{"title":"Bioremediation of environmental wastes: the role of microorganisms","authors":"M. Ayilara, O. O. Babalola","doi":"10.3389/fagro.2023.1183691","DOIUrl":"https://doi.org/10.3389/fagro.2023.1183691","url":null,"abstract":"The growing rate of urbanization and industrialization has led to an increase in several types of pollution caused by the release of toxic chemicals to the environment. This is usually perpetuated by the manufacturing industry (e.g. detergent and dye), agricultural sectors (e.g. fertilizers and pesticides), mining industry (e.g. cyanide and sulphuric acid) and construction companies (e.g. cement and metals). These pollutants have adverse effects on the health of plants, animals, and humans. They also lead to the destruction of the microbial population in both aquatic and the terrestrial regions, and hence, have necessitated the need for remediation. Although different remediation methods, such as the physical and chemical methods, have been adopted for years, however, the drawbacks and challenges associated with them have promoted the use of an alternative which is bioremediation. Bioremediation involves using biological agents such as plants and microbes to remove or lessen the effects of environmental pollutants. Of the two, microbes are more utilized primarily because of their rapid growth and ability to be easily manipulated, thus enhancing their function as agents of bioremediation. Different groups of bacteria, fungi and algae have been employed to clean up various environmental pollutants. This review discusses the types, mechanisms, and factors affecting microbial bioremediation. It also recommends possible steps that could be taken to promote the use of microbes as bioremediation agents.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47210003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Biodegradable plastic mulch films increase yield and promote nitrogen use efficiency in organic horticulture","authors":"Martin Samphire, D. Chadwick, Davey L. Jones","doi":"10.3389/fagro.2023.1141608","DOIUrl":"https://doi.org/10.3389/fagro.2023.1141608","url":null,"abstract":"Plastic film mulches (PFM) are used extensively due to their ability to increase yield and suppress weed emergence. Their effects on plant-soil-microbial interactions, however, are less well understood. Organic systems rely on the supply of nutrients from organic sources (e.g., manures and fertility-building leys) and where poor N availability often limits yield. The issue is compounded by horticultural crops (e.g., lettuce) with a high N demand, but which are inefficient at recovering N from soil. The effect of PFM on the mineralisation of organic fertilisers and its interaction with other agronomic factors such as planting density is also less well-researched. We hypothesised that biodegradable PFM would be a useful tool to increase the efficiency of N management in organic horticulture by increasing the supply of available N leading to increased crop N uptake and crop yield, and simultaneously reducing N losses during the growing season. We conducted two field experiments under a temperate maritime climate with lettuces grown with either conventional (LDPE) PFM or a polylactic acid-based biodegradable PFM alongside un-mulched controls. The first experiment involved black or white coloured PFMs and two planting densities while the second experiment involved treatments with and without addition of poultry manure. Overall, yields were increased by 39% in both experiments with PFM, while soil mineral N concentrations were up to 5 times higher with PFM than without. Measurements of soil organic matter (SOM) turnover (Tea Bag Index) and soil CO2 efflux indicated a more rapid decay of SOM in the presence of the PFM. The use of PFM also promoted N use efficiency (NUE) by 300% in the presence of poultry manure. Denser planting with PFM resulted in proportionately higher yields. Higher yield and higher N concentrations (5-10%) in crop tissue in mulched plots resulted in higher total N uptake, however, total N uptake was low compared to soil concentrations: mulching with biodegradable PFM resulted in higher residual mineral N than un-mulched plots (77-147 mg kg-1 vs. 19 -70 mg kg-1). Our results are consistent with reduced N losses to the environment during the growing season and increased mineralisation under PFM. In conclusion, our findings support the adoption of PFM for organic horticulture and show that biodegradable PFM perform similarly to LDPE-based PFMs.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42876697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of cultivar and inoculant on yields of faba beans (Vicia faba minor) and subsequent spring wheat (Triticum aestivum) under Scandinavian cropping conditions","authors":"F. Fogelberg, Johanna Östlund, Å. Myrbeck","doi":"10.3389/fagro.2023.1179996","DOIUrl":"https://doi.org/10.3389/fagro.2023.1179996","url":null,"abstract":"Inoculation of legumes is generally considered to increase yield and to lower the need of nitrogen (N) fertilization, especially in semiarid regions and on sandy soils. It has not been clear whether inoculation with Rhizobium sp. in cropping of faba beans (Vicia faba minor) under Swedish conditions would improve yield and protein content. In 2015–2016, three faba bean cultivars and two strains of Rhizobium were studied in field trials in Central Sweden, including analyses of N fixation capacities using 15N abundance. The study did not show any effects of inoculation of Rhizobium on yield or protein content of faba beans or subsequent spring wheat yields. Yields of faba beans varied between cultivars but were not connected to inoculation. 15N abundance was influenced by rhizobium. The study cannot support the opinion that, generally, inoculation is beneficial for improved outcome of faba bean cropping under Scandinavian field conditions. No residual effect of inoculation on subsequent spring wheat yield was found.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48119930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gift Chawanda, Y. Tembo, T. Donga, V. Kabambe, P. Stevenson, S. Belmain
{"title":"Agroecological management of fall armyworm using soil and botanical treatments reduces crop damage and increases maize yield","authors":"Gift Chawanda, Y. Tembo, T. Donga, V. Kabambe, P. Stevenson, S. Belmain","doi":"10.3389/fagro.2023.1114496","DOIUrl":"https://doi.org/10.3389/fagro.2023.1114496","url":null,"abstract":"Introduction Fall armyworm continues to disrupt smallholder farming systems across sub-Saharan Africa, with sporadic outbreaks and chronic cereal crop losses. Smallholders have been adapting to the pest by increasing crop surveillance for targeted control measures and developing low-cost solutions. For example, some report placing soil or ash in maize whorls where the mechanism of pest control may be suffocation, abrasion leading to desiccation, or through the introduction of soil-borne entomopathogens. Methods To verify the efficacy of this approach we evaluated different soil types on maize infested with fall armyworm to assess their efficacy. We also evaluated the efficacy of pesticidal plant species, powdered and placed in leaf whorls to control fall armyworm. Results and discussion Different United States Department of Agriculture-characterised soil types (sand, loam, clay) and wood ash were effective in reducing the number of larvae and maize leaf damage by approximately 50%. Maize yield with the synthetic control (chlorpyriphos) was 13,700 kg/ha, which was 42% higher than the untreated control (7,900 kg/ha). Soil and ash treatments yields between 10,400 to 12,400 kg/ha were 24-36% higher than the untreated control. Dry soil applied after watering was most effective regardless of soil type. However, wet soil treatments applied before watering were also highly effective in reducing the number of fall armyworm larvae and reducing insect damage to maize leaves. Botanical powders from Azadirachta indica, Nicotiana tabacum, Cymbopogon citratus and Lippia javanica were also effective when applied to maize leaf whorls. Plant powder treatments and water extracts were significantly effective in reducing the number of larvae and leaf damage. The highest yield obtained with botanicals was observed with A. indica powder (5,600 kg/ha), C. citratus extract (5,800 kg/ha) and N. tabacum extract (5,800 kg/ha), where the synthetic treatment yield was 6,900 kg/ha and the untreated yield was 1,700 kg/ha. We conclude that smallholder farmer innovations in managing fall armyworm are effective low-cost options. Scientific validation of soil treatments and botanicals should help increase the confidence of policy makers and allow knowledge extension services to recommend their use to smallholder farmers, which in turn may reduce reliance on imported synthetic pesticides and improve farmer resilience, circular economies and human and environmental health.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46123883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Dissanayaka, D. Dissanayake, S. Udumann, T. Nuwarapaksha, A. Atapattu
{"title":"Agroforestry—a key tool in the climate-smart agriculture context: a review on coconut cultivation in Sri Lanka","authors":"D. Dissanayaka, D. Dissanayake, S. Udumann, T. Nuwarapaksha, A. Atapattu","doi":"10.3389/fagro.2023.1162750","DOIUrl":"https://doi.org/10.3389/fagro.2023.1162750","url":null,"abstract":"Long-term monoculture of coconuts has resulted in several land-use-related concerns, such as decreasing land productivity, degraded soil, and ineffective resource utilization on a local and global level. Modifying traditional coconut farming with agroforestry concepts is a well-suited predominant nature-based solution for Sri Lanka as well as for other coconut-growing countries to achieve environmental, social, and economic benefits. By intentionally and intensively integrating annual and perennial plants with farm animals in a dynamic and interactive manner, this land-use system creates a sustainable harmonious mini-ecosystem with landscape restoration. Agroforestry mixed with coconut cultivation decreases the risk of crop failure, generates additional income sources, and balances the ecosystem functions by increasing species richness, enhancing soil physical, biological, and chemical properties, opening new carbon sequestration pathways, purifying air and water sources, and being an excellent feedstock source for bioenergy generation. This environmentally friendly farming will promote the Kyoto Protocol and lessen global warming by limiting the atmospheric buildup of greenhouse gases. A proper and accurate plan is required to implement a successful and profitable long-lived coconut-based agroforestry system. The objective of this paper is to recognize the various agroforestry concepts applicable to coconut-based farming, highlight the wide range of benefits and ecosystem services that can be gained through in-situ and ex-situ agroforestry practices, and explore the challenges that may arise during the integration of agroforestry techniques into a coconut-based farming system. Graphical Abstract","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42829916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Amalin, M. Arcelo, B. J. M. Almarinez, Rhodina C. Castillo, J. Legaspi, Kris Lord T. Santos, M. Tavera, J. Janairo, A. Zhang
{"title":"Field evaluation of the sex pheromone of the cacao pod borer (Conopomorpha cramerella Snellen) in the Philippines","authors":"D. Amalin, M. Arcelo, B. J. M. Almarinez, Rhodina C. Castillo, J. Legaspi, Kris Lord T. Santos, M. Tavera, J. Janairo, A. Zhang","doi":"10.3389/fagro.2023.1165299","DOIUrl":"https://doi.org/10.3389/fagro.2023.1165299","url":null,"abstract":"Cacao is a promising high-value crop in the Philippines and is considered one of the key players globally in providing the raw materials for chocolate making. However, before the Philippines can take this market opportunity, production constraints from various pests should be addressed. The cacao pod borer (CPB), Conopomorpha cramerella, is one of the major insect pests of cacao in the Philippines, which can cause up to 50% annual loss or even higher if proper management is not employed. Management of CPB heavily relies on chemical control but is becoming unpopular because of its high cost and health risk to people and the environment. A number of efforts have been made to develop sex pheromones to monitor and control CPB. A field bioassay of the new blend of CPB sex pheromones was conducted in southern Philippines to determine its efficiency and identify the appropriate trap height placement in a cacao field, which is important in maximizing the efficiency of the sex pheromone traps for inclusion in the integrated pest management (IPM) program of CPB. Pheromone lures at four different trap heights (1.0 m, 0.5 m above the canopy, 0.0 m or along the canopy, and 0.5 m below the canopy) and a blank lure (control) placed 1.0 m above the canopy were evaluated in terms of male CPB trap catches. Results showed significantly higher male CPB trap catches when installed at least 0.5 m above the canopy while minimal to zero male CPB catches were obtained from the control traps with blank lures, confirming the attractiveness of the new blend of the CPB sex pheromone in the field. This suggests the reliability of the pheromone-based method to monitor and control CPB and as a major component of the IPM program.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43033086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Model-based assessment of biomass incorporation to mitigate nitrogen losses from arable fields in Central Europe","authors":"S. Rothardt, H. Kage","doi":"10.3389/fagro.2023.1155187","DOIUrl":"https://doi.org/10.3389/fagro.2023.1155187","url":null,"abstract":"Nitrogen (N) loss by leaching is a major concern in common crop rotations in Central Europe due to high post-harvest soil mineral N, low N uptake in autumn/winter, and percolation. This can lead to eutrophication of water bodies and indirect greenhouse gas emissions. One potential solution is to control microbial immobilization through the incorporation of organic matter. To examine the effectiveness of this approach, we compared the incorporation of crop residues from winter oilseed rape, faba beans, and winter wheat with the application of sawdust in a field-scale experiment. Field observations of the impact on autumn/winter N-dynamics were supplemented with model-derived parameters. Our results showed that the incorporation of crop residues significantly reduced autumn net mineralization in topsoil, with the largest reduction seen with cereal straw. However, the temporal dynamics of the effect did not meet the desired time frame, and the impact on N leaching was low. Field data, modeling processes, and a theoretical amendment assessment suggested that resistant organic matter accumulated under the given environmental conditions, probably resulting in a long-term effect on nutrient dynamics. In conclusion, incorporating crop residues from the preceding crop is the best option to date for mitigating post-harvest N losses and improving soil health with minimal crop management effort. However, controlling microbial immobilization through organic matter incorporation can be a useful measure whose effectiveness depends on the amendment used and field conditions.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41408510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Tavera, M.C. Dela Cruz, Kris Lord T. Santos, D. Amalin, J. Janairo
{"title":"β-caryophyllene as an attractant for the cacao mirid bug, Helopeltis bakeri Poppius (Hemiptera: Miridae), and chemodiversity of its host plant volatiles","authors":"M. Tavera, M.C. Dela Cruz, Kris Lord T. Santos, D. Amalin, J. Janairo","doi":"10.3389/fagro.2023.1178558","DOIUrl":"https://doi.org/10.3389/fagro.2023.1178558","url":null,"abstract":"The cacao mirid bug, Helopeltis bakeri, is a major insect pest of cacao in the Philippines. It feeds on pods causing puncture wounds that become necrotic lesions and may lead eventually to pod abortion. There is currently no semiochemical-based system developed for the monitoring and control of H. bakeri. Here, we report a kairomone identified from host plants of H. bakeri as a potential attractant. Volatile components were extracted using solid-phase microextraction (100-µm polydimethylsiloxane) and analyzed by gas chromatography - mass spectrometry. Chemodiversity analysis considering compound richness, evenness, and disparity showed similar phytochemical diversity among the six host plants, suggesting that chemodiversity is a factor in the host selection behavior of H. bakeri. Comparison of volatiles revealed that β-caryophyllene was present in all host plants. Using a wind tunnel, an impregnated lure containing 90 µg β-caryophyllene showed the highest attraction to adult H. bakeri. The results show the potential of β-caryophyllene as attractant that can be used in the development of kairomone-based trapping systems for H. bakeri as part of a holistic integrated pest management system for cacao.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47114240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nolwenn Kergosien, V. Stiger-Pouvreau, S. Connan, F. Hennequart, J. Brébion
{"title":"Mini-Review: brown macroalgae as a promising raw material to produce biostimulants for the agriculture sector","authors":"Nolwenn Kergosien, V. Stiger-Pouvreau, S. Connan, F. Hennequart, J. Brébion","doi":"10.3389/fagro.2023.1109989","DOIUrl":"https://doi.org/10.3389/fagro.2023.1109989","url":null,"abstract":"The worldwide growing food demand and the excessive use of synthetic and chemical inputs compel the agricultural sector to find innovative and sustainable solutions to enhance or at least maintain crop yields in times of increased abiotic stresses levels linked to global change. Currently, great research efforts are carried out on brown seaweeds as their environment lead them to produce a broad range of compounds, with osmoregulatory, antioxidant, pro-bacterial, and plant-growth promoting activities. Indeed, numerous studies are looking at different combinations of algal species, extraction processes, plant species and environments of plant culture to highlight the various effects of algal extracts on plant growth and development, and resistance to abiotic stresses. Consequently, a wide variety of novel commercial products are emerging, presenting diversified chemical compositions, formulations and means of application. Such products allow the biostimulation of plants and soil by alleviating abiotic stresses such as drought, frost, and salt. The action of brown macroalgal extracts on plant and soil health has been repeatedly demonstrated, yet the precise relation between the extract chemical composition and its subsequent effect is still to be elucidated, as molecular synergy is suspected to play an important role. In this review, we present the interest of using brown macroalgal extracts to produce biostimulants with beneficial action on soil health, plant growth and development, as well as resistance against abiotic stresses, in relation to the molecular changes occurring.","PeriodicalId":34038,"journal":{"name":"Frontiers in Agronomy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42719765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}