Production Of Leafy Vegetables Research Articles

Virological Quality of Irrigation Water in Leafy Green Vegetables and Berry Fruits Production Chains.

This study condenses data acquired during investigations of the virological quality of irrigation water used in production of fresh produce. One hundred and eight samples of irrigation water were collected from five berry fruit farms in Finland (1), the Czech Republic (1), Serbia (2), and Poland (1), and sixty-one samples were collected from three leafy green vegetable farms in Poland, Serbia, and Greece. Samples were analyzed for index viruses of human or animal fecal contamination (human and porcine adenoviruses, and bovine polyoma viruses), and human pathogenic viruses (hepatitis A virus, hepatitis E virus, and noroviruses GI/GII). Both index and pathogenic viruses were found in irrigation water samples from the leafy green vegetables production chain. The data on the presence of index viruses indicated that the highest percentage of fecal contamination was of human origin (28.1%, 18/64), followed by that of porcine (15.4%, 6/39) and bovine (5.1%, 2/39) origins. Hepatitis E virus (5%, 1/20) and noroviruses GII (14.3%, 4/28) were also detected. Samples from berry fruit production were also positive for both index and pathogenic viruses. The highest percentage of fecal contamination was of human origin (8.3%, 9/108), followed by that of porcine, 4.5% (4/89) and bovine, 1.1% (1/89) origins. Norovirus GII (3.6%, 2/56) was also detected. These data demonstrate that irrigation water used in primary production is an important vehicle of viral contamination for fresh produce, and thus is a critical control point which should be integrated into food safety management systems for viruses. The recommendations of Codex Alimentarius, as well as regulations on the use of water of appropriate quality for irrigation purposes, should be followed.

Accumulation and Primary Metabolism of Nitrate in Lettuce (Lactuca Sativa L. Var. Youmaicai) Grown Under Three Different Light Sources

ABSTRACTLight-emitting diodes (LEDs) hold great potential as electric light source for leafy vegetable production in controlled environment. However, most of LED lights in vegetable cultivation were only combined with red and blue LEDs, and the spectral composition was oversample. Previous studies reported that light spectral composition could influence nutritional quality of vegetables, e.g., nitrate content. In order to better understand the influence of spectral composition on nitrate accumulation of leafy vegetables grown in closed-type system. The nitrate content, nitrate primary metabolism of 35-day-old lettuce (Lactuca sativa L. Var. youmaicai) in vivo and its biomass were investigated. The results showed that cool white fluorescent light (T5) and high-pressure sodium light (HPS) with wide spectrum significantly reduced nitrate content in lettuce than red and blue combination LED light (RB-LED) treatment. Our findings demonstrated that a proper optimizing procedure of light spectrum with supplemental other wavebands in RB-LEDs is necessary for reducing nitrate accumulation of lettuce.

Investigation of Microbial Contamination Level during Production of Baby Leafy Vegetables

Investigation of Microbial Contamination Level during Production of Baby Leafy Vegetables

Rooftop production of leafy vegetables can be profitable and less contaminated than farm-grown vegetables

Urban agriculture may solve issues of feeding urban populations. In China, for example, densely packed mega cities will continue to expand in number and size, necessitating increasing food miles. Interestingly, it has been estimated that the total rooftop space in China is about 1 million hectares, some of which can be converted for rooftop farming. Yet, despite some favorable reports on urban farming, the Chinese commercial sector has shown little interest. This may be explained by the dearth of data comparing urban and conventional farming. Therefore, we present here a feasibility study of hydroponically grown vegetables in a rooftop screen house in Guangzhou, China. From December, 2012 to May, 2014, we tested the production of seven leafy vegetables that are easily perishable and are not well suited to long-distance transport. We calculated the production cost and measured biochemical parameters. Results show that levels of vitamin C, potassium, calcium, magnesium, iron, zinc, and crude fiber were comparable to market counterparts. None of the roof hydroponic vegetables exceeded the maximum residue limit for lead, arsenic, cadmium, chromium, mercury, or nitrate. In contrast, 5 of 98 market vegetables were contaminated by exceeding the maximum residue limit for lead. Similarly 3 were contaminated for arsenic, 23 for nitrate, and 2 for organophosphate or carbamate insecticide. Compared to high-end vegetables sold on the market, rooftop-grown vegetables were competitive in cost and quality. Given that many countries have limited arable land to feed a large population, the widespread adoption of rooftop hydroponics could help expand the total area available for food production as well as meet the rising demand for safe high-quality vegetables.

Characterization and Documentation of Factors Contributing to Production and Consumption of African Leafy Vegetables (ALVs) in Kiambu and Kirinyaga Counties in Kenya

Characterization and Documentation of Factors Contributing to Production and Consumption of African Leafy Vegetables (ALVs) in Kiambu and Kirinyaga Counties in Kenya

Annual effects of different organic fertilisers in a baby leaf crops system under tunnel in Southern Italy

In a farm devoted to the production of fresh-cut leafy vegetables located in Eboli (Salerno), it was carried out a trial to compare the effects on crops and soil organic carbon (SOC) of biowaste compost, olive pomace compost, buffalo manure applied to soil in two doses (15 and 30 t ha−1 fresh weight). The amendments were tested in order to start in defining a feasible strategy for the recovery/maintenance of soils in degradation due to the organic matter depletion triggered by the intensive soil tillage and the lack of organic matter returned to soil. In the year following the soil amendment, it was studied the crop sequence: rocket-basil-rocket. Analysis of nitrates concentration in leaves of rocket was carried out on samples of all the treatments picked up in the two cycles of rocket. Along the year, we observed that the higher yields promoted in the first six months (May-September) from the dose 15 t ha−1, were obtained with the dose 30 t ha−1 in the successive six months (November-May). This was due, probably, to the larger stock of total N supplied with dose 30 and its release in time. Buffalo manure amendment showed a higher quickness than composts in the supplying mineral nitrogen to the first crops. On the other hand, nitrates in leaves of rocket exceeded, more frequently, the limits fixed in EU Regulation n. 1258/2011 in the plots amended with buffalo manure. Instead, the treatments with olive pomace compost showed to exceed rarely the EU limits. Under tunnel, the intensive management based on 4-5 crop cycles per year and as much soil tillage, appeared the first cause to explain the lack of significant variation in SOC of plots treated with organic improvers after one year from their distribution. This result let us to suppose the need to study some modifications of the standard farm management in order to reduce the number of soil tillage in a year and, as a consequence, the main stress causing the high carbon mineralisation rate in soil under tunnel.

Nitrogen flow in organic and conventional vegetable farming systems: a case study of Malaysia

High levels of nitrogen (N) are typically used in leafy vegetable farms to maximize production. However, such practice often leads to nutrient pollution. Hence, N balance in intensive leafy vegetable farm production must be explored to improve current farm management practices and to avoid environmental pollution. This study aimed to generate partial N balance in two organic (OF1 and OF2) and two conventional (CF1 and CF2) vegetable farms by employing material flow analysis/substance flow analysis in the STAN modeling software. Results showed that 31,556, 32,798, 19,498, and 19,337 t ha−1 y−1 of materials entered CF1, CF2, OF1, and OF2, respectively, and contributed to the nitrogen surplus levels of 1577, 1667, 2953, and 961 kg N ha−1 y−1, respectively. The STAN model revealed the presence of N surplus in the organic and conventional systems used in the study.

Seed production of African leafy vegetables: some experiences

Seed production of African leafy vegetables: some experiences

Irrigation Water Quality for Leafy Crops: A Perspective of Risks and Potential Solutions.

There is increasing evidence of the contribution of irrigation water in the contamination of produce leading to subsequent outbreaks of foodborne illness. This is a particular risk in the production of leafy vegetables that will be eaten raw without cooking. Retailers selling leafy vegetables are increasingly targeting zero-risk production systems and the associated requirements for irrigation water quality have become more stringent in regulations and quality assurance schemes (QAS) followed by growers. Growers can identify water sources that are contaminated with potential pathogens through a monitoring regime and only use water free of pathogens, but the low prevalence of pathogens makes the use of faecal indicators, particularly E. coli, a more practical approach. Where growers have to utilise water sources of moderate quality, they can reduce the risk of contamination of the edible portion of the crop (i.e., the leaves) by treating irrigation water before use through physical or chemical disinfection systems, or avoid contact between the leaves and irrigation water through the use of drip or furrow irrigation, or the use of hydroponic growing systems. This study gives an overview of the main problems in the production of leafy vegetables associated with irrigation water, including microbial risk and difficulties in water monitoring, compliance with evolving regulations and quality standards, and summarises the current alternatives available for growers to reduce microbial risks.

Improving nutrition security through agriculture: an analytical framework based on national food balance sheets to estimate nutritional adequacy of food supplies

An analytical framework is described for assessing the nutritional adequacy of national food supplies and the potential for addressing micronutrient gaps by increased crop production and crop diversity. The micronutrient contents of national food supplies of three countries (Bangladesh, Senegal, and Cameroon) were estimated using data from national food balance sheets. Population-adjusted nutrient requirements and identified nutrient short-falls, defined as not meeting the requirements of at least 80 % of the population, were also estimated. Linear programming models were used to determine a mix of crops that could meet the gaps the deficits of several nutrients while minimizing the use of additional agricultural land. Out of eight micronutrients included in the present analysis, six were identified as inadequate in Bangladesh and Senegal (vitamins A and C, riboflavin, folate, calcium, and zinc) and three were inadequate in Cameroon (vitamin A, calcium, and zinc). Adequacy of vitamins A and C could be met by increasing production of a few crops that are particularly dense in these nutrients (e.g., carrots or guava), which would necessitate only a small addition of agricultural land. Folate adequacy could be improved with increased production of legumes and green leafy vegetables, but with a greater requirement for agricultural land. Some micronutrient gaps, however, would probably have to be met by other means, such as enhanced livestock production, food fortification, biofortification, or imports. Despite the limitations of agriculture to meet the entire nutrient needs of a population, agricultural policy should consider the potential to improve nutrient adequacy with the crops currently available and by crop diversification.

Nitrate and oxalate in germplasm collections of spinach and other leafy vegetables

Accumulation of nitrate and oxalate is a concern in the production and marketing of leafy vegetables. High nitrate levels can be related to fertilization regime, light conditions and plant factors. Plant factors are of major importance for oxalate content. Plant breeding has been reported as one way of reducing the content of nitrate and oxalate. In this study we have examined germplasm collections of spinach (Spinacia oleracea), orache (Atriplex hortensis) and rocket (Eruca sativa). For spinach contents were related to morphological characters and to breeding method. Across accessions, rocket showed significantly higher nitrate levels than spinach and orache. No clear differences were detected between spinach and orache with regard to either nitrate or oxalate content. However, oarche showed higher dry matter content. A general strong positive correlation was found between nitrate and oxalate. The mechanism behind such a relationship is discussed but not fully understood. No differences were detected between old and new spinach cultivars or between open-pollinated cultivars and F1-hybrids, but potential interesting accessions for future breeding of low-nitrate/low-oxalate spinach were identified.

Virological fit-for-purpose risk assessment in a leafy green production enterprise

The purpose of the study was to provide an example of integrated monitoring and control of foodborne viruses using the assessment of one vertical production enterprise and the recommendations given to it. A risk assessment for virological hazards in lettuce was carried out based on the Codex Alimentarius framework, modified to consider viral hazards associated with fresh (whole) lettuce. The fit-for-purpose model was constructed by a complex process of: 1) identification of premises-selection of sampling sites, through the analysis of background information questionnaires based on HACCP audit principles and food safety fact-finding visits, 2) development of sampling guidance documents, 3) a half-year sampling campaign, 4) molecular analysis of the presence of index, human adenoviruses (hAdV) and human pathogenic viruses, noroviruses (NoVGI, NoVGII), and hepatitis A virus (HAV), 5) fit-for-purpose risk assessment, 6) development of a fit-for-purpose guidance sheet for the enterprise food safety manager for the prevention of contamination of leafy greens by viruses. Molecular virological analysis resulted in the detection of hAdV (55.65%, 123/221), and NoVGII (16.66%, 4/24), while NoVGI (0/55) and HAV (0/60) were not detected in the analyzed samples. HAdVs were detected in samples of all three phases (production, processing, and point of sale). The elevated prevalence of hAdVs supports the existence of routes of produce viral contamination. NoVs GI were detected at the point of sale in fresh lettuce heads, supporting the previous finding that pathogenic viruses can follow the routes of index viruses. NoVs GII were detected in irrigation water, harvesters' hands and manure samples, indicating sewage contamination of water, and unsatisfactory levels of hygiene concerning hands hygiene and use of toilet facilities. As a result of the study a fit-for-purpose guidance sheet was finally produced for the prevention of contamination of leafy green vegetables by viruses. The integrated monitoring and control process of the study can be applied to all leafy green vegetables production sites.

Prevalence and characterization of Escherichia coli and Salmonella strains isolated from stray dog and coyote feces in a major leafy greens production region at the United States-Mexico border.

In 2010, Romaine lettuce grown in southern Arizona was implicated in a multi-state outbreak of Escherichia coli O145:H28 infections. This was the first known Shiga toxin-producing E. coli (STEC) outbreak traced to the southwest desert leafy green vegetable production region along the United States-Mexico border. Limited information exists on sources of STEC and other enteric zoonotic pathogens in domestic and wild animals in this region. According to local vegetable growers, unleashed or stray domestic dogs and free-roaming coyotes are a significant problem due to intrusions into their crop fields. During the 2010–2011 leafy greens growing season, we conducted a prevalence survey of STEC and Salmonella presence in stray dog and coyote feces. Fresh fecal samples from impounded dogs and coyotes from lands near produce fields were collected and cultured using extended enrichment and serogroup-specific immunomagnetic separation (IMS) followed by serotyping, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. A total of 461 fecal samples were analyzed including 358 domestic dog and 103 coyote fecals. STEC was not detected, but atypical enteropathogenic E. coli (aEPEC) strains comprising 14 different serotypes were isolated from 13 (3.6%) dog and 5 (4.9%) coyote samples. Salmonella was cultured from 33 (9.2%) dog and 33 (32%) coyote samples comprising 29 serovars with 58% from dogs belonging to Senftenberg or Typhimurium. PFGE analysis revealed 17 aEPEC and 27 Salmonella distinct pulsotypes. Four (22.2%) of 18 aEPEC and 4 (6.1%) of 66 Salmonella isolates were resistant to two or more antibiotic classes. Our findings suggest that stray dogs and coyotes in the desert southwest may not be significant sources of STEC, but are potential reservoirs of other pathogenic E. coli and Salmonella. These results underscore the importance of good agriculture practices relating to mitigation of microbial risks from animal fecal deposits in the produce production area.

Production and Commercialisation Potential of Indigenous Leafy Vegetables: Case Study of Capricorn District in the Limpopo Province, South Africa

Aims: This study analyses the production and commercialisation potential of indigenous leafy vegetables (ILV) in the Capricorn district in the Limpopo Province of South Africa. Specific objectives were to identify the socio-economic characteristics of ILVs producers in rural areas of Capricorn district, investigate constraints faced by farmers in commercialising ILVs in rural areas of Capricorn district, determine the productivity of indigenous leafy vegetables in rural areas of Capricorn district, and to assess different types of marketing channels of ILVs in rural areas of Capricorn district. Study Design: The study used both qualitative and quantitative, cross-sectional data. The selection of ILV farmers within the study area was done using stratified random sampling procedure the strata being gender. Disproportionate random sampling procedure was used to select individual households. Methodology: The study used Stochastic Frontier Production Function to determine the productivity and to assess the socio-economic characteristics of producers of Indigenous Original Research Article Mahlangu et al.; AJAEES, Article no. AJAEES.2014.6.010 581 Leafy Vegetables. Bubble chart was also used to assess the marketing channels whilst consumer data was captured into a statistical package. Results: ILV famer’s significant socio-economic factors and production factors that constraint them from commercialising their products were found to be the amount of labor required, cost of hiring tractor service, land devoted to ILVs, gender, age, household size, farming experience, farm size, hired labour, primary occupation and land ownership. Results indicated that the productivity of ILVs in the study area varied among farmers; some farmers had a high productivity but most farmers had a low productivity. Conclusion: There is a great potential for commercialising ILV but there is a lot of work to be done in assisting farmers, for them to be sustainable and exploitation of these crops.

Alternative strategies for nitrogen fertilization of overwinter processing spinach (Spinacia oleracea L.) in Southern Italy

To identify the best practice for nitrogen (N) fertilization of overwinter processing spinach, two field experiments were carried out in the Foggia plain (Southern Italy), one of the most vocated area for leafy vegetables production. The field trials were aimed to define and suggest the proper fertilizer dose, typology and the right time of application. Experiment 1 evaluated four N fertilizer doses (0, 150, 225, 300kgha−1) in a two-year field trial. Experiment 2 was aimed to assess the effect of the split distribution of prilled urea fertilizer in comparison with the application of nitrification inhibitor (DMPP) containing urea fertilizer, broadcasted at sowing.Spinach yield, yield quality (nitrate – NO3− – and carotenoids content), N-use efficiency and risk of soil nitrate (NO3−-N) leaching were evaluated. The processing spinach yielded 37.8 and 3.6tha−1 of fresh and dry yield, respectively (average of the two experiments). Fresh and dry yield among the fertilizing treatments were similar. Also the β-carotene and the lutein content of spinach leaves (19.5 and 38.1mgkg−1, respectively) were not affected by the N fertilizer dose. Conversely, the N dose strongly influenced the NO3− content of the leafy vegetable tissues (1286mgkg−1 on average, 58% lower than the limits imposed by the EC regulation). As expected, the different rainfall pattern influenced both the leaf NO3− content and the risk of soil NO3−-N leaching. The results achieved demonstrated that, in order to get a favorable trade-off, among yield, yield quality, N-use efficiency and environmental impact, the processing spinach growers of the Foggia plain area should be encouraged to apply 225kgNha−1 as maximum fertilization rate. Also, the split urea fertilizer application appeared as the more effective strategy for N fertilization of overwinter spinach in comparison with the use of the nitrification inhibitor containing urea fertilizer, being the last strategy not able to adequately match the N crop demand.

Appraisal of hygiene indicators and farming practices in the production of leafy vegetables by organic small-scale farmers in uMbumbulu (Rural KwaZulu-Natal, South Africa).

During October, November and December 2011 (when highest sales of Agri-Hub fresh produce are observed), irrigation water, compost, lettuce and spinach sampled from four different farmer cooperatives supplying the local Agri-Hub in uMbumbulu (KwaZulu-Natal, South Africa) were analyzed monthly for the presence of total and fecal coliforms and Escherichia coli using the most probable number (MPN) technique. The pH values for all irrigation water samples analyzed were within the acceptable range of 6.5–8.5 for agricultural use. Fecal coliform levels were <1,000 MPN per 100 mL irrigation water and <1,000 MPN per g of compost. The vegetables produced by Agri-Hub small-scale farmers met the requirements for total coliforms of <200/g set by the South African Department of Health at the time of sampling. E. coli MPN values for irrigation water and vegetables were below the limit of detection. In addition, the farming practices of 73 farmers were assessed via a survey. The results revealed that more than 40% of farmers used microbiologically safe tap water for irrigation and that trained farmers have a significantly better understanding of the importance of production hygiene than untrained farmers. These results reiterate the importance of interventions that build capacity in the area of food safety and hygiene of small-scale farmers for market access of formal value chains.

Cytoprotective and antioxidant effects of the edible halophyte Sarcocornia perennis L. (swampfire) against lead-induced toxicity in renal cells

Lead (Pb) exposure is considered as a risk factor responsible for renal impairment in humans. On the other hand, the halophyte Sarcocornia perennis is a fresh vegetable crop suitable for leafy vegetable production. This study was designed to evaluate the in vitro protective activity of S. perennis against lead-induced damages in HEK293 kidney cells. Morphological and biochemical indicators were used to assess cytotoxicity and oxidative damages caused by Pb treatment on the cells. Our results showed that lead induced (1) a decrease in cell viability (MTT), (2) cell distortion and cohesion loss, (3) superoxide anion production and lipid peroxidation.Conversely, addition of S. perennis extract to the lead-containing medium alleviated every above syndrome. Thus, cell survival was increased and the production of reactive oxygen species caused by Pb treatment was inhibited. Taken together, our study revealed that S. perennis has potent cytoprotective effect against Pb-induced toxicity in HEK 293 cell. Such action would proceed through the decrease in ROS levels and resulting oxidative stress, which suggests a potential interest of this halophyte in the treatment of oxidative-stress related diseases.

Maximum Likelihood Estimates and Determinants of Technical Efficiency of Leafy Vegetable Producers in Akwa Ibom State, Nigeria

Leafy vegetables are important delicacies in the diet of most people in Nigeria and have played important role in helping to solve food security problems mainly in the rural areas. This study was carried out to determine the influence of some socio-economic and environmental factors on technical efficiency of leafy vegetable producers in Akwa Ibom State, Southern Nigeria. The results show that leafy vegetable production in the study area is female dominated. The Maximum Likelihood Estimates (MLEs) of the Cobb-Douglas stochastic production frontier function indicated that age of vegetable producers have a negative and significant influence on their technical efficiency, while, educational level, farming experience, farm size, household size and soil quality have positive and significant influence on their technical efficiency. The study recommends the formulation and implementation of policies that would encourage establishment of Adult and Continuing Education in the State, and adoption of sustainable systems of farming that will enhance good soil quality and environmental sustainability, with adequate supply of inputs to promote efficient production of vegetables in the area.

Economics of Leafy Vegetable Production

It is necessary to develop methods to increase profitability of leafy vegetable production because it is the most important factor dictating flow of capital. An economic analysis of leafy vegetable production in Osun State, Nigeria, was carried to determine profitability of production. The study examined socioeconomic characteristics of respondents and analyzed costs and returns to leafy vegetable production. A total of 60 respondents were interviewed. Primary data were collected with a questionnaire and analyzed using descriptive statistics and enterprise budgetary analyses. Mean age of respondents was 38 years and average household size was 5. The mode level of education was secondary. The mean years of experience was 11 and the mode farm size was between 0.01 and 0.4 ha. Gross margin and net profit were 91,161 and 82,441 (, naira, Nigerian currency, 157 = US$1), indicating that leafy vegetable production was profitable. Profitability, using profit margin analysis, was 62.8%, the benefit–cost ratio was 2.7, return per naira outlay was 1.7 and the operating expense ratio was 30.5%, indicating that there is room for improvement in leafy vegetable production.

淡路島三原平野における農業生産をめぐるネットワーク

This study reveals interactions between agricultural production and actor’s relations in Kamihata settlements in Minami-Awaji City, Mihara Plain. Farm management in farm households is examined to determine whether farm activities, such as lending equipment, supplying compost, and establishing delivery routines develop the relationships among farmers or between farmers and other stakeholders, while identifying the kind of relationships formed. Moreover, the contribution of multi-layered network formed through relations between and among such stakeholders is considered. The research method adopts social network analysis. This approach allows a quantitative stand in analyzing human relations based on the presence or strength of ties between nodes, the distance between such nodes, and the node parameters. Economic activity and social life are inseparable in rural areas and villages, and ties among farm households are characterized by various roles existing in a multilayered structure. This study focuses on the extent and width of social ties among certain nodes. Results show that in Mihara Plain, the “ three crop” rotation system―a combination of paddy rice, onions,and cabbages or paddy rice, lettuce, or Chinese cabbages―has been widely promoted. The study area practiced intensive farming. The production of leafy vegetables served as an economic activity that could augment the income of farm households. Farm management, as practiced by every farmer household, progressed within the range of social groups such as settlements and districts, and did not become completely independent albeit done individually. Various territorial relations became a conforming frame, as seen in the sharing of equipment and supplying of compost. The network was selectively formed according to the purpose. In addition to the abovementioned relations, networks based on the delivery of crops was observed. These networks extended in various ways, according to every farmer household's management policy, and had various influences on every farmer's management practices.