Investigating chemical and microbial functional indicators of nutrient retention capacity in greenhouse stormwater retention ponds in southwestern Ontario, Canada

The tributaries flowing through Leamington, Ontario are unique in the Canadian Lake Erie watershed due to the broad spatial extent of greenhouse operations, which more than doubled in size and density from 2011 to 2022. These greenhouse operations are considered to be potential nutrient point sources with respect to observed nutrient concentrations in tributaries adjacent to greenhouse stormwater retention ponds (GSWPs). Identifying causal factors of nutrient release, whether this be chemical or biological, within these ponds may be critical for mitigating their impact on the watershed and ultimately the receiving waters of Lake Erie. Specifically, phosphorus and nitrogen accumulation in freshwater ponds can contribute to environmental damage proximal to adjacent streams, serving as a potential catalyst for algal blooms and eutrophication. This study compared correlations between the water column N:P stoichiometry, sediment nutrient retention capacity, and drivers of microbial metabolism within GSWP sediments. Correlations between water column TN:TP ratios and sediment nutrient retention capacity were observed, suggesting an interplay between N and P in terms of nutrient limitation. Further, clear shifts were observed in the bacterial metabolic pathways analyzed through metatranscriptomics. Specifically, genes related to nitrogen fixation, nitrification and denitrification, and other metabolic processes involving sulfur and methane showed differential expression depending on the condition of the respective pond (i.e., naturalized wetland vs. dredged, eutrophic pond). Collectively, this research serves to highlight the interconnected role of chemical-biological processes particularly as they relate to significant ecosystem processes such as nutrient loading and retention dynamics in impaired freshwater systems.

Species identification of introduced veronicellid slugs in Japan

Reliable identification of species is important for protecting native ecosystems against the invasion of non-native species. DNA barcoding using molecular markers, such as the mitochondrial cytochrome oxidase subunit 1 (COI) gene, helps researchers distinguish species. In this study, we focused on introduced veronicellid slugs in the Ryukyu Islands and some greenhouses on mainland Japan. Some veronicellids are medium-to-high risk pest species for humans. Identifying veronicellid species by their external morphology is difficult and unreliable because there is substantial overlap between intraspecific variation and interspecific differentiation. Therefore, internal morphologies such as male genitalia have been the primary traits used to distinguish veronicellids. To identify introduced veronicellid slugs in Japan to the species level, we used morphological assessment of male genitalia and DNA barcoding of the standard COI gene fragment. We also conducted species-delimitation analyses based on the genetic data. The results showed that five evolutionarily significant units, corresponding to four nominal species inhabit the Ryukyu Islands, of which two species were also found in the greenhouses of mainland Japan, including the first record of Sarasinula plebeia in Japan. The presence of non-native slug species could increase the transmission of parasites in Japan.

Environmental fate of dibutylphthalate in agricultural plastics: Photodegradation, migration and ecotoxicological impact on soil

Phthalic acid esters (PAEs) were determined in polyethylene covers used in horticultural production units located at Moreno and La Plata districts (Buenos Aires, Argentina), detecting 0.69-8.75 mg PAEs kg^-1 plastic in greenhouse and tunnel films. The PAEs found were diisobutylphthalate (DIBP), dibutylphthalate (DBP) and diethylhexylphthalate (DEHP). DBP was chosen as a model molecule to carry out the photochemical degradation studies that led to the formation of monobutylphthalate (MBP) and phthalic acid (PA). DBP, MBP and PA migration from plastic covers was studied, finding that while DBP and MBP moved to soil and atmosphere in short times (<48 h), PA remained in the agricultural covers. Further experiments with DBP were made to explore the effect on migration of temperature (20 °C, 50 °C), film thickness (25 μm, 100 μm) and plastic ageing by solarization, observing that temperature increase, film thickness reduction and ageing by solarization favored DBP migration to the environment. DBP and MBP impact on soil were evaluated by avoidance and reproduction tests using Eisenia andrei as bioindicator. Both compounds reduced cocoon viability decreasing the number of juveniles at the lowest concentration assayed (0.1 mg kg^-1 of soil). At higher DBP and MBP concentrations the reproductive parameters (number of total cocoons, hatchability and number of juveniles) also showed alterations compared with the controls. Carboxylesterases (CaE), cholinesterases (ChE) and glutathion-S-transferases (GST) activities were analyzed in E. andrei exposed to DBP; cholinesterases activities were reduced at 1 and 10 mg DBP kg^-1 soil, and glutathione S-transferases activities were increased at 10 mg DBP kg^-1 soil while no effect was observed on carboxylesterases activities. These results emphasize the need to continue studying the impact of PAEs and their photodegradation products on the environment.

Identification problems of travelling snail species-new exotic introductions to tropical greenhouses in Gothenburg, Sweden (Gastropoda: Achatinellidae, Strobilopsidae, Helicarionidae)

Three previously unreported species of tropical land snails were found in the greenhouses of the Gothenburg (Göteborg) Botanical Garden and the Public Science Center Universeum in Gothenburg. For Tornatellides cf. boeningi (Schmacker & Boettger, 1891) and Ovachlamys fulgens (Gude, 1900) this is the first observed occurrence in a European greenhouse, while Discostrobilops hubbardi (Brown, 1861) was first reported very recently in the Vienna Botanical garden. Tornatellides and Discostrobilops seem to be spread with orchid culture and trade. Identification of the Tornatellides species proved extremely difficult and a genetic sequence-based approach completely failed due to the unavailability of reference data. This was unexpected considering the importance of these introduced species in horticultural trade. A broader assessment of available sequence data for genetic identification based on COI or 16S for other snail species reported from horticultural facilities showed that such reference data in GenBank are still scarce and only for a limited number of species this approach would support identification.

Greenhouse agricultural plastic waste mapping database

Agricultural waste mapping is an indispensable tool for the development and adoption of sustainable waste management practises in the agricultural sector. Current practices of agricultural plastic waste (APW) management in countries with large agricultural areas and thus high generation volumes of APW include uncontrollable disposal in fields or near water sources, or uncontrolled burning of the waste. These practices lead to irreversible deterioration of the natural environment through land and soil contamination, contamination of freshwater resources, air pollution and also pose public health issues. Given these negative effects on the environment, spatial prediction of APW generation becomes significant in sustainable agriculture. This dataset consists of the coordinates of the agricultural plots identified in the Republic of Cyprus and the area in square meters covered by agricultural greenhouses. The dataset has been used to perform APW generation mapping and predict the national generation quantities of waste low- density polyethylene (LDPE). The collection of the data is included in sixteen tables separated per geographical area-cluster. The agricultural plastic waste (APW) generation mapping was conducted with the use of up-to-date statistics from Cyprus Agricultural Payments Organization (CAPO), geographic information system (GIS) and satellite imagery.

Development and application of photoconversion fluoropolymer films for greenhouses located at high or polar latitudes

To convert and store energy in the process of photosynthesis, plants primarily use quanta of the red and blue parts of the spectrum. At high latitudes, the average daily intensity of red and blue parts of the spectrum is not very high; for many crops cultivated under greenhouse conditions, it reaches the sufficient level only on clear summer days. The problem of insufficient illumination in greenhouses is usually solved with artificial light sources. This article describes a technology for the manufacture of photoconversion fluoropolymer films for greenhouses. The fluoropolymer films described in the paper make use of original gold nanoparticles and nanoparticles with fluorescence in the blue or red region of the spectrum. In the polymer film, nanoparticles aggregate in the form of "beads", which enhances the field of the optical wave. The film photoconverts UV and violet light into blue and red light. Gold nanoparticles also partially convert energy in the green region of the spectrum (not used by plants) into heat, which is also important for agriculture at high latitudes. In addition, impregnation of gold nanoparticles into fluoropolymer significantly increases the lifetime of the film. The films described in the paper can significantly increase the productivity of greenhouses located at high latitudes. Plants cultivated under the films have more chlorophyll and a higher intensity of photosynthesis - although their system of distance stress signals is, to a certain degree, suppressed.

Presence, distribution and risk assessment of phthalic acid esters (PAEs) in suburban plastic film pepper-growing greenhouses with different service life

The widespread usage of plastic film increased the content of phthalic acid esters (PAEs) in the environment, causing PAE residue in vegetables and subsequently increasing health risks to humans when consuming them. In this work, the presence, distribution and risk assessment of 15 PAEs in soils and peppers from suburban plastic film pepper-growing greenhouses were investigated. The total PAE contents in soil and pepper samples ranged from 320.1 to 971.2 μg/kg (586.3 μg/kg on average) and from 196.6 to 304.2 μg/kg (245.4 μg/kg on average), respectively. Di (2-ethyl)hexyl, dibutyl and diisobutyl phthalates (DEHP, DnBP and DiBP, respectively) were the most abundant in both soil and pepper samples. Specifically, DEHP showed the highest content in soils, while the DnBP content was the highest in peppers. The total PAE content in soils from pepper-greenhouses was much lower than in the agricultural soils mulched with plastic films, but significantly higher than in the agricultural soils from open uncovered fields. The total PAE content in peppers decreased as the service life of plastic film greenhouses increased. Correlation analysis suggested that the difference in distribution and accumulation behaviors of individual PAEs in greenhouse systems was correlated with their physicochemical properties. The non-cancer and carcinogenic risks of priority PAEs show low risks of PAEs detected in pepper and soil samples from the suburban plastic film greenhouses to human health.

Scaling of greenhouse crop production in low sunlight scenarios

PURPOSE

During a global catastrophe such as a nuclear winter, in which sunlight and temperatures are reduced across every latitude, to maintain global agricultural output it is necessary to grow some crops under structures. This study designs a method for scaling up crop production in low-tech greenhouses to contribute to global food sustainability during global catastrophic conditions. Constructing low-tech greenhouses would obviate growing crops using more expensive and energy intensive artificial light.

METHODS

A nuclear winter climate model is used to determine conditions for which greenhouses would need to compensate. The greenhouse structures are designed to utilize global markets of timber, polymer film, construction aggregates, and steel nails.

RESULTS

The limiting market that determines the growth rate of the greenhouses is the rate at which polymer film and sheet are currently extruded. Conditions under low-tech greenhouses in the tropics would feasibly accommodate the production of nearly all crops. Some supplemental lighting would be required for long day crops.

CONCLUSIONS

The analysis shows that the added cost of low-tech greenhouses is about two orders of magnitude lower than the added cost of artificial light growth. The retail cost of food from these low-tech greenhouses will be ~2.30 USD/kg dry food higher than current costs; for instance, a 160% retail cost increase for rice. According to the proposed scaling method, the greenhouses will provide 36% of food requirements for everyone by the end of the first year, and feed everyone after 30 months.

Preliminary study on the variation of radon-222 inside greenhouse of Shouguang county, China

Studies on radon have become the focus of indoor radiation. In this study, we chose greenhouse to be the study field, the research aims to: (1) explore the diurnal variation of radon concentration inside greenhouse in Shouguang county, China; (2) pre-analyze the relationship between radon concentration, temperature and relative humidity, and shed light on the radon behavior characteristic inside greenhouse; (3) verify the feasibility of calculating radon radiation dose by using short-period detected radon concentrations in typical months in Shouguang county. The following conclusions were drawn. Firstly, the average radon levels in typical months in Shouguang county are all much higher than that in ordinary dwellings in China, diurnal and seasonal variations in radon levels are observed inside greenhouse. Secondly, temperature and relative humidity may play a role indirectly through affecting soil moisture and other factors. The mechanism need to be further studied. Thirdly, radon concentrations detected in typical months are still useful in preliminary estimation of radon radiation dose for vegetable-plant farmers in Shouguang county.

Polyethylene film incorporation into the horticultural soil of small periurban production units in Argentina

Horticulture makes intensive use of soil and extensive use of polyethylene (PE) sheeting and pesticides, producing an environment where the dynamics between soil and plastics can affect pesticide fate. We have determined that the presence of plastic residues in the horticultural soil of small production units equals 10% of the soil area, being meso and macro-sections the predominant fragment sizes. All soil samples were taken from different plots located in Cuartel V, Moreno district, in the suburbs of Buenos Aires city, Argentina. Laboratory experiments were conducted to see the relations among pesticide, soil and PE film. Endosulfan recovery from LDPE films (25μm and 100μm) was studied, observing evidence that indicated migration to the inside of the plastic matrix. To further analyze the dynamics of pesticide migration to soil and atmosphere, experiments using chlorpyrifos, procymidone and trifluralin were performed in soil-plastic-atmosphere microenvironments, showing that up to 24h significant amounts of pesticides moved away from the PE film. To determine whether PE residues could act as potential pesticide collector in soil, column elution experiments were done using chlorpyrifos, procymidone and trifluralin. Results showed an important pesticide accumulation in the mulch film (584μg-2284μg pesticide/g plastic) compared to soil (13μg-32μg pesticide/g soil). Finally, chemical and photochemical degradation of deltamethrin adsorbed in PE film was studied, finding a protective effect on hydrolysis but no protective effect on photodegradation. We believe that a deeper understanding of the dynamics among soil, plastic and pesticides in horticultural productive systems may contribute to alert for the implications of PE use for plastic sheeting.

Volatilisation of pesticides after application in vegetable greenhouses

BACKGROUND

Volatilisation of pesticides after application to the soil or the crop is an important source of emission into the atmosphere. As a result, workers, residents and bystanders are potentially at risk when exposed to these volatilised substances. Nonetheless, data on measured concentrations are quite scarce, especially in greenhouses. The objective of this work is to present the results of volatilisation experiments performed in greenhouses.

RESULTS

The results indicate that the concentrations are highest in the hours after application and rapidly decline during the days following application.

CONCLUSION

Greenhouse temperature, ventilation rate, the substance vapour pressure and the rate of competing processes were identified as important factors influencing volatilisation in greenhouses. The results from this study contribute to a better understanding of volatilisation in greenhouses and may help to improve the recent PEARL model for volatilisation in greenhouses.