and mustard spinach were also determined and compared with other organic fertilizers (cow manure and bio-organic fertilizer). Results of the study revealed that 25 tons per ha of MOF were significantly superior to those treated with cow manure and bio-organic fertilizer in the case of vegetable yields. Further, 7 weeks of MOF incubation was found suitable to produce an optimal yield during the various incubation period. These results suggested that the Moringa non-edible parts can make organic fertilizer and enhance growth, yield, and leafy vegetable production.

Insectos asociados a trampas cromáticas en seis cultivares de lechuga (Lactuca sativa) con manejo orgánico en un huerto agrícola de la costa peruana

Lettuce (Lactuca sativa L.) is a vegetable that presents versatility in cultivation techniques. Currently, research related to the productive behavior of cultivars and the evaluation of pests and diseases is being conducted. To minimize the damage of phytophagous insects in the production of leafy vegetables, the use of sticky traps of different colors has been recommended. Therefore, the purpose of this work was to identify the insects associated with the lettuce (L. sativa) crop trapped based on the chromatic trap (yellow and blue), using Razecol 100® (agricultural adherent), during the period from September to October 2022, under the Vegetable Research and Social Projection Program of the Universidad Nacional Agraria La Molina, Lima, Peru. 866 individuals were distributed in six orders (Diptera, Hemiptera, Lepidoptera, Coleoptera, Neuroptera, and Hymenoptera), and nine families were collected. The beneficial predatory fly of the genus Condylostylus (Diptera: Dolichopodidae), was dominant, with 314 specimens, and was also the most abundant in the vegetable production ecosystem. In four of the five temporary sampling units, specimens of the genus Agapostemon(Hymenoptera: Halictidae) and the blue color were preferred by this genus. The efficiency of yellow and blue traps in the control of pests associated with lettuce was demonstrated.

Leaf Vegetable Cultivation in Cameroon: An Overview of the Situation in Njombe and Surrounding Areas

Over the past ten years, it has been noted that the demand for leafy vegetables in the coastal area of Cameroon is increasing, particularly in the district of Njombe-Penja. Despite this growth in production volumes, there are also more or less severe shortages at certain times of the year. The main causes behind the variations in vegetable production in the Littoral zone are not well known and/or not recorded. In order to sort out the different factors (vegetable varieties, planting period, use of fertilisers and pesticides, soil, etc.) that interact on the production of leafy vegetables in the Littoral zone, it became necessary to conduct a study reviewing the state of leafy vegetable production and marketing activities in the locality of Njombé and its surroundings. This study also aims to better identify the main distribution chains and their vitality related to the markets supplied by vegetable production in the Njombe area. The methodological approach involved random sampling to constitute a population of 100 individuals (farmers, traders, etc.). A survey questionnaire was developed and administered to the target sample. The main results show that 96% of the individuals practising vegetable cropping are uneducated women, aged between 20 and 64 years. The individual areas cultivated are mostly very small to medium (between 64m² and 870 m²). The vast majority of the cultivated land is rented (80%). The most cultivated leafy vegetable varieties are, in order of importance: “Black nightshade” (100%), “African Eggplant” (84%), “green amaranth” (80%), “bush okra” (80%), “Hibiscus” (40%), and “Water leaf” (32%). The seeds used come mainly from local markets (60%). The use of fertilisers and pesticides (doses and application frequencies) is not mastered by the farmers. The major constraints to production are: the difficulty of obtaining good quality seeds (86%), fungal diseases (80%), and attacks by various pests. This study also highlighted the economic potential of this vegetable activity in the locality.

Fecal Contamination in the Wastewater Irrigation System and its Health Threat to Wastewater-Based Farming Households in Addis Ababa, Ethiopia

Due to rapidly growing demand, the production of vegetables is increasing along the Akaki Rivers. The objective of this study was to examine the degree of fecal contamination and levels of fecal contamination and dissemination throughout the wastewater irrigation system. Irrigation water, irrigated soil, and leafy vegetables were collected twice during 2 vegetable growing seasons, at the maturity period of the growing season, from 19 sampling points along the 2 Akaki Rivers. Composite samples were taken from all sampling points and E.coli was enumerated. The mean E.coli load in wastewater and non-wastewater sources were 1.16±5.53 CFU/100 ml and 2.232±1.292 CFU/100 ml respectively. All counts of E. coli in the wastewater exceeded the WHO’s standards indicating that the irrigation water quality was unacceptable. In the wastewater-irrigated and non-wastewater-irrigated soil, the mean E.coli were 3.62 ±1.582 CFU/g and 1.322±87.1 CFU/g respectively. Meanwhile, the mean E.coli counts on the lettuce and Swiss chard were 78 ± 2 CFU/g and 44 ±3CFU/g respectively. The E.coli count on the leafy vegetables was found to be associated with the E.coli in the wastewater and soil. The production of leafy vegetables using wastewater with unacceptably high levels of E.coli and high occupational exposure introduces high levels of risk to the farming communities and to the consumers. Leafy, low-growing raw edible vegetables need careful treatment during food production and harvesting procedures or activities.

Leafy vegetables production, marketing and constraints in Buea Subdivision of the Southwest Region of Cameroon

With the increasing population and to cope malnutrition, vegetable production is necessary in Buea. This study was conducted to identify the production, marketing and constraints to leafy vegetables production in Buea, Cameroon. Questionnaire/interview and field surveys were carried out with vegetable farmers. The results showed that female, as well as educated farmers were found to be more involved in vegetable cultivation than their male counterparts. Six vegetables; waterleaf, huckleberry, Amaranthus, bitter leaf, anchia and ongaonga were outstanding as preferred by farmers and consumers. Vegetables were cultivated in different cropping systems. Monoculture cropping was rare and was practiced averagely only on 24.5% of the farms. Mono- mixed cropping was observed on 10% of the fields and 65.5% of the farms had mixed cropping system with other plant species other than vegetables. Most of the land used for cultivation were hired. Seed source were 63.3% from farmers’ farm as against 36.7% from the local market. Average of 180, 160 and 130 bundles were harvested biweekly for huckleberry, bitter leaf and water leaf respectively while ongaonga, amaranth and anchia, had an average of 20, 40 and 20 bundles respectively. The prices per bundle of vegetables varied from 200 to 700 cfa. Farmers, wholesalers and retailers were involved in the supply chain. Lack of farmland, decrease in soil fertility, lack of inputs, lack of certified seeds, high cost of labour for weeding, market related issues and diseases were constraints faced by farmers. These constraints not only aggravate the misery of farmers but also contribute to the loss of the region's economic influence in vegetable production. In order to ameliorate these difficulties, it is therefore essential to practice intensive cultivation with more inputs and especially using certified seeds.

Yield response of African leafy vegetables to combined manure and urea microdosing in West Africa

Description of the subject. Fertilizers microdosing was tested for African leafy vegetables (ALVs) production to reduce the high rates of fertilizers usually applied to their production in West Africa. Objectives. This study aims to (i) evaluate the response of three ALVs (Amaranthus cruentus L., Solanum macrocarpon L. and Ocimum gratissimum L.) to cattle manure combined with urea-N microdosing and application timing and (ii) assess their partial factor productivity. Method. On-station trials were carried out over three growing seasons (2015 to 2017) in Northern Benin. Urea-N rates of 0, 10, 20, 30, 40 and 60 kg urea-N·ha-1 combined with 5 t·ha-1 of cattle manure (M5N0, M5N10, M5N20, M5N30, M5N40 and M5N60, respectively) and sole application as control (40 (M0N40) and 80 kg urea-N·ha-1 (M0N80)) and two urea-N application timings (T1 = 0 and T2 = 14 days after transplanting) were tested in a randomized complete block design with four replications. Results. The M5N60 treatment resulted in the highest A. cruentus fresh yield and improved leaf yield by 90 and 151% compared to M5N0, and the average of the two no-manure input treatments M0N40 and M0N80, respectively, while M5N40 treatment improved S. macrocarpon fresh yield the best by 23% compared to M5N0. For O. gratissimum, no significant difference was found between urea-N microdose rates. Besides, urea fertilizer application timing affected neither fresh yields nor partial factor productivity for any studied ALVs species. Conclusions. Reduced combination of urea-N and cattle manure is a promising nutrient management practice for ALVs production in West Africa as it improved yields while saving fertilizer for smallholder vegetable farmers.

Growth and Yield Responses of Leafy Vegetables Grown in Organic and Conventional Agriculture Systems

Several scientific reports indicate lower as well as higher relative yield stability in organic and conventional (chemical) agriculture systems. This study present results of on-farm trials conducted on leafy vegetables grown in in organic and conventional management systems. Four leafy vegetables collard green (Brassica oleracea cv. acephala), kale (Brassica oleracea cv. sabellica), lettuce (Lactuca sativa) and swiss chard (Beta vulgaris L. cv. cicla) were grown in organic and conventionally managed plots in the spring 2018 and 2020. United States Department of Agriculture (USDA), National Organic Program (NOP) standards were followed for cultural and management practices in organically managed experimental field plots. Synthetic chemical inputs (seeds and fertilizer) were applied in the experimental field plots managed in conventional production system. Data on plant height, leaf number and total fresh weight of leafy vegetables were measured at the end of the experiment. Results showed that maximum fresh weight per plant was obtained from conventionally grown kale and the lowest was recorded in conventionally grown lettuce. The fresh weight of collard (344.1 g/plant) and kale (475.6 g/plant) was significantly higher in conventional system relative to the organic management system in collar (184.9 g/plant) and kale (242.3 g/plant). In contrast, for lettuce, significantly greater fresh weight was obtained in the organic (266.5 g/plant) compared to conventional (189.3 g/plant). No difference recorded in fresh weight of swiss chard grown in organic (222.0 g/plant) and conventional (263.7 g/plant) production systems. No difference observed in plant height and number of leaf count between the two production systems. Findings suggest that growth and yield responses in organic and conventional production systems can vary with the individual crop species. Results presented could be helpful to growers in planning for the organic production of leafy greens vegetables.

The Alleviation Effects of Biostimulants Application on Lettuce Plants Grown under Deficit Irrigation

Τhe aim of this study was to examine the potential of using biostimulants for the amelioration of deficit irrigation effects on field-grown lettuce plants growth parameters (cv. Doris (Romaine type) and cv. Manchester (Batavia type)). Therefore, five biostimulatory products that differed in their composition were evaluated, including seaweed extracts, amino acids, humic and fulvic acids, macronutrients, Si, and vegetable proteins, while a control treatment with no biostimulants applied on plants was also considered. Plants were subjected to three irrigation regimes, e.g., rain-fed plants (RF), deficit irrigation (I1; 50% of field capacity) and normal irrigation (I2; 100 of field capacity). The results indicate that the application of seaweed extracts, macronutrients, and amino acids (SW treatment) alleviated the negative effects of deficit irrigation on plant growth and chlorophyll content of Romaine-type plants. On the other hand, Batavia-type plants were more susceptible to water stress, since the highest crop yield plant was observed under the full irrigation treatment and the application of vegetal proteins and amino acids (VP treatment). In general, the application of biostimulants on the Romaine type improved plant growth under water shortage conditions compared with fully irrigated plants in almost all measurements, whereas the Batavia-type plants appeared to be more sensitive to deficit irrigation. Therefore, the ecofriendly practices of deficit irrigation and biostimulant application could be useful in leafy vegetable production on a genotype-depended manner.