Greenhouse Vegetables Research Articles

Are microplastics correlated to phthalates in facility agriculture soil?

Intensive use of plastic films can induce contamination of microplastics (MPs) and phthalate esters (PAEs), but data on their relationship in agricultural soil has been scarce. This study investigated the occurrence of MPs and PAEs in Shouguang (SG) and Xuzhou (XZ), two typical facility agriculture areas in China with years of history of vegetable greenhouse plantation. Thirty-four soil samples covering greenhouse and non-greenhouse soils were collected. MPs were quantified using the laser direct infrared (LDIR) method to realize IR analysis for all the collected particles. The total MP and PAE was 380–3786 pieces/kg and 0.30–1.58 mg/kg, respectively. The MP content in greenhouse soil was significantly higher than that in non-greenhouse soil in both areas. However, this trend for PAEs was only found in XZ, but not in SG. A positive correlation was observed between MPs and PAEs in XZ but not in SG. Our results suggested that MP concentrations mainly depend on input, while the residue of PAEs in soil was a consequence of both input and removal. Even in the facility soil, MPs and PAEs may not always possess a definitive relationship, and other environmental factors must be considered to elucidate the relationship between them.

ЕФЕКТИВНІСТЬ ВИТРАТ І ЗАЛУЧЕННЯ ІНВЕСТИЦІЙ У РОСЛИННИЦТВІ

Сучасний стан фінансового забезпечення сільського господарства України свідчить про необхідність активізації інвестиційних процесів і підвищення ефективності вкладення коштів. Мета статті — презентувати результати оцінювання й аналізу відносної ефективності витрат на виробництво продукції рослинництва з використанням методу аналізу середовища функціонування, що дозволило виявити особливості використання інвестицій і розрахувати строк їхньої окупності. Ідентифіковано можливість скорочення прямих витрат на оплату праці й прямих матеріальних витрат під час виробництва продукції рослинництва. Установлено, що найбільший потенціал зменшення прямих витрат на оплату праці і прямих матеріальних витрат на виробництво характерний для дев’яти культур (жито, овес, гречка, зернові сушені, соя, ріпак, соняшник,картопля, овочі закритого ґрунту), оскільки показники менші за 0,5. Водночас потенціал із вирощування пшениці, проса, овочів відкритого ґрунту та ягідних культур використаний на 100 %. Потенціал збільшення обсягу реалізації продукції ягідних культур, гречки, насіння ріпаку й кользи, цукрового буряку фабричного становить 1, тобто використаний на 100 %, однак виробництво дев’яти культур має істотний нереалізований потенціал — більше ніж 50 % (потенціал збільшення обсягу реалізації продукції за наявних витрат перебуває в межах від 0 до 0,5). Прийнявши величину скорочення прямих матеріальних витрат як мету оптимізації показників розвитку рослинництва на найближчу перспективу, установлено, що дисконтований строк окупності інвестиції становить 15 років, що вимагає посилення ролі інвестицій у сільське господарство шляхом стимулювання праці найманих працівників.

Phosphorus Fractions Affected by Land Use Changes in Soil Profile on the Loess Soil

To evaluate the effect of land use changes on phosphorus pools and its accumulation in the soil profile on loess soils. This study applied a modified Hedley fractionation method to investigate soil P pools in 100-cm soil profile after conversion of wheat-maize (W-M) to greenhouse vegetable (GV) or kiwi orchard (kiwi). Land use changes from W-M to GV significantly increased total P stock by 82% at 0–100-cm soil profile. In particular, conversion from W-M to GV greatly increased easily available P at 0–80 cm by 11–291%, moderately available P at 0–60 cm by 83–253%, and non-available P at 0–40 cm depth by 42–214%, respectively. Conversion from W-M to kiwi also markedly raised total P stock by 15% at 0–100-cm soil profile, in which easily available P and moderately available P at 20 cm depth increased by 161% and 130%, and non-available P at 80–100-cm depth rose by 85.6%. Land use change also caused a shift in the distribution of P pools, i.e., percentages of easily available P rose by 10–13% at 0–80 cm under GV and by 10–15% under kiwi at 0–100 cm over the W-M. Correspondingly, ratios of moderately available P also increased by 7–8% at 20–60-cm depths and by 7–10% at 0–100-cm depths. By contrast, proportions of non-available P decreased. Our results indicate a huge amount of P accumulated into the soil profile, and its solubility also increased, especially under GV, which would have significant environmental consequences. Therefore, rational P management for cash crops should arouse the attentions in all sectors of the society.

Prevalence and risk factors for MSDs in vegetable greenhouse farmers: a cross-sectional survey from Shandong rural area, China.

Purpose: The aim of the research is a cross sectional survey on the prevalence of symptoms related to MSDs in vegetable greenhouse farmers from Shandong rural area and on the risk factors that may influence it. Methods: This cross-sectional survey was selected 249 farmers working in vegetable greenhouse from different districts of Shandong Province, China. The Questionnaire and the Rapid Upper Limb Assessment (RULA) technique were used to identify ergonomic risks. χ2 analysis was used to find the relationship between MSDs and various factors. Also, logistic regression methodology was applied to get the most influencing factor for MSDs. Results: The prevalence of MSDs in farmers working in vegetable greenhouse is 87.5%, and the top 3 prevalent areas of MSDs in various parts of the body are: lower back (47.4%), neck (33.3%), and shoulder (31.7%). The results of Logistic regression analysis showed that age, years working in vegetable greenhouses, keeping their backs in the same position for a long time, and working hours greater than 10 hours per day were the risk factors for MSDs in the farmers. The outcome of the RULA grand score had been found to be higher than 5 in the overwhelming majority of the farmers. Conclusions: All findings infer that each task of greenhouse vegetable growing inflicts different levels of disorder in a farmers’ musculoskeletal structure. Interventions should be increased and reduce the bad ergonomic load level as soon as possible, provided to reduce the impact of such disorders.

Using an Improved YOLOv4 Deep Learning Network for Accurate Detection of Whitefly and Thrips on Sticky Trap Images

HighlightsThe proposed method detected thrips and whitefly more accurately than previous methods.The proposed method demonstrated good robustness to illumination reflections and different pest densities.Small pest detection was improved by adding large-scale feature maps and more residual units to a shallow network.Machine vision and deep learning created an end-to-end model to detect small pests on sticky traps in field conditions.Abstract. Pest detection is the basis of precise control in vegetable greenhouses. To improve the detection accuracy and robustness for two common small pests (whitefly and thrips) in greenhouses, this study proposes a novel small object detection approach based on the YOLOv4 model. Yellow sticky trap (YST) images at the original resolution (2560 × 1920 pixels) were collected using pest monitoring equipment in a greenhouse. The images were then cropped and labeled to create sub-images (416 × 416 pixels) to construct an experimental dataset. The labeled images used in this study (900 training, 100 validation, and 200 test) are available for comparative studies. To enhance the model’s ability to detect small pests, the feature map at the 8-fold downsampling layer in the backbone network was merged with the feature map at the 4-fold downsampling layer to generate a new layer and output a feature map with a size of 104 × 104 pixels. Furthermore, the residual units in the first two residual blocks were enlarged by four times to extract more shallow image features and the location information of target pests to withstand image degradation in the field. The experimental results showed that the mean average precision (mAP) for detection of whitefly and thrips using the proposed approach was improved by 8.2% and 3.4% compared with the YOLOv3 and YOLOv4 models, respectively. The detection performance slightly decreased as the pest densities increased in the YST image, but the mAP value was still 92.7% in the high-density dataset, which indicates that the proposed model has good robustness over a range of pest densities. Compared with previous similar studies, the proposed method has better potential to monitor whitefly and thrips using YSTs in field conditions. Keywords: Deep learning, Greenhouse pest management, Image processing, Pest detection, Small object, YOLOv4.

Epidemiological Data of Work-Related Musculoskeletal Disorders - China, 2018-2020.

What is already known about this topic?In recent decades, work-related musculoskeletal disorders (WMSDs) have become increasingly prominent and have become an important issue that is of universal concern and an urgent need to be solved in all countries of the world.What is added by this report?The top three industries or occupational groups with the highest standardized prevalence rate of WMSDs were flight attendants, medical staff, and vegetable greenhouses in that order. Women workers were 1.5 times more likely to suffer from WMSDs than men workers.What are the implications for public health practice?This study has found the prevalence and distribution characteristics of WMSDs in key industries in China. It is urgent to draw up relevant measures to prevent and control occupational populations with WMSDs.

The modern pace of development and perspectives of horticulture in Azerbaijan

The Republic of Azerbaijan has all the conditions, both natural and socio-economic, for the development of horticulture. Over the last decade, the gross harvest of vegetables has been growing steadily. By 2018, it was 1522 thousand tons. The yield of vegetables has also grown in the indicated period from 14.7 to 21.9 t/ha. Vegetables occupy 4800 ha of a protected ground. The production of greenhouse vegetables targets the Russian market. The bottleneck of this sector is the breeding of vegetable seeds. This market, with a capacity of almost 20 million Euro, is occupied by foreign companies. At the same time, agricultural producers get help from the state in the form of subsidies, preferential credits, and full tax exemption. The research in the sector is also developing. We can note such possible developments as the renovation and outfitting of the Research Institute for Horticulture as well as the training of horticulturists in the Azerbaijan State Agricultural University. The further development of the sector continues in the way of the intensification and biologization of production, the improvement of the range and quality of products.

Optimization of productivity and quality of cucumber plants in protected ground

The paper studies the effect of growth stimulants on morphometric indicators of cucumber plant growth and development in the phase of intensive vegetation and transition to fruiting. The study was carried out at LLC Agricultural Enterprise “Teplitsy Belogorya” on the parthenocarpic hybrid of cucumber Tristan F1. Within the scientific and production experiment the grown cucumber plants on cotton-mineral cubes with drip watering were additionally vegetatively treated with a humic fertilizer solution and Azosol 36 microfertilizer. Phenological observations were carried out and morphometric parameters were determined: plant height, stem and leaf weight, leaf area, root system weight. Under the influence of treatments, the leaf area and weight of cucumber leaves increased by an average of 20 and 17%, respectively. It was established that vegetative treatment with the studied solutions allows partially controlling physiological processes and organogenesis of the greenhouse cucumber plant. The vegetative organs of the cucumber plant leaf, stem and root were found to exhibit different abilities to accumulate chemical elements within the two experiments. The series of element distribution in the natural substance of the plant vegetative organs are shown (in a decreasing amount, total nitrogen, phosphorus, potassium for a series: leaf – stem – root; calcium, magnesium, zinc, iron, manganese and copper for the series: root – leaf – stem). The use of the studied fertilizers increased the commercial quality of cucumber fruits. Button contained a higher amount of total sugar and vitamin C, were environmentally safe in terms of the content of nitrates and heavy metals (cadmium, lead, arsenic, mercury). The optimization of productivity and quality improvement of cucumber plants using biological humic fertilizer and chelate microfertilizer increased the average yield by 5.5% and the profitability of ecologically safe greenhouse vegetables by 3.3%.

Heavy metal pollution characteristics and assessment of environmental quality and safety of facility agriculture soil in Shouguang

Taking Shouguang Facility agriculture in Weifang City as the research object, heavy metals and other pollutants in new and old facility agriculture soil were investigated and analyzed from 2017 to 2019. The content of heavy metals in soil was analyzed, and the environmental quality of heavy metals was evaluated by single-factor pollution index method and Nemerow index method. The correlation between heavy metal content in surface soil and cultivation years, vertical distribution of heavy metal content in soil, frequency distribution of heavy metal in surface soil, and correlation between heavy metals in surface soil and soil nutrients were analyzed. The results showed that the average contents of the eight heavy metals were Cd 0.23 mg•kg−1, Hg 0.05 mg•kg−1, As 8.09 mg•kg−1, Pb 23.31 mg•kg−1, Cr 70.81 mg•kg−1, Cu 38.54 mg•kg−1, Ni 25.87 mg•kg−1 and Zn 147.52 mg•kg−1. Aside from Pb and Ni, the average content of all other heavy metals in the surface soil of facility agriculture was higher than the average of the control and the geochemical background level of soil in Weifang. Compared with the Environmental Quality Evaluation Standard for Farmland of Greenhouse Vegetables Production (HJ333-2006) and the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (trial) (GB15618-2018), the average content of heavy metals met the standards, with Cd, Hg and Zn content in some samples exceeding the standards. Most surface soil environmental quality is clean or relatively clean, but there is also part of the soil has reached the level of mild or moderate pollution. The content of heavy metals in the soil of the old facility agriculture (cultivation years > 10) was higher than that of the new facility agriculture (cultivation years ≤ 10), and the content of heavy metals in the surface soil (0∼20cm) was higher than that in the deep soil. The quality distribution of heavy metals in the surface soil is affected by exogenous heavy metals, among which Hg and Cd have the largest skewness coefficient and are most affected by exogenous. There was significant positive correlation between heavy metals in surface soil and available phosphorus, hydrolytic nitrogen, available potassium and organic matter. The results indicated that the accumulation of heavy metals in soil was related to the application of organic fertilizer, phosphate fertilizer and compound fertilizer.

The Global Blue Water Use for the Dutch Diet and Associated Environmental Impact on Water Scarcity

Agriculture is responsible for around 70% of global water withdrawal, making it the largest consumer of freshwater. Globally, freshwater is a scarce resource, and there is increasing risk that current water use is crossing the planetary boundary, meaning that humanity is using more freshwater than nature can replenish. Beside the amount of water used for the production of food, also the location of water use is of importance to identify local water scarcity. In this study we determined and analyzed the blue water use for the Dutch diet. Also, we provide an indication of the the spatial distribution in water use, related to water scarcity. The blue water use per person for the average diet of the Dutch adult population aged 19-79 years as calculated in this study was 160 l/day (=57 m³/year) for men and 153 l/day (=56 m³/year) for women. Non-alcoholic beverages were the most important contributor to water use for the diet of men as well as women. Fruits were the second most important contributor to water use for the diet of women (particularly oranges, tangerines, strawberries and bananas), and the third most important for men. Meat was the second most important contributor for men (particularly chicken fillet and beef meat) and the third for women. About one third of the blue water use for the Dutch diet takes place in countries where 30 to 70 times less available water remaining per area than the world average. This means that water scarcity is relatively high in those countries compared to the world’s average. The main countries of origin of the water used for food production for the Dutch population we identified were Spain, the Netherlands itself, South Africa, Chile, India and USA. Products with ingredients from Spain are several types of greenhouse vegetables, citrus fruits and juices. To lower the environmental impact related to blue water use, for the Dutch situation we conclude that beside reducing meat and dairy consumption, consuming more Dutch fruits like apples and pears, and reducing imports of fruits and nuts from e.g. Spain, Chile and USA, are relatively easy changes that will have a positive effect on the global water scarcity impact. Also, reducing the consumption of non-alcoholic beverages like coffee, soft drinks and juices, and increasing the use of tap water, is recommended to lower the Dutch blue water use within a healthy diet.

Comprehensive assessments of soil fertility and environmental quality in plastic greenhouse production systems

The increasing demand of fruits and vegetables has resulted in the rapid growth of plastic greenhouse production (PGP) systems worldwide. A comprehensive assessment method considering both soil fertility and environmental safety is necessary for the sustainable development of PGP systems. A total of 92 vegetable greenhouses in Jingyang County and 28 fruit greenhouses in Dali County in Shaanxi Province, China, were selected for comparing the changes of soil quality under two cultivation patterns. The soil comprehensive quality index (SQI) in Jingyang (0.53) was significantly higher than that in Dali (0.46) (p < 0.05). A significant correlation was found between the SQI and the soil fertility index (SFI) (p < 0.01), suggesting that the SQI was mainly dependent on the soil fertility level in greenhouses. The primary limiting factors of the SFI in PGP in Jingyang and Dali were low soil organic matter content (19.57 g kg−1) and high electrical conductivity (1303 μS cm−1), respectively, indicating that soil in greenhouses in Jingyang and Dali might experience nutrient deficiencies and soil salinity accumulation problems, respectively. Cd and Hg were main limiting factors of soil environmental index (SEI), especially Hg. The SEI in Dali (0.74) was significantly lower than that in Jingyang (0.81) due to differences in the geo-accumulation indexes of heavy metals in the topsoil in greenhouses. Considering that no significant difference was found in the SFI between two study areas, the SEI is likely responsible for the regional differences in the SQI in PGP. The negative correlation of the SEI with the cultivation ages of plasticulture indicated that heavy metal accumulation problems would be the primary limiting factor of the SQI in the future if greenhouses cannot be managed appropriately. Our study provides data support for soil quality management in PGP systems.

Enhanced N2O emission rate in field soil undergoing conventional intensive fertilization is attributed to the shifts of denitrifying guilds

The emission of greenhouse gas N2O in agricultural soil is modulated by N fertilization that could be converted to N2O by denitrifiers under anaerobic condition. Nevertheless, the effect of denitrifiers on N2O emission has not been thoroughly elucidated. In this study, we explored the denitrifying gas kinetics, nitrate content, transcribed denitrifying functional genes (narG, nirS, nirK, and nosZ), and the active bacteria during anaerobic incubation of soils with conventional intensive N fertilization (CNS) and reduced N fertilization (RNS), both sampled from a vegetable greenhouse experimental site. The CNS sample showed significantly higher N2O emission rates relative to the RNS sample. However, the difference in N2O emission between the soils was neither because of the cumulative nitrate content nor the quantity of denitrifying gene transcripts. The distinct fertilization regimes shaped the significantly different bacterial communities in these soils. The absolute abundance of bacteria that produce N2O but lack the nosZ gene for N2O reduction (for example, the dominant Kaistobacter) was higher in CNS than in RNS. Meanwhile, the abundance of two operational taxonomy units (OTUs), namely Rhodanobacter, belonging to the most abundant genus in denitrifying guilds, was strongly enriched in CNS and showed significant positive correlation with N2O/(N2O + N2). The predominance of these bacterial OTUs in the CNS denitrifying guild strongly suggested that high N2O emission from the soil with long-term conventional intensive fertilization might be primarily attributed to the reshaping of distinct denitrifying guilds in their bacterial communities.

Research on the Treatment of Soil Leachate by Using Microalgae

In order to remove and recover nitrogen and phosphorus of water from soil surface runoff, the combination method of cultivation and harvesting of microalgae was used in this research. Microalgae was cultured in the leachate of soil which was collected from vegetable greenhouse; culture solution was sampled and detected at different intervals. The results showed that leachate contained nutrients which could meet the needs of algal growth, the algal density increased in line with increase of culture time; pH of culture solution was alkaline and increased fast in the first 5 days; total and soluble phosphorus, total nitrogen and nitrate decreased fast in the first 5 days which showed assimilation of microalgae could remove phosphorus and nitrogen in the leachate.

Biochemical, Physiological, and Productive Response of Greenhouse Vegetables to Suboptimal Growth Environment Induced by Insect Nets.

Simple SummaryGlobal warming jeopardizes agriculture, which must satisfy the demands of the world’s expanding population for both staple and high-quality products while ensuring increased sustainability. Environmental and regulatory pressure has prompted farmers to convert their production strategies towards sustainable agriculture systems, by introducing for instance, integrated pest management strategies. Insect nets are a suitable tool for pest control but require careful assessment of their effects on the generated microclimate. The low porosity, mandatory for proper exclusion, results in suboptimal airflow and in temperature rise with detrimental effects on crop production and quality. The biochemical and morpho-physiological changes induced by high-temperature impact vegetable crop performance and product quality in advanced growing systems, and also represent a challenge for the most impoverished developing countries of the world, which rely on local horticultural products as a key source of dietary diversity.Environmental pressure poses a major challenge to the agricultural sector, which requires the development of cultivation techniques that can effectively reduce the impact of abiotic stress affecting crop yield and quality (e.g., thermal stress, wind, and hail) and of biotic factors, such as insect pests. The increased consumer interest in premium-quality vegetables requires the implementation of sustainable integrated pest management (IPM) strategies towards an ever-increasing insect pressure, also boosted by cultivation under protected structures. In this respect, insect nets represent an excellent, eco-friendly solution. This review aims to provide an integrative investigation of the effects of the insect screens in agriculture. Attention is dedicated to the impact on growth, yield, and quality of vegetables, focusing on the physiological and biochemical mechanisms of response to heat stress induced by insect screens. The performance of insect nets depends on many factors—foremost, on the screen mesh, with finer mesh being more effective as a barrier. However, finer mesh nets impose high-pressure drops and restrict airflow by reducing ventilation, which can result in a detrimental effect on crop growth and yield due to high temperatures. The predicted outcomes are wide ranging, because heat stress can impact (i) plant morpho-physiological attributes; (ii) biochemical and molecular properties through changes in the primary and secondary metabolisms; (iii) enzymatic activity, chloroplast proteins, and photosynthetic and respiratory processes; (iv) flowering and fruit settings; (v) the accumulation of reactive oxygen species (ROSs); and (vi) the biosynthesis of secondary biomolecules endowed with antioxidant capacity.

Quantitative analysis of the regulatory gene HSF1 of Bemisia tabaci under different temperatures

Bemisia tabaci (Gennadius) is one of the most important pests in tropical, subtropical and adjacent temperate regions. B. tabaci is a major agricultural pest that is closely watched worldwide. With the widespread application of vegetable greenhouse planting patterns and frequent vegetable and flower transfers, more favorable conditions were created for the occurrence and spread of B. tabaci, making it the major pest in China's agricultural production.&#x0D; The ability of B-biotype to adapt for new environments is closely related to its tolerance to temperature. Heat shock proteins (HSP s) are the group of proteins produced by cells under the induction of stressors, especially environmental high temperature. Heat shock proteins play an important role in the adaptability of organisms to the environment. This experiment mainly was studied from the heat shock protein of B. tabaci and its regulatory factors (Heat shock factor 1, hsf1). Meanwhile, fluorescence quantitative technology was used to observe the expression of this regulatory factor under different temperature conditions. It is speculated that the HSPs regulatory factor hsf1 is B-biotype B. tabaci and it can induce protection against high temperature stress.

Atmospheric phthalate pollution in plastic agricultural greenhouses in Shaanxi Province, China.

Phthalate pollution in soil and vegetables in plastic agricultural greenhouses has attracted wide concern. Investigating airborne phthalates in this environment can improve understanding of air-soil or air-vegetable phthalate migration. However, studies of phthalates in plastic agricultural greenhouse air are rare. To fill this gap, 25 gas-phase and 23 particle-phase samples were collected from 12 typical plastic greenhouses in Shaanxi. 16 types of phthalates were measured by a gas chromatography-mass spectrometry system (GC-MS) to analyse their pollution features and variations. Results showed that in the air of the plastic greenhouses, the median concentration of the sum of sixteen type phthalates (∑16 phthalates) was 5305ngm-3, with 5th-95th value of 1214-9616ngm-3. Phthalates in gas-phase samples were over 100 times higher than the levels in particle-phase samples. Air phthalate concentrations in the plastic greenhouses were higher than those in the control groups (P<0.05). Air bis (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) accounted for 66.9% and 29.3% of total ∑16 phthalate concentrations, respectively. Air phthalate concentrations in the plastic greenhouses in winter were 1.1-5.3 times higher than the levels in summer respectively (P<0.05). Gas-particle partition coefficients (KP) values of DEHP in summer (median of 1.52×10-4m3μg-1) were higher than KP values of DnBP in summer (0.60×10-4m3μg-1). Log-transformed KP values of DnBP and DEHP were linear correlated to the reciprocal of air temperatures, respectively (P<0.05).

GREENRESILIENT – applying agroecology to organic greenhouse production

Some organic greenhouse production systems are very intensive with potentially negative effects on the public trust on organic products as a whole. In this context, the year-round production of high quality and tasty vegetables in unheated and low-energy greenhouses or polytunnels, using resilient, sustainable and local systems, is a challenge, especially in areas with long winters and low light, low temperature conditions. The CORE Organic Cofund transnational project titled “Organic and biodynamic vegetable production in low-energy GREENhouses NDASH sustainable, RESILIENT and innovative food production systems” (GREENRESILIENT) has taken up the challenge and aims to demonstrate that an agroecological approach to greenhouse production is feasible and allows the establishment of robust agroecosystems in different European areas. The use of agroecological practices in organic greenhouse production systems is an innovative approach and a team of scientists with multidisciplinary competences (agronomy, agroecology, soil chemistry, entomology, plant pathology, weed science, life cycle analysis) from 12 research centres in eight European countries are involved. Research activities are carried out in five experimental sites (two in Mediterranean countries and three in central and northern countries), comparing innovative systems in unheated or frost protected conditions to a standard organic system specific for each experimental site. Results obtained will be used for actors' involvement (farmers, consumers and policy makers) and sustainability assessment.

Testing the effect of new biopesticides on soilborne pathogens of vegetable diseases using DNA markers

In protected ground, vegetables are exposed to various pests and pathogens of viral, bacterial or fungal diseases. Growing vegetables indoors requires the elimination of all chemical treatments and control over pathogens and pests. In this regard, the application of sensitive methods based on molecular markers in the diagnostics of pathogens is highly relevant. In this work, polymerase chain reaction was used to identify the most common diseases of tomato (Xanthomonas euvesicatoria), cucumber (Ascochyta cucumis) and potato (Clavibacter michiganensis subsp. Sepedonicus) plants. It was established that early diagnosis of vegetable diseases using polymerase chain reaction allows rapid detection of trace amounts of pathogenic microorganisms thus facilitating selection of effective fungicidal preparations. The creation of biological protection for vegetable crops is relevant considering their nutritional importance. New biological methods for protecting vegetables in greenhouses were tested. Thus, the fungicidal effect of the authors’ patented preparation developed for pre-sowing treatment of vegetable seeds in protected ground on the pathogens of tomato black bacterial spot (Xanthomonas euvesicatoria) and cucumber stem hypertrophy (Ascochyta cucumis) was confirmed. Another preparation patented as a means of pre-sowing treatment of pea seeds demonstrated fungicidal action against the development of Phytophthora infectants on potato plants. It was observed that these preparations are effective at concentrations of 10-4 % for soaking seeds and double treatment of plants during the flowering period.

Double hurdle approach to consumer awareness, perception of, and willingness to pay for greenhouse vegetables

ABSTRACT Understanding awareness, perception of, and willingness to pay from the consumer’s perspective could increase acceptance of greenhouse grown vegetables. Multistage sampling was used to select 120 respondents consuming greenhouse vegetables. Data were collected with a structured questionnaire, analyzed with descriptive statistics, and a double hurdle regression model. Most respondents were male with mean age, household size and monthly income of 38 years, 5 persons and ₦115,566.7, respectively. The majority of respondents were aware of, and had favorable perceptions of, greenhouse vegetables [tomato (Solanum lycopersicum L.), cucumber (Cucumis sativus L.), and bell pepper (Capsicum annuum L.)], but were not willing to pay the additional cost. The mean amount respondents were willing to pay∙kg−1 of tomato; cucumber and bell pepper were ₦799.17, ₦776.67, and ₦742.92, respectively, ₦ is the Naira, Nigerian currency, 1$US = 365₦. Increased awareness and income could increase respondent willingness to pay for greenhouse vegetables while increased number of dependent individuals reduces it. Greenhouse vegetables are luxury goods, increasing income could increase respondent overall acceptance. Information leading to implementing pricing tactics and promotion could help improve overall respondent acceptance of greenhouse grown vegetables.

Assessing impacts of nitrogen management on nitrous oxide emissions and nitrate leaching from greenhouse vegetable systems using a biogeochemical model

Greenhouse vegetable (GV) fields with intensive nitrogen application and frequent flood irrigation may substantially contribute to reactive nitrogen (Nr) losses, such as nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. In this study, we applied a biogeochemical model, Denitrification-Decomposition (DNDC), to assess impacts of N management on vegetable yields, N2O emissions, and NO3−-N leaching from GV systems. The model was evaluated using multi-year (2011–2013) field measurements of vegetable yields, N2O emissions, and NO3−-N concentrations in the surface soil layer and soil leachate under three treatments with different N management. The model evaluations demonstrated that the simulations of the vegetable yields and seasonal cumulative N2O emissions were consistent with the corresponding observations after calibration. In addition, DNDC generally captured the seasonal variations of the N2O fluxes and NO3−-N concentrations in the surface soil layer and the seasonal patterns and magnitudes of the measured NO3−-N concentrations in soil leachate in 2011. We then assessed impacts on the vegetable yields, N2O emissions, and NO3−-N leaching of different N management practices by conducting simulations under scenarios with changes in rate of the applied N-fertilizers and the application of nitrification inhibitor (NI). The results suggested that 1) the increasing of organic or synthetic N application rate generally increased the N2O emissions and NO3−-N leaching, but did not persistently increase the vegetable yields, 2) urea N application could induce more N2O emissions and NO3−-N leaching in comparison with organic N amendment, and 3) the NI application could decrease the N2O emissions and NO3−-N leaching while maintaining the vegetable yields at the GV fields. The optimum management practice identified in this study was applying organic manure at a rate of 320 kg N ha−1 four season−1 and urea at a rate of 334 kg N ha−1 four season−1, combined with the NI application. The optimum management practice reduced the rates of organic manure (1600 kg N ha−1 four season−1) and urea (1670 kg N ha−1 four season−1) under the farm's conventional practice by 80%. This practice maintained or slightly increased the yields and mitigated the N2O emissions and NO3−-N leaching by 81% to 90% and 92% to 95%, respectively, among different vegetable growing seasons.