Tomato Production Research Articles

Progressing environmental sustainability in hydroponic greenhouse systems: Embracing circular bioeconomy through compost and biochar pathways

The global population growth and awareness about the important role of vitamins in human health drive demand for fresh fruits and vegetables. In line with this need, greenhouse cultivation addresses year-round availability, but chemicals pose challenges. Hydroponic systems control pests, boost yields, and decrease chemicals while faced with significant waste generation. Waste generated by hydroponic systems holds potential for repurposing into value-added products, which aligns with the principles of the circular bioeconomy. However, before embracing widespread adoption, it is crucial to assess its environmental compatibility. This study employs a life cycle assessment approach to compare hydroponic tomato production in greenhouses under conventional and circular bioeconomy systems. The first scenario (Sc-1) encompasses hydroponic tomato production in a greenhouse system under a conventional system. The second scenario (Sc-2) involves the production of tomatoes, along with the conversion of residue of tomato production into compost. The third scenario (Sc-3) closely resembled Sc-2, while valorizing residue of tomato production into biochar. The outcomes indicate that per kg of tomato production under Sc-1 leads to a damage of 4.32 × 10−6 DALY to human health, 4.33E−06 species.yr to ecosystems, and 1.82 × 10−1 USD2013 to resources. The results of weighting of environmental damages also shows a total environmental damage of 75.36 mPt per kg of tomato production under Sc-1 which is mainly based on the production and consumption of natural gas. The findings demonstrate that Sc-2 and Sc-3 exhibit a diminished potential on damage to human health, ecosystems, and resource compared to Sc-1, respectively. Accordingly, in comparison to Sc-1, Sc-2 leads to an approximately 11% reduction in total weighted environmental impacts, while Sc-3 results in an approximately 4% reduction in total weighted environmental impacts. Based on these outcomes, integrating compost and biochar production into hydroponic tomato systems holds significant potential for environmental benefits. Accordingly, further research and development efforts should focus on optimizing the efficiency and scalability of composting and biochar production technologies to maximize their impact on sustainability in hydroponic tomato production.

Pests, Diseases, Growth and Yield of Tomato as Influenced by Variety and Cultivation Technology

Tomato (<i>Solanum lycopersicum</i> L.) is one of the most important vegetables in the world. However, dearth of knowledge exists on cultivation technology that contributes to increased production of the crop. Meanwhile, low yielding varieties, high pests and diseases attacks, climate variability and poor soil fertility are among key production constraints that limit the increased production and productivity of tomato in Sierra Leone. A two-year field experiment was conducted at the School of Agriculture and Food Sciences experimental site during 2022 and 2023 to evaluate the effects of variety and cultivation technology (CT) on pests, diseases, growth, yield and productivity of tomato. The experiment was laid in a 2 × 4 factorial (i.e. two varieties of tomato, and four treatments: CT 1, CT 2, CT 3 and CT 4 known as control) arranged in a randomized complete block design (RCBD) with three replications. Results showed that organic (CT 1 and CT 2) and inorganic (CT 3) treatments had a positive impact on growth parameters of tomato. The CT 1 (chicken dung, mulching, and neem extract biopesticide) was most effective in promoting vegetative growth and higher fruit yield, while CT 2 (NPK 15:15:15, urea, promethrin herbicide, and chlorpyrifos pesticide) exhibited highest potency in reducing population and damage caused by diseases and pests. Findings demonstrate that improved variety and cultivation technology boost tomato tolerance to pests and diseases, as well as its growth and yield performances that could be exploited for increased production and fruit quality of the crop. The CT1 was the most effective, followed by CT 2, while CT 4 or control plots had the lowest performance. The outperformance of the organic treatments relative to the inorganic and control is suggested to be attributable to its nitrogen-rich components. Weed control was also established to be effective in both inorganic and CT 2 treatments. The findings suggest that the CT 1 should be promoted for sustainable tomato cultivation, prioritizing environmentally friendly methods for long-term success.

Ecofriendly Management of Two Spotted Spider Mites on Tomato (Solanum lycopersicum) (Mill) in Eastern Ethiopia

This study was initiated with the objective to evaluate the efficacy of tobacco leaf extract and potentiality of intercropping on TSSM in Eastern Ethiopia. The tomato, tomato + cabbage, tomato + common bean, tomato + onion, tomato + tobacco leaf extract and tomato + karate 5% EC were the treatments used for the trial. The overall result indicated that intercropping and tobacco leaf extract significantly reduced the population of these mite pests compared to sole tomato. The minimum population with infestation was recorded on karate (14.65, 0.79) followed by tomato – tobacco leaf extract (16.50, 0.92) and tomato onion (36.53, 1.74) from intercropping while control was the most in recording maximum population with maximum infestation (94.10, 2.88 respectively). The most population reduction with infestation was observed on tobacco leaf extract compared to untreated plot followed by tomato-onion intercropping. The highest yield (50.73tha-1) was recorded on the tomato-onion intercrops followed by karate 5%EC (43.96tha-1) and tobacco extract (43.65tha-1) while the lowest yield was recorded on head cabbage intercrops (30.10tha-1). The maximum net benefit was obtained from tomato-onion intercrops (688653.45 ETB) whereas the lowest net benefit was recorded on common bean (354176.60 ETB) intercrops. Therefore, tomato onion intercrops and tobacco leaf extract could be considered as the first options in boosting tomato production as an alternative to karate 5%EC and expected as common integrated management of TSSM on tomato.

Prediction of Total Soluble Solids Content Using Tomato Characteristics: Comparison Artificial Neural Network vs. Multiple Linear Regression

Tomatoes are among the world’s most significant vegetables, both in terms of production and consumption. Harvesting takes place in tomato production when the important quality attribute of total soluble solids content reaches its maximum possible level. Tomato total soluble solids content (TSS) is among the most crucial attribute parameters for assessing tomato quality and for tomato commercialization. Determination of total soluble solids content by conventional measurement methods is both destructive and time-consuming. Therefore, the tomato processing industry needs a rapid identification method to measure total soluble solids content (TSS). In this study, we aimed to estimate how much soluble solids there are in beef tomato fruit by Artificial Neural Networks (ANN) and Multiple Linear Regression (MLR) methods. The models were assessed using the Coefficient of Determination (R2), Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE) metrics. The training data set results of the MLR model established to estimate the amount of brix in tomato fruit, calculated as MAE: 0.2349, RMSE: 0.3048, R2: 0.8441, and MAPE: 5.5368, while, according to the ANN model, MAE: 0.0250, RMSE: 0.031, R2: 0.9982 and MAPE: 0.5814. According to the metric outcomes, the ANN-based model performed better in both the training and testing parts.

Towards a modelling, optimization and predictive control framework for smart irrigation

Smart irrigation scheduling is a promising approach for improving the efficiency and sustainability of agricultural water use, especially in arid and semi-arid lands. In this paper, we present a design and simulation of a model predictive controller for smart irrigation scheduling. The proposed controller is based on a mathematical model of the irrigation system, which is used to predict the future states of the system and determine the optimal irrigation schedule for a given crop and field. This study further evaluates the impact of the predictive control framework on crop yield, water use efficiency (WUE), and water savings in tomato production. Three control strategies, including manual control, open-loop control, and model predictive control (MPC), were compared using a Completely Randomized Design (CRD) methodology. Results indicate that MPC outperforms the other strategies, yielding the highest average crop yield of 20 t/ha and demonstrating superior WUE at 10.4 kg/m3. Additionally, MPC significantly reduces water consumption, achieving a 29 % and 8 % savings compared to manual and open-loop control, respectively. These findings underscore the efficacy of MPC in optimizing crop yield, conserving water resources, and promoting sustainable agriculture practices. The proposed controller has the potential to address the global water scarcity challenge and contribute to the sustainability of agriculture in arid and semi-arid lands.

Field assessment of Lake Erie dredged sediment for specialty crops cultivation

AbstractAnnually, approximately 1.5 million tonnes of sediment are dredged from federal navigational channels in Lake Erie. Recognizing the potential influence of Lake sediments on soil compaction, structure, water retention capacity, and aeration, this research assessed the agronomic performance of selected specialty crops under varying sediment ratios in an open‐field production system. The experimental design involved three sediment application rates: 0 tonne (100% farm soil), 0.7 tonne (90% farm soil and 10% sediment), and 7 tonnes per bed (100% sediment). Lettuces (Lactuca sativa L.) were harvested 35 days after planting, with assessments including fresh and dry weights of leaves root biomass and root length measurements. Radishes (Raphanus sativus L.) were evaluated for root length, leaf fresh weight, root fresh weight, and diameter. Tomatoes (Solanum lycopersicum L.) plants were monitored for plant height and stem diameter. Fruit harvest occurred at days 70 and 75 post‐transplant. Metrics such as total number of marketable fruits, total fruit weight, number of US grade‐1 fruits, and polar and equatorial diameters were recorded. The results revealed significant positive effects of the 7‐tonne sediment treatment on lettuce, including increased dry leaf and root biomass, root lengths, and fresh weight. Similarly, radishes exhibited enhanced weight and length when grown in beds with 7 tonnes of sediment. Tomatoes from the 7‐tonne sediment treatment displayed higher values in plant measurements and harvested fruits. Overall, the findings indicate that soils treated with Lake Erie sediment positively influence the development and production of lettuce, radishes, and tomatoes compared to untreated soils.

Prediction of yield based on fruit set and dry matter production in greenhouse tomato

Prediction of yield based on fruit set and dry matter production in greenhouse tomato

Compost tea from oil palm empty fruit bunch (EFB) enriched with chicken manure as a fertiliser source in organic production of tomato (Solanum lycopersicum)

Compost tea from oil palm empty fruit bunch (EFB) enriched with chicken manure as a fertiliser source in organic production of tomato (Solanum lycopersicum)

EFFET COMPARE DES FERTILISATIONS ORGANIQUES ET MINERALES SUR LA PRODUCTION ET LA CONSERVATION DE LA TOMATE FRAICHE (Solanum lycopersicumL.) DANS LA PREFECTURE DE LA KOZAH AU TOGO

The tomato (Solanum lycopersicum) is a crucial vegetable for human nutrition and an important source of income for farmers. In response to increasing demand, producers increasingly use chemical inputs, raising serious health and environmental concerns. As a perishable fruit, the tomato rapidly deteriorates after ripening, making preservation a major challenge. To promote sustainable production and conservation, a study was conducted at the agriculturalexperimental station of the University of Lome, located atTchitchao, in the Kara region of Togo. The study assessed the effects of four types of fertilizers on agronomic parameters and the shelf life of two tomato varieties - ANAYAand MONA. A randomized block design was employed, with five treatments: SR1 GOLD, poultry manure, compost, NPK, and a control. The results indicate that poultry manure significantly enhances the growth, yield, and conservation of tomatoes compared to the other treatments. The application of 20 t/ha of poultry manure increased production by 86.67% for the MONAvariety and 65.11% for the ANAYAvariety compared to the control. Additionally, the manure extended the shelf life by two weeks for MONA and one week for ANAYA, compared to the NPK treatment, under ambient conditions. Under refrigerated storage, tomatoes treated with poultry manure exhibited the lowest rate of spoilage up to the tenth week, suggesting that poultry manure is a viable alternative for improving both the production and preservation of tomatoes.

Effect of Organic Granules on the Productivity, Quality, and Nutrient Uptake Level of Tomato and the Fertility and Microbial Population of the Soil

Organic vegetable production is needed worldwide to minimize the use of inorganic fertilizers, protect the environment, and produce healthy food. Accordingly, in the present study, the effects of organic granules on the productivity, quality, and nutrient uptake level of tomatoes and the fertility and microbial population of the soil were determined. Briefly, organic NPK granules and organic N, P and K-rich sources were compared with synthetic NPK granules and synthetic fertilizers administered at 100 and 75% of the recommended fertilizer levels. Among the various treatments applied, treatment with 100% of the recommended NPK using the synthetic NPK granules (Urea, DAP and MOP) led to higher growth, yield attributes, and yield (fruit yield, – 24.21 t/ha and stover yield, -15.01 t/ha) of tomato. This treatment also enhanced the nutrient uptake by tomato. However, quality parameters, such as total soluble solids (6.64% ), titrable acidity (0.62% ), ascorbic acid content (14.31 mg/100 g), lycopene content (3.54 mg/100 g), reducing sugars (3.11%), non-reducing sugars (1.02%), total sugar (4.13% ), and shelf life (15.76 days ) of tomato were higher with 100% of the recommended NPK from organic NPK granules than from synthetic granules. This treatment also enhanced the available nutrients and microbial population in the soil. Notably, the same trend was observed for tomatoes fertilized with 75 % of the recommended NPK. The lowest values were obtained with the absolute control. Based on the results of this experiment, the application of 100% of the recommended NPK using organic NPK granules is the best approach to improve the quality of tomato fruits and to enhance the soil fertility.

Potentially toxic metals in Northeast Ethiopian agricultural soils: implications for Solanum lycopersicum (Tomato) production and human health.

Exposure to heavy metal-contaminated vegetables, irrigation water and agricultural soil is one of the most challenging environmental issues worldwide. This study aimed to evaluate the health effects of potentially toxic metals (PTMs) including Cr, Cd, Fe, Pb, Cu, Zn, and Co from agricultural soil, irrigation water, and tomato plants collected from the Abuarie irrigation site, Northeast Ethiopia. The samples were digested using acid digestion method, and its concentration was quantified using Inductively Coupled Plasma-Optical Emission Spectroscopy. The concentrations of PTMs in the soil, tomato, and irrigation water samples ranged from 49,020 ± 275 (Fe) to 11.85 ± 0.44 (Cd), 170 ± 1.98 (Fe) to 0.29 ± 0.006 (Cd) mgkg-1, and 0.24 ± 0.003 (Fe) to 0.025 ± 0.005(Ni)mgL-1 , respectively. The results revealed Zn, Ni, Cd and Cr in soil, all metals in tomato, and Cu, Ni, Cd and Pb in irrigation water sample were above the World Health Organization threshold values. Moreover, the separate and cumulative exposure to farm soil, irrigation water, and consumption of tomato were investigated using the hazard quotient (HQ) and hazard index (HI) values, respectively. The results revealed that individual exposure to each sample type did not have a significant impact on health (HQ < 1). However, simultaneous exposure to all of the sample types (soil, tomato and irrigation water) at the same time had a high likelihood of affecting health (HI > 1). The total carcinogenic concentrations of Cr, Cd, Ni, and Pb were greater than 1 × 10-4, revealing that farmers have a high probability of developing cancer during their lifetime. Minimizing simultaneous exposure to soil, tomato, and irrigated water for local people is highly recommended to prevent the risk of PTMs.

An analytical study on value chain finance to tomato and mango as a component of high value agriculture in the Eastern Uttar Pradesh of India

The study conducted an extensive field survey utilizing pre-tested interview schedules with tomato and mango growers and chain actors. A multi-stage purposive-cum-stratified random sampling method was employed to select sample units. The findings of this study highlight the cost orientation of tomato and mango production, indicating a greater need for consequential credit. The research revealed that growers of both commodities within fragmented value chains had a higher proportionate share in the value addition (price) than growers in integrated chains, primarily due to direct sales of produce to consumers. Additionally, downstream actors such as commission agents, wholesalers, and retailers received a comparatively higher proportionate share in the value additions (price) compared to upward actors, indicating that producers could not effectively compete with increased demand in the marketplace. Observations within the chain indicated that finance for tomato and mango production circulated through a product commitment relationship established between chain participants. Downstream actors provided financing to upstream actors from either their surplus funds or external finance received from financial institutions. The study suggests developing a producer-driven chain financing model as an alternative to the buyer-driven financing model for tomato and mango production. This could be achieved by promoting farmers' organizations as long-term financing strategies for financing institutions.

Analysis of mitochondrial DNA to estimate the population genetic structure of Tuta absoluta (Meyrick, 1917)

Tuta absoluta (Meyrick) has become a serious menace to the sustainable production of tomatoes in Kenya. Investigating the genetic diversity, geographical distribution, and community structure of T. absoluta from various locations utilizing the Cytochrome c oxidase I (COI) of the mtDNA gene information available on NCBI databases. Based on the COI of mtDNA, the haplotype analysis revealed six haplotypes, which displayed low nucleotide (π = 0.00021) diversity. In contrast, haplotype diversity (Hd) was 0.05, and the number of segregating sites (S) was 13. The result showed that the tomato leaf miner population from Central Kenya had high variability in haplotype supported by the haplotype network. Tajima (D) and Fu's Fs were found to be negative (P greater than 0.05), whereas the overall FST value was 0.00077 (P greater than 0.001). In conclusion, genetic analysis showed there was no high variation amongst population from different locations.

Advances in understanding plant-pathogen interactions: insights from tomato as a model system.

The impact of plant diseases coupled with climate change on agriculture worldwide cannot be overemphasized from negative effects on crop yield as well as economy to food insecurity. The model plants are essential for understanding the intricacies of plant-pathogen interactions. One of such plants is the tomato (Solanum lycopersicum L.). Researchers hope to increase tomato productivity and boost its resilience to pathogen attacks by utilizing OMICS and biotechnological methods. With an emphasis on tomato viral infections, this review summarizes significant discoveries and developments from earlier research. The analysis elucidates ongoing efforts to advance plant pathology by exploring the implications for sustainability and tomato production.

Sweet Immunity in Action: Unlocking Stem Reserves to Improve Yield and Quality. A Potential Key Role for Jasmonic Acid.

Common agronomic practices such as stem topping, side branch removal, and girdling can induce wound priming, mediated by jasmonic acid (JA). Low light conditions during greenhouse tomato production make the leaves more sensitive to the application of exogenous sugar, which is perceived as a "danger" in accordance with the concept of "Sweet Immunity". Consequently, source-sink balances are altered, leading to the remobilization of stem starch reserves and enabling the redirection of more carbon toward developing fruits, thereby increasing tomato yield and fruit quality. Similarities are drawn with the mobilization of fructans following defoliation of fodder grasses (wounding) and the remobilization of fructan and starch reserves under terminal drought and heat stress in wheat and rice (microwounding, cellular leakage). A central role for JA signaling is evident in all of these processes, closely intertwining with sugar signaling pathways. Therefore, JA signaling, associated with wounding and sugar priming events, offers numerous opportunities to alter source-sink balances across a broader spectrum of agricultural and horticultural crops, for instance, through the exogenous application of JA and fructans or a combination. This may entail reconfiguring and reversing phloem connections, potentially leading to an enhanced yield and product quality. Such processes may also disengage the growth-defense trade-off in plants.

RNAi targeting Nav and CPR via leaf delivery reduces adult emergence and increases the susceptibility to λ-cyholthin in Tuta absoluta (Meyrick)

The tomato leafminer, Tuta absoluta (Meyrick), one of the most economically destructive pests of tomato, causes severe yields losses of tomato production globally. Rapid evolution of insecticide resistance requires the development of alternative control strategy for this pest. RNA interference (RNAi) represents a promising, innovative control strategy against key agricultural insect pests, which has recently been licensed for Colorado Potato Beetle control. Here two essential genes, voltage-gated sodium channel (Nav) and NADPH-cytochrome P450 reductase (CPR) were evaluated as targets for RNAi using an ex vivo tomato leaf delivery system. Developmental stage-dependent expression profiles showed TaNav was most abundant in adult stages, whereas TaCPR was highly expressed in larval and adult stages. T. absoluta larvae feeding on tomato leaflets treated with dsRNA targeting TaNav and TaCPR showed significant knockdown of gene expression, leading to reduction in adult emergence. Additionally, tomato leaves treated with dsRNA targeting these two genes were significantly less damaged by larval feeding and mining. Furthermore, bioassay with LC30 doses of λ-cyholthin showed that silencing TaNav and TaCPR increased T. absoluta mortality about 32.2 and 17.4%, respectively, thus indicating that RNAi targeting TaNav and TaCPR could increase the susceptibility to λ-cyholthin in T. absoluta. This study demonstrates the potential of using RNAi targeting key genes, like TaNav and TaCPR, as an alternative technology for the control of this most destructive tomato pests in the future.

Antifungal Activity of Erigeron floribundus (Asteraceae) and Ripe Banana Peel-NaHCO3 Extracts on Tomato in South-Kivu/DRC-Albertan Rift in the Great Lakes Region, Central-Africa

Tomato production faces significant challenges from fungal and bacterial diseases, often requiring chemical treatments. This study explores the potential of biopesticides derived from Erigeron floribundus and ripe banana peel-NaHCO3 as sustainable alternatives to conventional fungicides. A completely randomized design was employed to test the efficacy of the biopesticides. Local methods were used to prepare the extracts. Tomato plants were treated with ripe banana peel-NaHCO3, Erigeron floribundus, and a control (Dithane M45). Plant vigor, branch number, and disease incidence were monitored and recorded. Tomato plants treated with ripe banana peel-NaHCO3 showed increased vigor and similar branch numbers compared to those treated with Erigeron floribundus and the control. There was no significant difference in disease incidence between the biopesticides and Dithane M45. Both biopesticides were effective in disease protection and promoting yield, demonstrating their potential as sustainable alternatives to chemical treatments. The study concludes that ripe banana peel-NaHCO3 and Erigeron floribundus extracts are effective in protecting tomato plants from fungal and bacterial diseases while promoting growth and yield. Their non-toxic and environmentally friendly nature makes them suitable for sustainable tomato production.

Harnessing plant-mediated RNAi for effective management of Phthorimaea absoluta by targeting AChE1 and SEC23 genes

Tomato production on a global scale is under persistent pressure due to the devastating impact of Phthorimaea absoluta Meyrick (Lepidoptera: Gelechiidae), the South American tomato leaf miner. To combat this devastating pest, we explored the potential of plant-mediated RNA interference (RNAi) as a novel strategy for its management. Using transgenic techniques, we developed RNAi constructs (p35S::dsAChE1, p35S::dsSEC23) targeting crucial genes, AChE1 and SEC23, in P. absoluta. These genes play pivotal roles in insect physiology and development. The transformation of tomato cultivar Rio Grande was carried out with these RNAi constructs using Agrobacterium tumefaciens. The results demonstrated a significant reduction in transcript levels of both AChE1 and SEC23 in P. absoluta. Silencing AChE1 resulted in substantial mortality rates, reduced larval weight gain, and deformities, highlighting its pivotal role in insect survival. SEC23 gene silencing also induced mortality and influenced insect physiology. Furthermore, we explored the susceptibility of AChE1 to organophosphate insecticides, revealing its relevance in insecticide susceptibility. These findings support the potential of AChE1 and SEC23 as valuable targets for RNAi-based control of P. absoluta for the first time, providing multifaceted insights into insect physiology and insecticide susceptibility, thereby offering valuable insights for the development of effective strategies to mitigate the impact of this destructive pest.

Genotypic Selection Using Quantitative Trait Loci for Better Productivity under High Temperature Stress in Tomato (Solanum lycopersicum L.)

High temperature stress affects tomato production both in tropical and sub-tropical environments worldwide. To explore genetic variation for heat tolerance in tomato, 329 transcontinental tomato genotypes were evaluated at the Ministry of Municipality and Environment (MME) greenhouses near Doha, Qatar, where the average daytime temperature was 38 °C with a big fluctuation during the tomato growth season. A preliminary phenotypic analysis identified a panel of 71 hybrid and pure-line tomato genotypes for more detailed studies. The selected subset was examined in the greenhouse using a randomized complete block design under heat stress. The materials were phenotyped for fruit size, fruit weight, fruit hardness, fruit locules, fruit set, total soluble solids (TSS), and fruit yield. Significant phenotypic differences among genotypes were observed for all the traits assessed. To explore the genetic basis of the variation among the examined genotypes, the subset was genotyped using 104 SNP markers identified in previous heat-tolerance genome-wide association studies (GWAS). Nineteen QTL-associated SNP markers could reliably select heat-tolerant genotypes in terms of better fruit yield, fruit set, and TSS. These markers are located on chromosome 1, 5, 6, 8, 9, and 12. Interestingly, two clusters of markers on chromosome 6 were linked to significant effects on yield, fruit set, and TSS under high temperature. Eighteen out of nineteen SNP markers were mapped within a gene body. Based on the phenotypic and the genotypic analysis, an elite set of five genotypes was selected for approval for heat stress environments in Qatar. The aim of the present work is to provide significant results that are exploitable not only in the Qatar region but also worldwide. Specifically, the 19 molecular markers identified in this study can serve as useful tools for breeders in selecting heat-tolerant material.

Greenhouse study and interviews indicate glyphosate residue via feed-feces-fertilizer route is a risk for horticultural producers using manure-based fertilizer

BackgroundThe herbicide glyphosate is the most widely used active ingredient in pesticides globally. Residues have been found in people, livestock, food and animal feed, and in the environment, but little is known about glyphosate residue in manure-based fertilizer. We describe a feed-feces-fertilizer route of glyphosate contamination with negative impacts for horticultural production. This exposure can harm sensitive plants, such as tomato, and pose a risk to effective waste disposal and nutrient cycling along principles of the circular economy.We review the use and history of glyphosate and present a mixed methods research based on a real-world case from Finland where glyphosate residue in poultry manure fertilizer was suspected of inhibiting commercial organic tomato production. To test the fertilizer, we grew 72 ‘Encore’ variety tomato plants for 14 weeks in a climate-controlled greenhouse according to the practices of the commercial grower. To ascertain awareness and potential contamination mitigation measures, we contacted five fertilizer companies with sales of biogenic fertilizer in Finland, two farming organizations, a feed company, and two government organizations working on nutrient cycling and agricultural circular economy.ResultsThe total harvest of tomatoes grown with fertilizer with the higher content of glyphosate residue was 35% smaller and the yield of first-class tomatoes 37% lower than that of the control, with lower glyphosate concentration. Two of the five fertilizer companies identified poultry manure as a source of glyphosate contamination. Companies with awareness of pesticide residues reported interest in establishing parameters for pesticide residues.ConclusionsThe extent of glyphosate contamination of recycled fertilizers is unknown, but this study shows that such contamination occurs with negative impacts on crop production. Lack of testing and regulation to ensure that recycled fertilizers are free from harmful levels of glyphosate or other pesticides creates risks for agricultural producers. The issue is particularly acute for certified organic producers dependent on these products, but also for sustainable transitions away from mineral fertilizers in conventional farming. The example from Finland shows that a model of co-production between fertilizer producers and state regulatory agencies to establish safe limits can benefit both fertilizer producers and their customers.