Production Of Leafy Vegetables Research Articles

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.

Home gardening in Singapore: A feasibility study on the utilization of the vertical space of retrofitted high-rise public housing apartment buildings to increase urban vegetable self-sufficiency

In land-scarce cities, high-rise apartment buildings may provide vertical spaces for natural-light home gardening along corridors, rooftops, balconies as well as façades. The vertical space can improve not only urban environmental sustainability but also food security. Using an experimental approach, we investigated the food production potential of a high-rise public housing apartment building based on different gardening systems, food crops, and sunlight availability. A gardening prototype system for building corridors was shown to increase the unit area yield of corridor gardening by fivefold compared to a commercial trough planter system. Additionally, this commercial trough planter system was mainly for leafy vegetable production, whereas the gardening prototype system for corridors is also suitable for climbing crops, such as legumes and cucurbits. Nevertheless, because of the limited space along corridors of the apartment building and the relatively low-light levels on average, corridor gardening was estimated to meet only 0.5 % of the demand for vegetables of the residents living in the apartment building. Rooftop gardening with shallow growing medium (depth < 15 cm) was estimated to meet 3 % of demand, and façade gardening 43 %, given the larger space available. Although the vegetable production potential in this study was estimated based on a particular typology of public housing apartment buildings in Singapore, our results showed that vegetable production in public housing apartment buildings is feasible, and home gardening can produce a substantial amount of vegetables for consumption if well deployed. Governments of highly urbanized cities may wish to invest in better home garden designs for high-rise public housing apartment buildings and encourage residents’ participation in home gardening, which would increase high-rise greenery coverage and improve urban food system resilience. Future studies should also investigate the environmental sustainability and food safety aspects of home gardening in highly urbanized cities.

Effects of growing media and fertilization rates on the organic production of baby leafy vegetables

Effects of growing media and fertilization rates on the organic production of baby leafy vegetables

Adoption of technological innovations in production of leafy vegetables in Sweden

Adoption of technological innovations in production of leafy vegetables in Sweden

Contribution of Superabsorbent Polymers to Growth and Yield of African Leafy Vegetables

Superabsorbent polymers (SAPs) have been used as water-saving materials for limited irrigation water resources in arid and semi-arid areas. The purpose of this study was to optimize SAP application dosage and irrigation intervals on the growth of African leafy vegetables (ALVs) under greenhouse conditions. A factorial experiment was conducted under greenhouse conditions to determine the optimal SAP application, dosage, and irrigation intervals for the growth and production of African leafy vegetables. Two species of African leafy vegetables were studied: cowpea (Vigna unguiculata) and African nightshade (Solanum scabrum). The experiment was performed in a randomized complete block design comprising 25 treatments: a factorial combination of five superabsorbent polymer application doses (0 g, 0.5 g, 1 g, 1.5 g, and 2 g) SAP/Kg of soil substrate and five irrigation intervals (3 days, 4 days, 5 days, 6 days, and 7 days) with three replications. Statistical analysis of the results showed that the use of SAP in irrigation can significantly promote the growth and yield of African leafy vegetables. SAP, irrigation, and their interactions significantly affected ( P &lt; 0.005 ) the plant height, stem diameter, leaf area, number of mature leaves/plant, and dry weight of leafy vegetables. Treatment with SAP showed higher growth parameters and yield of vegetables compared to the treatments. Treatment with 1 g SAP/kg of soil substrate and 5-day irrigation interval recorded the highest plant growth and yield, with 24%, 11.7%, 11.1%, and 85.9% increase in cowpea plant height, leaf area, number of mature leaves, and dry weight/plant, respectively. The treatment with 1 g SAP/kg of soil substrate and 5-day irrigation interval was observed as the best for the optimal production of African leafy vegetables under greenhouse conditions. Hence, SAP could be a good strategy for food production within arid and semi-arid lands where water resources are scarce.

CLUSTER STRUCTURES IN DEVELOPMENT EMPLOYMENT OF RURAL TERRITORY OF THE REGION

The article outlines the current state of socio-economic development of the region in the direction of the social sphere. It was established that the current state of the socio-economic infrastructure of the village confirms the presence of a deep crisis. The difficult situation of the village economy, long-term underfunding of the social sphere led to the threat of physical destruction of its material and technical potential. The existing material base of cultural and household facilities does not meet the standards. In rural areas, educational facilities in most cases do not have modern technical equipment for teaching, there is a shortage of teaching staff, and the level of their professional education is lower than in the city. The problems of employment in the rural areas of the region are analyzed. It was found that the employed population, which is released from agriculture for various reasons, can engage in non-agricultural activities, which will positively affect the growth of the income of the rural population. Therefore, it is possible to use not only agricultural land, but also natural and recreational resources, as well as a favorable habitat. However, local authorities do not pay due attention to the development of agricultural activities in the countryside, livestock farms and agricultural processing enterprises are shrinking. It is proposed to form an agricultural-tourist cluster to ensure uninterrupted supply of ecologically clean agricultural products and to solve the issue of employment of the region’s population. Thus, as an example of such formation, the agricultural and touristic potential of the Berezan district was used, within which there are 4 recreation areas: “Koblevo”, “Lugove”, “Morske”, “Rybakivka”. About 170 recreation centers offer their services to tourists from Ukraine and near abroad. About 180,000 people visit the Koblevo-Rybakiv recreation area every year. In order to provide 180,000 tourists with environmentally friendly food during the 5 months of the holiday season, it is necessary to allocate 6.4 hectares of arable land for the production of leafy vegetables, early cabbage, early potatoes, seasonal vegetables, melons and sweet corn; 28.6 hectares of perennial plantations for the production of berries and grapes; 856 hectares of agricultural land for the production of food products of animal origin. For the production of fresh baked goods, the peasants must purchase high-quality flour of industrial production. When forming the production zone, it is necessary to take into account the need to minimize transport costs. It was emphasized that the cluster should include rural areas located along the M14 highway and no further than 20-25 km from the Koblevo-Rybakiv recreation area. These are rural settlements that are under the jurisdiction of the Koblev Rural United Territorial Community. The number of able-bodied population within its borders is 5,514 people.

Calcium induced growth, physio-biochemical, antioxidant, osmolyte adjustments and phytoconstituent status in spinach under heat stress

High temperatures profoundly limit the growth and productivity of leafy vegetables. Investigating heat-responsive morpho-physiological and biochemical mechanisms is an important tool for the thermo-tolerance of crops. This research work is about the response of varying levels of exogenous Ca2+ supplementation (0, 2, 4, and 6 mmol L−1) on growth & development, gaseous exchange, antioxidant enzyme activities, and osmolytes adjustments in spinach plants grown under heat related stress. A rise in temperatures from 25 to 35 °C decreased leaf area, number of leaves, chlorophyll contents, and leaf fresh biomass of spinach by 34.20%, 26.88%, 21.73%, and 24.68%, respectively. Meanwhile, Ca2+ treated plants showed higher antioxidant enzyme activities, soluble sugar levels, and lower membrane leakage induced by heat stress. Leaf osmotic potential values of seedlings treated with the Ca2+ solutions were measured to be lower than the control. Under heat stress, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) significantly increased in spinach leaves. Exogenous Ca2+ supplementation enhanced heat tolerance in spinach by the maintenance of physio-biochemical, and a decrease in membrane lipid peroxidation and presence of phytoconstituents. Thus, an appreciable level of thermo-protection was induced by 4 mmol L−1 Ca2+ under heat stress conditions, indicating that the Ca2+ level required for growth under heat stress exceeds that required level for normal growth, regulation of enzymatic antioxidants, and osmolytes adjustments under normal conditions.

Estimation of the Leaf Area Index, Leaf Fresh Weight, and Leaf Length of Chinese Chive (Allium tuberosum) Using Nadir-looking Photography in Combination with Allometric Relationships

In horticultural leafy vegetable production, continuously monitoring crop size indicators such as the leaf area index (LAI), leaf fresh weight (LFW), and leaf length (LL) is of practical value because these indicators are related to crop yields and harvest timing. The aim of this study was to develop a method that enables the continuous, automatic estimation of the LAI, LFW, and LL of a Chinese chive (Allium tuberosum) canopy by combining timelapse photography with allometric equations. LAI was estimated based on the gap fractions of nadir photographs (i.e., the fractions of nonleaf area), which were retrieved using the deep learning framework DeepLabv3+ with satisfactory accuracy (mean intersection over union, 0.71). This photographically estimated LAI (LAIphoto) corresponded well with the destructively measured LAI (LAIdest) (LAIphoto = 0.96LAIdest, R2 = 0.87). LAIphoto was then used as the input of allometric regression equations relating LAIphoto with LFW and LL. A power function (y = axb) fit the observed LAIphoto–LFW and LAIphoto–LL relationships well (R2 = 0.89 and 0.74, respectively). By combining nadir timelapse photography with the allometric equations, changes in the LFW and LL of a Chinese chive canopy were estimated successfully for a 9-month cultivation period. Our approach can replace time-consuming, labor-intensive manual measurements of these crop size indicators for Chinese chive and may be applicable to other crops with different parameter sets.

Foliar application of biosynthetic nano-selenium alleviates the toxicity of Cd, Pb, and Hg in Brassica chinensis by inhibiting heavy metal adsorption and improving antioxidant system in plant

Biosynthetic nano-selenium (bio-SeNP), as a plant growth regulator, has better bioavailability and lower toxicity than selenite and selenate. This study investigated the beneficial role of bio-SeNP in mitigating the adverse effects of multiple heavy metals (HMs, e.g., Cd, Pb, and Hg) on growth and yield of pak choi (Brassica chinensis) grown in slightly or heavily polluted (SP or HP) soil by regulating metabolic and antioxidant systems. The results revealed that foliar application of bio-SeNP (5, 10, 20 mg L−1 Se) at the 6-leaf stage greatly reduced the levels of Cd, Pb, and Hg in shoots and roots of pak choi. Application of 5 mg L−1 bio-SeNP significantly (p < 0.05) decreased the translocation factor (TF) of Cd, Pb, and Hg from root to shoot by 9.83%, 44.21%, and 46.99% for SP soil, 24.17%, 56.00%, and 39.36% for HP soil, respectively. Meanwhile, all bio-SeNP treatments led to a significant improvement in plants growth by enhancing the antioxidant defense system (e.g., AsA-GSH) and promoting chlorophyll synthesis as well as suppressed the lipid peroxidation products contents (MDA) in shoots. Moreover, the enhanced levels of mineral nutrient elements (e.g., Ca, Mg, Fe, or Zn) and organic selenium (e.g., selenocystine, Se-methylselenocysteine, and selenomethionine) in the edible shoots of bio-SeNP-treated pak choi plant under multiple HMs stress indicated the positive impacts of bio-SeNP on the improvement of shoot quality and nutritional values. Collectively, our results indicated that bio-SeNP play an important role in the management of multiple HMs-induced adverse effects on pak choi. Foliar application of bio-SeNP at appropriate concentration (≤ 5 mg L−1 Se) can be considered as a promising agronomic measure for safety leafy vegetable production in multiple HMs polluted soils when bio-SeNP application.

Microclimate control to increase productivity and nutritional quality of leafy vegetables in a cost-effective manner

Food security is one of the key global challenges in this century. In Singapore, our research team has been using novel aeroponic technology to produce fresh vegetables since 1997. Aeroponic systems allow for year-round production of not only tropical, but also sub-tropical and temperate fresh vegetables, by simply cooling the roots suspended in aeroponic systems while the aerial parts grow under tropical ambient environments. It has also been used to investigate the impacts of root-zone CO2 on vegetables by enriching root-zone CO2 while their aerial portions were subjected to constant atmospheric CO2. To compensate for the lack of available land, Singapore also needs to develop a farming system that can increase productivity per unit land area by many-fold. Over the past 10 years, my research team has established a commercially viable LED integrated vertical aeroponic farming system to grow different leafy vegetables under different LED spectra, intensities, and durations in the tropical greenhouse. The results demonstrate that it is possible to increase shoot production and rate of shoot production of leafy vegetables by increasing light intensity and extending the photoperiod under effective LED lighting. Furthermore, temperate vegetable crops such as lettuce were able to acclimate to high light intensity under supplementary LED lights to natural sunlight in the greenhouse. Supplementary LED lightings promote both leaf initiation and expansion with increased photosynthetic pigments, higher Cyt b6f and Rubisco protein contents on a per area basis and thus improve photosynthetic capacity and enhance productivity. Plants sense and respond to changes in their immediate environments (microclimate), manipulating the root zone temperature (RZT) and water supply will impact not only their growth and development but also their nutritional quality. Our on-going research aims to investigate if the nutritional quality of leafy vegetables could be improved under suboptimal RZT and mild water deficit through deficit irrigation. If substantial energy and water savings in urban farming can be achieved without substantial yield penalty but with higher nutritional quality, the amount of water and energy saved can bring substantial benefits to society. Keywords: leaf vegetables, LED lighting, microenvironment, nutrient spraying intervals, nutritional quality, photosynthetic performance, productivity, root-zone temperature DOI: 10.25165/j.ijabe.20221503.7367 Citation: He J, Qin L. Microclimate control to increase productivity and nutritional quality of leafy vegetables in a cost-effective manner. Int J Agric & Biol Eng, 2022; 15(3): 55–61.

Evaluating the Potential of Protected Cultivation for Off-Season Leafy Vegetable Production: Prospects for Crop Productivity and Nutritional Improvement

The effects of different protective structures on horticultural and nutritional yield of amaranth and water spinach were studied in three seasons of 2020–2021 in Taiwan. The number of people that can receive recommended dietary intake of iron and β-Carotene from vegetables grown under different production conditions was also estimated. The yield of white and red amaranths was consistently better (7.68–19.70 t/ha) under pink poly-net house in all the seasons, but the yield of water spinach was consistently better under white poly-net house (16.25–20.88 t/ha). Spider mite (fall &amp;amp; spring) and aphid (winter) infestation was mostly observed on all crops under poly-net houses. Neoxanthin, lutein and β-carotene were almost two-fold higher in red amaranth harvested from poly-net houses than open field. Based on the RDI values, β-Carotene supply to both men and women (14+) was consistently higher in all crops produced under pink ploy-net houses in all seasons, except for white amaranth produced under white poly-net house during winter. Its supply to 64,788 more men and 83,298 more women was estimated for red amaranth harvested from pink poly-net house than other production conditions. α-carotene was 2–3 fold higher in amaranths and water spinach harvested from poly-net houses than open field. The iron content of the amaranths was lower in poly-net houses (234.50–574.04 g/ha) than open field (645.42–881.67 g/ha) in the fall, but its supply from pink poly-net house was comparable with open field in the winter. However, pink poly-net house was the highest iron supplier from water spinach (323.90 g/ha) in the winter, which was estimated to provide iron to 19,450–22,939 more men and women than other production conditions. Both poly-net houses were the sole supplier of iron through amaranths in the spring, with pink poly-net house supplying iron to 2,000–5,000 more men and women. Thus, protected cultivation not only leads to more marketable yields but also results in higher quantities of health promoting nutrients. Hence, pink poly-net house may be considered to produce more nutritious vegetables, especially during the off-season to bridge the gaps in the seasonal variations in vegetable consumption, besides providing better income opportunities to the smallholder farmers.

Silicon leaf spraying increases biofortification production, ascorbate content and decreases water loss post-harvest from land cress and chicory leaves

Silicon (Si) leaf spraying can benefit the production and post-harvest quality of leafy vegetables, however the effect of Si application in land cress and chicory is unknown. This study aimed to verify Si supplementation by foliar spraying when using different sources and concentrations in content of Si and ascorbate in leaves, fresh and dry mass production, and water loss of chicory and land cress during storage. The experimental design was randomized in a 2 x 4 factorial scheme, with potassium silicate and sodium and potassium silicate stabilized with sorbitol, and four concentrations: 0 (control), 0.84, 1.68, and 2.52 g L −1 of Si. Tree foliar applications were carried out in four replications. Si foliar sprayings were applied every ten days; with the first application at 28 days after transplanting. It was determined that applying Si as a foliar spray was practical to increase the Si accumulation, plant growth, and biofortification as well as decrease the post-harvest water loss of land cress and chicory leaves. The Si concentration of 2.52 g L−1 as potassium silicate was recommended for foliar application in land cress and chicory.

황금 비단잉어를 이용한 Hybrid 바이오플락 아쿠아포닉 시스템과 수경재배 시스템의 엽채류 생산성 비교 연구

Aquaponics is a cultivation system that combines aquaculture and agricultural hydroponics. This study investigated the productivity of leafy vegetables cultivated in the hybrid biofloc technology-aquaponics (HBFT-AP) and hydroponics (HP). Yellow koi fish (Cyprinus carpio) were fed an EP diet containing 3% MKP (monobasic potassium phosphate, KH₂PO₄) for 10 weeks in the HBFT-AP. Leafy vegetables of 2 cultivar (ovired lettuce, volare lettuce) were employed in the experiment and water quality [dissolved oxygen (DO, mg/L), pH, water temperature (℃), electrical conductivity (EC; μs/cm), turbidity (NTU), TAN (NH₃ + NH₄SUP+/SUP) (mg/L), NO₂-N (mg/L), NO₃-N (mg/L) and PO₄-P (mg/L)] was measured 6 times a week. Leafy vegetables in HBFT-AP using yellow koi fish fed the EP with MKP 3.0% had a productivity somewhat higher (2 kinds of cultivar) compared to those in HP, and the pH in the HBFT-AP was maintained at the range around 6.0 for 7-10 week. During the 10-week feeding trial, concentration of NO₂-N was kept low in variability while total TAN, NO₃-N and PO₄-P levels increased with time in HBFT-AP. Higher values in hematocrit (PCV, %), hemoglobin (Hb, g/dL) and inorganic phosphorus (mg/dL) were found (P0.05) in fish at the end of the experiment compared to the fish at the beginning of the experiment (initial fish: 27.45%, 12.19 g/dL and 6.39 mg/dL; final fish: 36.26%, 14.52 g/dL and 11.21 mg/dL).

Comparison of vegetable production, resource-use efficiency and environmental performance of high-technology and conventional farming systems for urban agriculture in the tropical city of Singapore

Urban farming can improve cities’ food security and resilience, but the performance of different farming systems with respect to land and investment constraints has not been systematically investigated. Here, we compared conventional soil-based farming, vertical farming with natural lighting (Vnat), and indoor vertical farming. This study aimed to compare (1) the dynamic production of leafy vegetables over time given the same amount of investment and land constraints, (2) the associated water and energy use, and (3) the global warming potential (GWP) of the urban farming sector if each of the three farming systems was solely used in the tropical city-state of Singapore. A system dynamics (SD) model was constructed to map the potential quantity of leafy vegetables produced, together with the water and energy use of each farming system. The land and monetary investment constraints were set at an additional 0.3% of the total land area of Singapore and an annual investment of SGD 10–20 million (0.001–0.005% of Singapore's annual GDP). Vnat farming was predicted to have the highest production level (110,000 t) and self-sufficiency (76.9% of total demand) by 2050 based on the SD model. This would be >3 times the self-sufficiency level achieved by indoor and soil-based farming systems given the same investment and land constraints. Indoor farming was simulated to use <14% the land area of Vnat while soil-based farming exhausted the additional 0.3% of the land allocated. Indoor farming was also the most energy intensive system, requiring 100 times more than Vnat farming. Comparison of the GHG emission rates showed that indoor farming had the greatest GWP—at 2.51 kg CO2-eq per kg of lettuce produced. Our results suggest that Vnat farming may be the best form of urban farming system to provide large amounts of food in Singapore, considering the production level, the amount of resources used, and the environmental impacts.

Unveiling the social performance of selected agri-food chains in Costa Rica: the case of green coffee, raw milk and leafy vegetables

PurposeSeveral frameworks coincide in the importance of addressing social impacts to ensure sustainability. However, the agri-food sector, regarded as key in sustainable production, still neglects to identify potential social impacts when applying life cycle approaches. This work contributes to understanding the social performance of three agricultural products from a Latin American and Caribbean developing country as Costa Rica while recognising the challenges of Social-Life Cycle Assessment (S-LCA) application in this context.MethodsS-LCA represents a powerful technique to evaluate the potential social impacts of a product. Three case studies were analysed through S-LCA, using the subcategory assessment method (SAM) to characterise the social impacts and detect hotspots in the production of green coffee, raw milk and leafy vegetables. Primary data was collected through questionnaires to relevant informants and observations. In addition to secondary information, these data and information were used to assess eight impact subcategories for the farmer and worker stakeholder groups and nine subcategories for the local community.Results and discussionThe main results suggest that the Costa Rican institutional and market frameworks provide an enabling environment for a generally positive social performance in the studied cases. The assessed stakeholders can fulfil basic needs through access to inputs and services and achieve fair-trading conditions. Child labour, forced labour and evidence of environmental or health risks for the surrounding communities were absent. Important efforts to address the delocalisation, migration and child labour were observed, suggesting the potential development of social handprints in further studies. However, the farm production phase, related to farmers and workers, entails hotspots regarding social security and women’s empowerment. Moreover, farmers appear as the most vulnerable group because of their overall social performance.ConclusionsS-LCA helped identify relevant areas of intervention in the context of these particular case studies; however, further research and capacity building are recommended to tackle the detected challenges, both in the agri-food chains and in the use of S-LCA. Furthermore, these findings can aid in future decision and policy-making to improve and safeguard the positive social performance observed in the studied products.