Greenhouse Cucumber Research Articles

The Variation of Soil Phosphorus Fractions and Microbial Community Composition under Consecutive Cucumber Cropping in a Greenhouse

The distribution of phosphorus (P) fractions in soil plays a decisive role in soil P bioavailability; however, the characteristics of soil P fractions under consecutive cropping in a solar greenhouse remain unclear. To evaluate the effects of the long-term successive vegetable cropping on soil P fractions and the microbial community composition in greenhouse soil, a continuous long-term cropping experiment was conducted using cucumber (Cucumis sativus L.) in a solar greenhouse starting from 2006 to 2018. Soil P fractions and the microbial community composition were determined using the Hedley continuous extraction method and the phospholipid fatty acid (PLFA) method, respectively, in the 1st, 9th, 13th, and 21st rounds of cultivation. The soil total phosphorus (TP) content increased from 0.90 g·kg−1 in the 1st round to 3.07 g·kg−1 in the 21st round of cucumber cultivation. With an increase in continuous cropping rounds, soil available phosphorus (AP) increased and the phosphorus activation coefficient (PAC) decreased, with no significant difference between the 13th and 21st rounds. After 21 rounds of continuous cropping, the soil organic matter (SOM) content was 16.34 g·kg−1, 1.42 times that of the 1st round. The abundance of soil bacteria, actinomycetes, Gram-negative bacteria (G−), Gram-positive bacteria (G+), and total PLFAs initially increased with continuous cropping rounds, but then decreased significantly, and the ratios of fungi:bacteria (F/B) and G+/G− bacteria also increased significantly with continuous cropping rounds. The contents of soil labile P, moderately labile P, and non-labile P increased significantly over 21 continuous cropping rounds. Together, these results demonstrate that long-term continuous cropping can directly lead to the accumulation of P fractions, but it can also affect the abundance of actinomycetes through SOM enrichment, which indirectly leads to the accumulation of non-labile P. This study provides a theoretical basis for future soil P fertilizer management and vegetable production sustainability.

Dissipation, residue, stereoselectivity and dietary risk assessment of penthiopyrad and metabolite PAM on cucumber and tomato in greenhouse and field

Penthiopyrad is a broad-spectrum fungicide with wide application in agriculture with preferential degradation of the S (+)-stereoisomer in soil. An understanding of the stereoselective fate of penthiopyrad is crucial for accurate food safety risk assessment. In this study, the dissipation, distribution, and dietary intake risk of penthiopyrad and its main metabolite (PAM) was conducted in cucumber and tomato samples under greenhouse and open field conditions. The half-lives of penthiopyrad in cucumber and tomato samples were < 8 days and the dissipation rates were higher in the open field than in the greenhouse. Due to the enantiomeric fraction data > 0.5, S (+)-stereoisomer dissipated slightly faster than R-(−)-stereoisomer. The residues of total penthiopyrad (sum of rac-penthiopyrad and PAM) were lower than the maximum residue limits in cucumber and tomato samples (risk quotients ≪ 100%). Therefore, the recommended penthiopyrad spraying method does not threaten vegetable cultivations and has negligible dietary intake risk.

ADDLight: An Energy-Saving Adder Neural Network for Cucumber Disease Classification

It is an urgent task to improve the applicability of the cucumber disease classification model in greenhouse edge-intelligent devices. The energy consumption of disease diagnosis models designed based on deep learning methods is a key factor affecting its applicability. Based on this motivation, two methods of reducing the model’s calculation amount and changing the calculation method of feature extraction were used in this study to reduce the model’s calculation energy consumption, thereby prolonging the working time of greenhouse edge devices deployed with disease models. First, a cucumber disease dataset with complex backgrounds is constructed in this study. Second, the random data enhancement method is used to enhance data during model training. Third, the conventional feature extraction module, depthwise separable feature extraction module, and the squeeze-and-excitation module are the main modules for constructing the classification model. In addition, the strategies of channel expansion and = shortcut connection are used to further improve the model’s classification accuracy. Finally, the additive feature extraction method is used to reconstruct the proposed model. The experimental results show that the computational energy consumption of the adder cucumber disease classification model is reduced by 96.1% compared with the convolutional neural network of the same structure. In addition, the model size is only 0.479 MB, the calculation amount is 0.03 GFLOPs, and the classification accuracy of cucumber disease images with complex backgrounds is 89.1%. All results prove that our model has high applicability in cucumber greenhouse intelligent equipment.

Energy-economic-environmental cycle evaluation comparing two polyethylene and polycarbonate plastic greenhouses in cucumber production (from production to packaging and distribution)

Excessive consumption and improper management of inputs would lead to environmental damages, as well as decreased economic benefits. Thus, a thorough examination of the entire production process from the viewpoint of energy flow, economic profit, and environmental effects can identify hotspots and facilitate input management. Accordingly, in the current investigation, energy, economic and environmental aspects of greenhouse cucumber production systems were measured by life cycle assessment (LCA) technique and cumulative exergy demand (CExD) analysis by considering different greenhouse structures. Furthermore, the data envelopment analysis (DEA) approach was used to determine the efficiency of manufacturing units and optimal consumption pattern. The information required was acquired through interviews and questionnaires with 35 greenhouse owners, and consultation with greenhouse enterprises in the Khuzestan province of Iran. Based on the findings, energy consumed was 6626.45 MJton−1 in Sc1, and 6410.32 MJton−1 in Sc 3. The findings of benchmarking revealed that boosting the efficiency of the crop production process can lower input energy by 14.80%. The energy consumption for the construction of the first and second type of greenhouses was calculated to be 14,811.13 and 17,541.73 MJ (1000 m2)−1, respectively. With regard to the production variable costs, chemical fertilizers and labor had the largest contributions to the total expenses, at 7.6 (15.41%) and 7.87 $tonne−1(15.94%), respectively. In the evaluation of the energy and economic indicators, the combined indicator of Energy Intensiveness for the first and second types of greenhouse systems was found to be 80.26 and 77.07 MJ$−1, respectively, indicating higher energy-economic productivity of the first type of system. Based on LCA results, direct emissions due to input consumption (air: carbon dioxide (CO2), and nitrogen oxides (NOx); soil: mercury (Hg), copper (Cu), and lead (Pb)), and indirect emissions induced by chemical fertilizers, greenhouse structures, and chemical pesticides production are the environmental hotspots.

Test results of insecticides from the chemical class of anthranyldiamides on cucumbers in greenhouse

Relevance. The adaptive-integrated plant protection system is the basis of biologized protective measures against harmful organisms. This system provides for careful treatment of natural resources, prevents contamination of soil and water with pesticides and agrochemicals. In recent years, legislation and sanitary regulations have increasingly tightened the regulations governing the use of pesticides in crop production. Organic farming is becoming increasingly common. Leading global chemical companies are expanding their research on the biology of manufactured plant protection products: they give them a selective character, reduce the period of their inactivation, respectively, the waiting period. FMC manufactures and supplies to Russia new generation insecticides Verimark® and Benevia® from the chemical class of diamides compatible with the biomethode and having a short waiting time.Methods. In 2020-2021, in the greenhouse complex of the FSVC, an assessment of the biological effectiveness of the insecticides Verimark® and Benevia® on cucumber culture has been carried out. Verimark® was applied by shedding seedlings under the root and applying through a drip system, Benevia® was introduced by ground spraying of vegetating plants.Results. The most problematic cucumber pests in greenhouse are tobacco trips (Thrips tabaci) and greenhouse whitefly (Trialeurodes vaporarium). As a result of successive additions of the Verimark® (for the root) and Benevia® (for the leaves), the number of tobacco thrips was reduced by 90,8-98,9%. Spraying the plants with Benevia® in admixture with Codacide oil also provided a high positive effect against the greenhouse whitefly. Already on the third day, the number of pests decreased by 90,3%. Protective measures made it possible to increase crop yield by 26.3% in the first turnover and 28.3% in the second. The highest rates of biological efficacy were observed in the use of preparations before the start of pest settlement, which is fully supported by the recommendations of the manufacturer.

Exposure to dust, endotoxins and microbes in Finnish vegetable greenhouses.

In Finland and other northern countries, vegetable greenhouse workers are exposed to airborne dust and microbes all year round. The aim of the study was to assess respiratory exposure to dust, endotoxins and microbes, and to identify the risk phases of respiratory and skin exposure to promote safe working methods. Work in greenhouses was observed and recorded in a structured form. 23 personal samples and eight stationary samples of dust, endotoxins and viable microbes were collected from eight tomato or cucumber greenhouses in Finland. Dust samples were analysed gravimetrically. Endotoxins were analysed on filters by chromogenic Limulus amoebocyte lysate assay. Microbes were collected on filters, incubated and counted in three different culture media. Eight additional stationary samples of microbes were collected on a six-phase impactor. The greenhouses were generally clean and well organised, but skin protection was deficient. The median of personal dust exposure was 0.24 mg/m3: 0.21 mg/m3 in the tomatohouses and 0.62 mg/m3 in the cucumber greenhouses. The mean level of bacteria in the tomato houses was 2.7 × 103 and in the cucumber houses 1.6×104. Those of fungi were 3.6 × 105 and 1.7 × 105 on Hagem and 8.1 × 105 and 1.9 × 105 on DG-18, respectively. The microbes made up about 1/10 of these values in the stationary samples. Very low concentrations of endotoxins were found in 5/23 air samples. The clean appearance of the greenhouses was reflected in the low to moderate levels of dust. Risk phases of high exposure, such as lifting leaf debris, were identified. The microbe species were typical of this climate, and their levels were comparable to other greenhouse studies, but lower than in farming. Prevention among the foreign workforce is challenging due to the lack of a common language.

Relationship between accumulation of autotoxins and soil fertility factors under long-term continuous cropping of cucumber in solar greenhouse

In this study, we investigated the effects of long-term continuous cucumber cropping on phenolic acids in rhizosphere soil, as well as their link to soil chemical characteristics, enzyme activities, and microbiological activities, using rhizosphere soil from the 2nd, 6th, 10th, 14th, 18th, 20th, 24th, and 26th round of cucumber cultivation in solar greenhouse. The results showed that contents of phenolic acids increased significantly with increasing continuous cropping rounds. The increase amount per round of total phenolic acid was significantly higher in the early stage (0-2 rounds) and late stage (20-26 rounds) than middle stage (10-14 rounds) of continuous cropping. Soil nutrient contents were enriched, while invertase enzyme activity and microbial activities were decreased. Redundancy analysis showed that organic matter, total phosphorus, total nitrogen, available nitrogen, microbial biomass carbon and microbial metabolic entropy were main soil fertility factors correlating with the accumulation of phenolic acids. Results of structural equation model showed that soil phosphorus enrichment directly led to the accumulation of phenolic acids, and that nitrogen enrichment indirectly facilitated the accumulation of phenolic acids by altering the activity of microorganisms. As a result, proper nitrogen and phosphorus fertilizers application would reduce the accumulation of phenolic acids and alleviate the cucumber continuous cropping obstacles.

Humic substances suppress Fusarium oxysporum by regulating soil microbial community in the rhizosphere of cucumber (Cucumis sativus L.)

Fusarium wilt causes severe yield loss in greenhouse cucumbers. Humic substances refer to organic amendments typically applied in the soil to suppress pathogens and promote vegetable growth. The present study evaluated the effects of two humic substances (humic acid (HA)) from weathered coal and sodium humate from peat (HN) on the relative abundance of Fusarium oxysporum (F. oxysporum) and the greenhouse cucumber growth. HA and HN showed different chemical structures as per the Fourier transform infrared spectroscopy. HA and HN had different impacts on soil bacterial and fungal community compositions as well as on their network topological patterns. Specifically, both HA and HN increased the relative abundance of Firmicutes, Planctomycetes and Chloroflexi. HA increased the bacterial chao1 index and the observed_OTUs, while HN improved both the bacterial and fungal alpha-diversities. Both HA and the HN also increased the network interactions, as well as the clustering coefficients (21.2%–21.5%), degrees (387%–554%) and densities (300%–467%) compared to the unamended control. The structural equation model indicated that the HA and HN demonstrate positive correlations with the bacterial and fungal community structure and density; besides, the fungal community structure was negatively correlated with network density. The latter showed a negative correlation with the disease index. Hence, HA and the HN increase the fungal network complexity of the rhizosphere soil and downgrade the network density and subsequently the disease index; as a result, the aboveground biomass of the greenhouse cucumbers increases. Overall, this study demonstrates the link between humic substances and microbial community structures and highlights the significance of network topological patterns in suppressing Fusarium wilt disease and promoting cucumber growth.

Effect of Foliar Application of Silicon and Salicylic Acid on Regulation of Yield and Nutritional Responses of Greenhouse Cucumber Under High Temperature

Effect of Foliar Application of Silicon and Salicylic Acid on Regulation of Yield and Nutritional Responses of Greenhouse Cucumber Under High Temperature

Combined health risk assessment of organophosphates pesticide residues in greenhouse cucumber in the Northwestern of Iran based on Monte Carlo Simulations

ABSTRACT The samples of greenhouse cucumbers were collected from the Central Fruit and Vegetable Market of Tabriz between June and December 2017. In the twenty-four cucumber samples (unwashed, washed, peeled), the residue of 18 organophosphates pesticides (OPPs) was analyzed using gas chromatography-mass spectrometry (GC-MS) following the modified QuEChERS method (quick, easy, cheap, effective, rugged and safe). Chronic non-carcinogenic risk assessment from pesticide residues in the samples was also performed for age groups of adults (women and men) and children using the Monte Carlo Simulation (MCS). Amongst the eighteen studied pesticides, eight pesticides including dimethoate, diazinon, methyl parathion, fenitrothion, chlorpyrifos, profenofos, ethion, and azinphos-methyl were detected. Pesticide residues were detected in 100% of unwashed, washed and peeled samples in the range of 0.08 to 0.37 mg.kg-1, 0.03 to 0.17 mg.kg-1 and 0.01 to 0.08 mg.kg-1, respectively. The maximum and minimum values were found for diazinon pesticides with 0.37 mg.kg-1 and profenofos and fenitrothion with 0.01 mg.kg-1. 100 % of samples contained at least three pesticide residues (dimethoate, diazinon, and methyl parathion), while 87.5% of the samples contained more pesticides residues. The residues of dimethoate, diazinon, and methyl parathion were above Maximum Residue Limits (MRL) in 100%, 83.33%, and 66.66% of samples, respectively. The identified residues were more than the EU MRLs and the IR MRLs in 100% and 95.83% samples, respectively. The mean reduction of pesticide residues in the washed and peeled samples was in the range of 37.74 to 56.52% and 66.66 to 92.30%, respectively. According to the performed risk assessment, there is no significant non-carcinogenic health risk due to the consumption of cucumber for the age group of adults. Hence, there is a considerable non-carcinogenic health risk to children due to the consumption of unwashed (HI = 2.22) and water-washed (HI = 1.36) greenhouse cucumbers.

Inoculation of cucumber plants with Beauveria bassiana enhances resistance to Aphis gossypii (Hemiptera: Aphididae) and increases aphid susceptibility to pirimicarb

The entomopathogen Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) can colonize plants endophytically and stimulate the production of secondary plant metabolites with anti-herbivore activities. We assayed the topical virulence of B. bassiana to Aphis gossypii Glover (Hemiptera: Aphididae), the effects of cucumber inoculation with this fungus on plant metabolites, and the physiological consequences for aphids that fed on these plants. Assays were conducted with both the commercial formulation of B. bassiana, 'Naturalis&#174;-L', at the recommended concentration of 1.5 ml / L (yielding a spore concentration of 2.3 × 107 CFU per ml), and with a similar concentration of the isolated fungal strain. Topical application of 0.03 ml of solution per cm2, or 1 × 103 CFU, caused 100% mortality to A. gossypii adults after seven days, whether Naturalis&#174;-L or the isolate alone was used. The fungus grew endophytically into foliage when sprayed on cucumbers at the 2-leaf stage and concentrations of alkaloids, flavonoids, phenols, hydrogen peroxide, and total chlorophyll were higher than in control plants 28 days after inoculation. Malondialdehyde content, plant growth, and total yield were unaffected by B. bassiana inoculation. Aphids fed on B. bassiana-inoculated plants for 24 h had reduced activities of detoxifying enzymes (glutathione-S-transferase, carboxylesterase, and acetylcholinesterase) compared to controls. Activities of digestive enzymes, (lipase, &#945;-amylase, &#945;-glucosidase, and aminopeptidase) were reduced in aphids from inoculated plants, which exhibited higher activities of superoxide dismutase, ascorbate peroxidase, and phenoloxidase, but lower catalase activity. Energy reserves (lipids, protein, and glycogen) were lower in aphids from inoculated plants, and they exhibited reduced fecundity, longevity, and reproductive periods, and a 50% reduction in the LC50 of pirimicarb. Thus, in addition to causing direct pathogenicity, inoculation of plants with B. bassiana negatively impacted A. gossypii physiology and reproductive performance and could usefully complement other strategies for managing cotton aphids on greenhouse cucumber.

Effects of nutrient solution irrigation quantity and powdery mildew infection on the growth and physiological parameters of greenhouse cucumbers

For important economic crops such as cucumbers, abiotic and biotic stress conditions have had an adverse effect. This study aimed to observe the effects of water stress and powdery mildew stress on cucumber plants. Biotic stress at two levels, B0 (no powdery mildew stress) and B1 (powdery mildew stress) with three fertigation requirement levels (T1: Full fertigation, T2: Moderate nutrient solution deficit, T3: Severe nutrient solution deficit). Therefore, set up six treatments of B0T1, B1T2, B0T3, B1T1, B1T2, and B1T3. Leaf gas-exchange parameter first decreases and then increases under B1T1, B1T2, and B1T2. The leaf gas exchange parameter was significantly decreased under B0T2 and B0T3. Compared to the control experiment (CK, B0T1: no disease infestation and full irrigation), the plant height of cucumber decreased by 7.55%, 10.62%, 15.28%, 23.27%, and 35.16%, respectively, under B0T2, B0T3, B1T1, B1T2 and B1T3; the stem diameter of cucumber decreased by 9.46%, 15.74%, 5.47%, 13.45%, and 23.72%, respectively, under B0T2, B0T3, B1T1, B1T2, and B1T3; the leaf area of cucumber decreased by 13.76%, 29.96%, 13.43%, 38.21%, and 66.83%, respectively, under B0T2, B0T3, B1T1, B1T2, and B1T3. The root-shoot ratio of cucumber was 3.92%, 3.13%, 3.63%, 3.84%, 4.41%, and 3.82%, respectively, under the B0T1, B0T2, B0T3, B1T1, B1T2, and B1T3. Therefore, this study can provide a basis for the research on greenhouse environmental control and cucumber cultivation management. Keywords: greenhouse, cucumber, powdery mildew, nutrient solution, drought stress, growth traits, physiological traits DOI: 10.25165/j.ijabe.20221502.6838 Citation: Mao H P, Wang Y F, Yang N, Liu Y, Zhang X D. Effects of nutrient solution irrigation quantity and powdery mildew infection on the growth and physiological parameters of greenhouse cucumbers. Int J Agric & Biol Eng, 2022; 15(2): 68–74.

The Effect of Increasing the Dose of Acetamiprid and Dichlorvos Pesticides on the Reproductive Performance of Laboratory Mice.

Pesticides are widely used around the world. However, these chemicals are being used more frequently and at increased doses in underdeveloped and developing countries. Although the hazard of pesticides has been studied in ecological fields, the effect of residual amounts of these compounds on the physiological processes of the body has always been debated. In this experimental study, 45 greenhouse cucumber plants were sprayed with dichlorvos and acetamiprid pesticides in concentrations of twofold (acetamiprid 500 g/1000 L and dichlorvos 4 L/1000 L) and threefold of the recommended dose. After 24 h, the residual amount was obtained. To evaluate the residual effect of the mentioned pesticides, an equivalent of this residue was added to the drinking water of 105 mice. Pesticide residues were obtained for twofold and threefold concentrations of the recommended dose, 1.5 and 2.5 (mg/kg cucumber) for acetamiprid and 0.5 and 1 (mg/kg cucumber) for dichlorvos, respectively. Application of these chemicals at higher doses not only significantly reduced the body weight, food consumption, testosterone production, testicular germ cells and embryo numbers, but also increased the levels of follicle-stimulating hormone and luteinizing hormone in mice. The emergence of biological disorders and reducing reproductive potential in male mice can be attributed to the addition of pesticides to their drinking water. Therefore, to reduce the hazards caused by insecticides, it is recommended to familiarize farmers with the harmful effects of overdose of pesticides and monitoring the residuals in agricultural products.

Simulation of greenhouse cucumber growth, water and nitrogen dynamics in areas with high groundwater (HG) levels using the HG EU-Rotate_N model

The fruit yields of cucumber are always associated with high inputs of nitrogen, which poses a risk of pollution to the environment. The EU-Rotate_{_}N model has been used widely for its good performance in the simulation of vegetable growth, water and nitrogen dynamics. However, whether the underground water level affects the performance of the EU-Rotate_{_}N model is unclearly. In this study, we modified the groundwater level algorithms to the original model and named the modified model “the HG EU-Rotate_N model”. Experiments over two years on greenhouse cucumber with four different nitrogen (N) treatments (N1-N4) were conducted in Jiangsu Province, China, which has a high groundwater level (area_HG). Both original and modified models were used to simulate cucumber growth, water movement and N fate. For the soil water content, the measured values were significantly larger than the simulated values of the original model (value_O) and closer to those of the HG model (value_HG); for the soil available nitrogen concentration (SNC), the measured values were significantly higher and lower than value_O in 0-10 cm and 10-30 cm soil layers, respectively, and were also closer to those of the values_HG. The higher SNC in the 0-10 cm soil layer indicated that a high groundwater level might increase the upwards movement of water and nitrogen in the 0-30 cm soil layer. The root mean square error, Nash Sutcliffe Efficiency and difference values show that the HG model was more applicable for area_HG than the original model. In this study, the nitrogen dosage of the N3 treatment was sufficient to meet the requirements of the cucumber growth, indicating that the fertilization recommendation according to nitrogen nutrient balance was applicable in this area.

Morphology, growth, and physiological traits of greenhouse cucumber seedlings as affected by supplementary white and blue LEDs

Morphology, growth, and physiological traits of greenhouse cucumber seedlings as affected by supplementary white and blue LEDs

Assessment of Non-Conventional Irrigation Water in Greenhouse Cucumber (Cucumis sativus) Production

Climate change, urbanization and subsequent environmental changes are depleting freshwater resources around the globe. The reuse of domestic, industrial and agricultural wastewater is an alternative approach to freshwater that can be used for irrigation purposes. However, these wastewaters may contain hazardous and toxic elements, such as heavy metals that are hazardous for human health and the environment. Therefore, an experiment was conducted to evaluate the concentration of macro, micro and heavy metals in cucumber irrigated with different resources (tap water, greywater, dairy water and wastewater). The results showed that the use of different irrigation resources has increased the level of macro (sodium (Na), potassium (K), calcium (Ca), magnesium (Mg)), microelements (zinc (Zn), iron (Fe), manganese (Mn)), and heavy metals (copper (Cu), barium (Ba), lead (Pb) and cadmium (Cd)) in cucumber leaves and fruits. However, their levels were in the range that is safe for human health and the environment was as recommended by FAO maximum values of trace elements (Zn, 2.0; Fe 1.0; Mn, 0.2; Cu, 0.2; Pb, 5.0, and Cd, 0.01 mgL−1). Based on observations, it was also revealed that among different irrigation resources, the use of dairy water in cucumber improved its agronomic attributes and maximum plant yield (1191.02 g), while the different irrigation resources showed a non-significant impact on fruit diameter. However, total soluble solid contents (TSS) were more significant in cucumber fruits treated with wastewater (2.26 °brix) followed by dairy water (2.06 °brix), while the least TSS contents (1.57 °brix) were observed in cucumber plants treated with tap water. The significance of non-conventional irrigation water use in agriculture, particularly greenhouse cucumber (Cucumis sativus) production, is discussed.

Pesticide residues in green-house cucumber, cantaloupe, and melon samples from Iran: A risk assessment by Monte Carlo Simulation

This research aims to analyze 56 pesticide residues in 100 green-house cucumber and 150 cantaloupe and melon samples collected from markets in Iran by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction method based on analysis with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). In addition, non-carcinogenic and carcinogenic probabilistic health risk assessments were evaluated by Hazard Quotient (HQ), Hazard Index (HI), and Carcinogenic Risk (CR) based on the Monte Carlo Simulation (MCS) method. According to Iranian regulation, 18% of cucumber and 22% of cantaloupe and melon samples were contaminated by at least one pesticide. Arrange pesticides based on HQ ranking was diazinon > thiacloprid > imidacloprid tebuconazole for cucumbers and chlorpyrifos > thiacloprid > imidacloprid > metalaxyl for cantaloupes and melons. In addition, HI for adults was 0.067 in cucumber and 0.24 in cantaloupe and melon; and for children, 0.30 in cucumber and 0.60 in cantaloupe and melon. Arrange pesticides based on CR ranking was thiacloprid > imidacloprid > metalaxyl > chlorpyrifos > tebuconazole > diazinon. However, CR was more than 1.0E-6 value due to thiacloprid, so consumers were at considerable carcinogenic risk in these commodities.

Reducing the environmental risks related to phosphorus surplus resulting from greenhouse cucumber production in China

Excessive phosphorus (P) inputs from manure and synthetic fertilizers leads to high environmental risk in greenhouse vegetable production systems. In the current study, we determined whether a system of P fertilization that attempts to achieve a zero-P surplus balances agronomic, economic, and environmental concerns. A field experiment was conducted to evaluate the potential of integrated inorganic and organic nutrient management to provide both high yield and minimal environmental risk in a typical region of greenhouse vegetable production in China. Three treatments were compared: farmers’ practice (FP), current recommended nutrient management (CRNM), and designed balanced nutrient management (DBNM, with P input optimized based on crop demand). The results indicated that in the greenhouse cucumber production system, the seasonal P surplus of FP was as high as 410 kg P ha−1; this increased the movement of P to the subsoil, causing a high risk of P loss, i.e., a P index >9, and a high eutrophication potential (87.4 kg PO4-eq ha−1). Compared with FP, CRNM (which had a 76% lower P fertilizer input) significantly reduced the P surplus, the risk of P loss, and the eutrophication potential, and increased yield incomes and net ecosystem economic benefits by 18.0% and 31.8%, respectively. Compared with CRNM, DBNM significantly reduced the P surplus by 84.5% and the environmental damage cost by 19.0%, while increased the input cost by 23.0%. Therefore, the DBNM strategy is recommended in greenhouse vegetable production to reduce the P surplus and environmental costs, and to obtain high yield and economic benefits.

African endemic stingless bees as an efficient alternative pollinator to honey bees in greenhouse cucumber (Cucumis sativus L)

The current honey bee decline necessitates the use of alternative native pollinators to ensure global food security. Here, we compared the pollination behaviour and efficiency of the African honey bee (Apis mellifera) and six African endemic Meliponini (Meliponula bocandei, Dactylurina schmidti, Meliponula lendliana, Hypotrigona gribodoi, Meliponula ferruginea and Meliponula togoensis) in a greenhouse with the non-parthenocarpic cucumber variety Super Marketer. Honey bees and D. schmidti started foraging on introduction in the greenhouse, while M. lendliana and M. togoensis showed the longest delay. In most species, foragers collected nectar and pollen, excepting M. bocandei that specialized in nectar collection, and H. gribodoi and M. togoensis, specialized in pollen collection. African honey bees visited flowers the shortest, while H. gribodoi and D. schmidti had a 2-fold probing time, on average. Most stingless bees species had a lower hive activity with fewer foragers encountered per hour than for honey bees, except D. schmidti. M. bocandei, M. ferruginea, A. mellifera scutellata and H. gribodoi, yielded a seed germination percentage of around 90%. M. lendliana, M. togoensis and D. schmidti yielded a much lower seed germination percentage around 30%, which indicates that the quality of pollination was remarkably lower by using these three species. The highest sugar content was recorded in fruits from flowers pollinated by M. bocandei, African honey bees, D. schimdti or M. togoensis with the same solid content as the gold standard method, i.e., hand cross-pollination. We found that M. bocandei was the most efficient cucumber pollinator of all species tested: because pollination by this species yielded the largest and heaviest fruits and the highest seed numbers.

Energy and Water Related Parameters in Tomato and Cucumber Greenhouse Crops in Semiarid Mediterranean Regions. A Review, Part II: Irrigation and Fertigation

Increasing agricultural systems’ resource efficiency is the key action for producing adequate food quantities in semi-arid Mediterranean regions while coping with water scarcity, environmental constraints and economic issues. Optimisation of irrigation and fertigation practices imposes different approaches, considering plant-water-soil relationships based on prevailing greenhouse microclimatic conditions, ensuring optimal production per drop of water and unit of fertiliser. In the content of "precision agricultural farming systems", nutrient uptake modelling, phyto-sensing, smart and sustainable technologies must be applied for monitoring and evaluating water and nutrients crops supply. However, in many cases, the use of irrigation and fertigation recipes given in the literature may not be compatible in the Mediterranean, as they usually originated based on northern European climatic conditions. The objective of this work is an attempt to understand various aspects of irrigation and fertigation management in vegetable fruiting crops such as tomato and cucumber towards nutrients and water resource sustainability in Mediterranean greenhouses.