Topic Editors

Mountain Research Centre (CIMO), Polytechnic Institute of Bragança (IPB), 5300-253 Bragança, Portugal
Departamento de Biologia e Ambiente, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Padua, Italy
Department of Agricultural and Environmental Sciences, University of Milano, via Celoria 2, 20133 Milano, Italy

Biostimulants in Agriculture

Abstract submission deadline
closed (31 March 2023)
Manuscript submission deadline
closed (31 May 2023)
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51408

Topic Information

Dear Colleagues,

Plant biostimulants are substances or microorganisms applied to plants, soils or seeds with the aim of enhancing crop yield, quality traits, plant tolerance to a wide range of biotic and abiotic stresses and/or nutrient use efficiency. The beneficial effects of plant biostimulants are usually not due to their nutrient content but to regulatory effects on the plant’s metabolism. Biostimulants are known to elicit positive plant responses at lower doses than traditional fertilizers. Some of the substances with the greatest abundance and diversity in the markets are humic substances (humic and fulvic acids), free amino acids, seaweed extracts, inorganic compounds and beneficial microorganisms (fungi and bacteria). An important source of biostimulants are waste streams, which places these products in the spotlight for agricultural innovations directed toward achieving a circular economy.

The market of plant biostimulants has been rapidly growing. The use of plant biostimulants has allowed the concept of ecological intensification to be developed. There is an awareness that agricultural productivity cannot decrease in the face of the need to feed a world population that continues to grow but, instead, must be increased by improving nutrient use efficiency and reducing the use of conventional fertilizers and other external inputs.

Research on plant biostimulants is gaining increasing attention among scientists. The list of scientific publications and reviews on the subject to date is considerable. Science has focused on the need to elucidate the modes of action, namely their impact at the molecular, cellular and/or whole-plant level, taking into account the complexity of substances that are used as plant biostimulants.

Although science has been doing a remarkable job, the information available for farmers to make their decisions remains vastly insufficient. Producers are encouraged to use these plant biostimulants due to the general positive publicity that comes from the science and the advertising of the companies that have put them on the market. However, there is a lack of data with the necessary detail to allow farmers to be able to use them safely and with some guarantee that they will obtain a return on their investment. Thus, for this Special Issue we intend to select a set of studies oriented toward the end users (the farmers) that can guide them in making decisions about these production factors entailing a cost that they have to bear. Field, greenhouse or hydroponic experiments are preferred in which the conditions are as close as possible to those used by farmers, which may also include examining drought, salt, low temperature and/or other stress conditions. So long as the experimental conditions and consistency in the results are duly established, studies that show positive, nonsignificant or negative responses of plants to the application of plant biostimulants will be equally considered.

Prof. Dr. Manuel Ângelo Rosa Rodrigues
Prof. Dr. Carlos M. Correia
Dr. Paolo Carletti
Prof. Dr. Antonio Ferrante
Topic Editors

Keywords

  •  plant biostimulants
  •  protein hydrolysates
  •  humic and fulvic acids
  •  seaweed extracts
  •  chitin and chitosan derivatives
  •  inorganic compounds
  •  beneficial microorganisms

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Agriculture
agriculture
3.3 4.9 2011 20.2 Days CHF 2600
Agronomy
agronomy
3.3 6.2 2011 15.5 Days CHF 2600
Crops
crops
- - 2021 24.2 Days CHF 1000
Horticulturae
horticulturae
3.1 3.5 2015 14.8 Days CHF 2200
Plants
plants
4.0 6.5 2012 18.2 Days CHF 2700

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Published Papers (19 papers)

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26 pages, 929 KiB  
Review
An Overview of Biostimulants’ Effects in Saline Soils
by Abdelbasset Lakhdar, Mohamed Trigui and Francesco Montemurro
Agronomy 2023, 13(8), 2092; https://doi.org/10.3390/agronomy13082092 - 9 Aug 2023
Cited by 6 | Viewed by 2391
Abstract
The unsustainable use of natural resources and their overexploitation continue to be major threats to global agriculture development. This practice increases the abiotic stresses, resulting both in crop yield losses and soil degradation. Low productivity is often associated with salinized soil, which is [...] Read more.
The unsustainable use of natural resources and their overexploitation continue to be major threats to global agriculture development. This practice increases the abiotic stresses, resulting both in crop yield losses and soil degradation. Low productivity is often associated with salinized soil, which is caused by the toxic and osmotic effects of soluble salt accumulation and, consequently, lack of organic matter. Conversely, there is a need to improve the current crop productivity to meet the increasing food demands. Among the current methodologies proposed to increase plant resistance to abiotic stress, the utilization in crop production of plant biostimulants has been recently proposed. These are organic products mainly based on algae, microorganisms, fulvic and humic acids, proteins, and amino acids that improve physiological plant performance, leading to increased crop productivity. Among their positive benefits, the application of plant biostimulants can also reduce the usage of conventional chemical fertilizers. The aim of this work was to present the effects of different biostimulants on saline conditions. In particular, in this review, we report and critically discuss the most recent research dealing with the effects of the application of plant biostimulants both on crop growth and on plant salinity resistance. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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14 pages, 1866 KiB  
Article
Biostimulants in Corn Cultivation as a Means to Alleviate the Impacts of Irregular Water Regimes Induced by Climate Change
by Gabriel Luiz Piati, Sebastião Ferreira de Lima, Renato Lustosa Sobrinho, Osvaldir Feliciano dos Santos, Eduardo Pradi Vendruscolo, Janaina Jacinto de Oliveira, Tassila Aparecida do Nascimento de Araújo, Khairiah Mubarak Alwutayd, Taciane Finatto and Hamada AbdElgawad
Plants 2023, 12(13), 2569; https://doi.org/10.3390/plants12132569 - 7 Jul 2023
Viewed by 1523
Abstract
Climate change alters regular weather seasonality. Corn is one of the main crops affected by irregular water regimes. Due to complications in decision-making processes related to climate change, it is estimated that planting corn outside the optimal window results in around USD 340 [...] Read more.
Climate change alters regular weather seasonality. Corn is one of the main crops affected by irregular water regimes. Due to complications in decision-making processes related to climate change, it is estimated that planting corn outside the optimal window results in around USD 340 million in losses per year in the United States’ Corn Belt. In turn, exogenous plant growth regulators have been gaining prominence due to their potential to positively influence the morphology and physiology of plants under stress. This study was based on the hypothesis that the use of plant growth regulators can assist in mitigating the adverse effects of climate change on corn plants sown both inside and outside the recommended planting period. In this context, the effects of biostimulant application on gas exchange in corn plants sown within and outside the recommended period were evaluated. The experiment was carried out in randomized blocks in a 4 × 5 × 2 factorial scheme with four repetitions. These were four sowing times, the application of the biostimulants via seeds in five doses, and foliar applications (presence and absence). The biostimulant doses were 0.00, 6.25, 12.50, 18.75, and 25 mL kg−1. The foliar application used a dose of 500 mL ha−1. Only in the period (2017/2) higher doses of biostimulants indicated a decrease in the water use efficiency of plants, suggesting the need to evaluate this variable carefully. In this regard, future studies may investigate the ideal doses and application timings of biostimulants for different edaphoclimatic conditions. In general, the combined use of biostimulants on seeds and as a foliar treatment boosted physiological activity and stimulated photosynthetic processes in corn plants. Based on these data, plant regulators can be a useful tool to mitigate the adverse effects of climate change on corn plants sown inside and outside the planting period. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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16 pages, 1622 KiB  
Article
Effect of Glutamic Acid and 6-benzylaminopurine on Flower Bud Biostimulation, Fruit Quality and Antioxidant Activity in Blueberry
by María Itzel Pérez-León, José Antonio González-Fuentes, Luis Alonso Valdez-Aguilar, Adalberto Benavides-Mendoza, Daniela Alvarado-Camarillo and Carlos Estuardo Castillo-Chacón
Plants 2023, 12(12), 2363; https://doi.org/10.3390/plants12122363 - 18 Jun 2023
Cited by 2 | Viewed by 2047
Abstract
Blueberry is a highly demanded and consumed fruit due to its beneficial effects on human health, because of its bioactive compounds with a high antioxidant capacity. The interest in increasing the yield and quality of blueberries has led to the application of some [...] Read more.
Blueberry is a highly demanded and consumed fruit due to its beneficial effects on human health, because of its bioactive compounds with a high antioxidant capacity. The interest in increasing the yield and quality of blueberries has led to the application of some innovative techniques such as biostimulation. The objective of this research was to assess the effect of the exogenous application of glutamic acid (GLU) and 6-benzylaminopurine (6-BAP) as biostimulants on flower bud sprouting, fruit quality, and antioxidant compounds in blueberry cv. Biloxi. The application of GLU and 6-BAP positively affected bud sprouting, fruit quality, and antioxidant content. The application of 500 and 10 mg L−1 GLU and 6-BAP, respectively, increased the number of flower buds, while 500 and 20 mg L−1 generated fruits with higher content of flavonoids, vitamin C, and anthocyanins and higher enzymatic activity of catalase and ascorbate peroxidase enzymes. Hence, the application of these biostimulants is an effective way to enhance the yield and fruit quality of blueberries. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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17 pages, 16315 KiB  
Article
Integrated Transcriptome and Metabolome Analysis Reveal That Exogenous Gibberellin Application Regulates Lignin Synthesis in Ramie
by Hongdong Jie, Long Zhao, Yushen Ma, Adnan Rasheed and Yucheng Jie
Agronomy 2023, 13(6), 1450; https://doi.org/10.3390/agronomy13061450 - 24 May 2023
Cited by 3 | Viewed by 1329
Abstract
Gibberellin regulates plant growth, development, and metabolic processes. However, the underlying mechanism of the substantial effect of gibberellin on stem height and secondary metabolites in forage ramie is unclear. Therefore, this study combined transcriptomic and metabolomics analyses to identify the mechanisms regulating growth [...] Read more.
Gibberellin regulates plant growth, development, and metabolic processes. However, the underlying mechanism of the substantial effect of gibberellin on stem height and secondary metabolites in forage ramie is unclear. Therefore, this study combined transcriptomic and metabolomics analyses to identify the mechanisms regulating growth and secondary metabolite contents in forage ramie following exogenous gibberellin application. Exogenous gibberellin application significantly reduced the lignin content in the leaves but not in the stems. At the same time, gibberellin significantly increased the total flavonoid and chlorogenic acid contents in both the stems and leaves. In addition, 293 differentially expressed genes (DEGs) and 68 differentially expressed metabolites (DEMs) were identified in the leaves. In the stems, 128 DEGs and 41 DEMs were identified. The DEGs PER42, FLS, CYP75A, and PNC1 were up-regulated in the leaves, affecting phenylpropane metabolism. The joint analysis of the DEMs and DEGs revealed that the changes in the DEGs and DEMs in the leaves and stems improved the substrate efficiency in the phenol propane pathway and inhibited lignin synthesis in plants, thus shifting to flavonoid pathway synthesis. In conclusion, gibberellin treatment effectively reduces the lignin content in forage ramie while increasing the flavonoid and chlorogenic acid contents. These findings provide empirical and practical guidance for breeding for forage quality in ramie and the improvement and cultivation control of forage ramie. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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15 pages, 2127 KiB  
Article
Outcome of Microalgae Biomass Application on Seed Germination and Hormonal Activity in Winter Wheat Leaves
by Lamnganbi Mutum, Tibor Janda, Éva Darkó, Gabriella Szalai, Kamirán Áron Hamow and Zoltán Molnár
Agronomy 2023, 13(4), 1088; https://doi.org/10.3390/agronomy13041088 - 10 Apr 2023
Cited by 1 | Viewed by 1784
Abstract
The present work aimed to test selected microalgae strains from the Mosonmagyaróvár Algae Culture Collection (MACC) on germination ability and certain physiological processes in winter wheat (Triticum aestivum L.) plants. Germination tests showed substantial differences between the strains, meaning that certain strains [...] Read more.
The present work aimed to test selected microalgae strains from the Mosonmagyaróvár Algae Culture Collection (MACC) on germination ability and certain physiological processes in winter wheat (Triticum aestivum L.) plants. Germination tests showed substantial differences between the strains, meaning that certain strains (such as MACC-430, MACC-612, MACC-922) improved the germination processes while others performed worse (MACC-438, MACC-755) than the control in a concentration-dependent manner. The germination index of seeds treated with MACC-430 @ 1 g L−1 concentrations was 87, while that of the control was 45. The mungbean rooting bioassay proves that microalgae biomass may exhibit auxin-like activity, especially in strain MACC-612 (Nostoc sp.), which was characterized by the highest endogenous level of plant growth regulator indole-3-acetic-acid among the selected strains. Foliar spray on the leaves of developed plants did not significantly alter the photosynthetic processes, but it influenced the secondary metabolite composition. After the application of microalgae biomass, there were also changes in plant hormones, including salicylic acid, abscisic acid, and jasmonic acid-leucine/isoleucine conjugate compositions, which play a role in plant stress signaling in plants. A decrease in indole-3-acetic acid was also observed in the Mv Nádor cultivar. These results suggest that the application of certain microalgae strains can be used effectively to improve the germination of wheat seeds, and as a foliar spray, they may also modify the acclimation processes in a genotype-dependent way. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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17 pages, 3114 KiB  
Article
Endophytic Biostimulants for Smart Agriculture: Burkholderia seminalis 869T2 Benefits Heading Leafy Vegetables In-Field Management in Taiwan
by Shih-Hsun Walter Hung, Tsai-Ching Huang, Yu-Chih Lai, I-Chen Wu, Chia-Ho Liu, Yuh-Feng Huarng, Hau-Hsuan Hwang, En-Pei Isabel Chiang, Chih-Horng Kuo and Chieh-Chen Huang
Agronomy 2023, 13(4), 967; https://doi.org/10.3390/agronomy13040967 - 24 Mar 2023
Cited by 2 | Viewed by 2640
Abstract
Heading leafy vegetables (HLVs) are essential horticultural crops that feed many people worldwide. An increasing global population demands more cropping systems, leading to stresses such as fertilizer overuse and soil salination, decreasing in crop productivity and agricultural sustainability. Hence, developing those eco-friendly farming [...] Read more.
Heading leafy vegetables (HLVs) are essential horticultural crops that feed many people worldwide. An increasing global population demands more cropping systems, leading to stresses such as fertilizer overuse and soil salination, decreasing in crop productivity and agricultural sustainability. Hence, developing those eco-friendly farming strategies that could simultaneously reduce fertilizer usage and increase crop harvest is urgent for agriculture. An endophytic bacterium Burkholderia seminalis 869T2 with pyrroloquinoline quinone (PQQ) producing ability were applied as biostimulant for vegetable seedlings under greenhouse or field conditions. Two globally important HLVs, cabbage and head lettuce, were preliminarily tested, and further examinations under in-field farming during two different seasons were carried out to develop an endophytic biostimulants (EBs)-assisted lettuce production system. In this study, we confirmed that B. seminalis 869T2 is versatile EBs for HLVs, which significantly promote plant growth and enhance the qualities of crops by increasing the harvested head weight, size and nutrient composition. Nevertheless, the harvest was accelerated by two weeks, together with higher product qualities and 50% fertilizing cost savings per hectare. Our study provides an in-field EBs-assisted management for lettuce production that could decrease costs and increase the product’s value. The results highlight the importance of endophytic bacteria that deserve further investigation due to their enigmatic symbiotic relationships with their hosts and potential usage in the agro-industry. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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17 pages, 2288 KiB  
Article
Biostimulation Effects of Seaweed Extract (Ascophyllum nodosum) on Phytomorpho-Physiological, Yield, and Quality Traits of Tomato (Solanum lycopersicum L.)
by Lakshmi Subramaniyan, Ravichandran Veerasamy, Jeyakumar Prabhakaran, Anandakumar Selvaraj, Senthil Algarswamy, Kalarani M. Karuppasami, Kalaiselvi Thangavel and Sakthivel Nalliappan
Horticulturae 2023, 9(3), 348; https://doi.org/10.3390/horticulturae9030348 - 7 Mar 2023
Cited by 6 | Viewed by 2653
Abstract
Biostimulants are innovative organic tools, which promote the growth, plant development, production, and quality of various crops without harming the environment; however, the effects of biostimulants on the production of tomato needed to be explored further under open field conditions. Based on this [...] Read more.
Biostimulants are innovative organic tools, which promote the growth, plant development, production, and quality of various crops without harming the environment; however, the effects of biostimulants on the production of tomato needed to be explored further under open field conditions. Based on this view, this study’s objective was to assess the impact of Kendal Root, a biostimulant-containing seaweed, Ascophyllum nodosum, and plant extracts on the phytomorpho-physiological, yield, and quality of tomato. Three doses of Kendal Root (2.5, 5.0, and 10 L ha−1) were given as soil drenching, and the results were compared with control. Generally, the Kendal Root treatments positively improved the growth, physiological, yield, and quality attributes of tomato. However, among the three different concentrations, Kendal Root 5.0 L ha−1 significantly improved the plant growth and physiological aspects of tomato, such as plant height, leaf area, shoot and root dry weight, SPAD value, and gas exchange parameters. Considering the yield traits, the Kendal Root 5.0 L ha−1 application significantly improved the tomato fruit number, yield per plant, and yield per hectare. Conversely, flower number per plant and average fruit weight was not remarkably improved by Kendal Root 5.0 L ha−1. Moreover, Kendal Root 5.0 L ha−1 positively improved the quality traits of tomato, including total soluble solids, ascorbic acid content, lycopene, and total sugars than the titratable acidity content of tomato fruits. Hence, the integration of Kendal Root biostimulant in tomato production could be an effective way to boost plant growth, production, and quality of tomato. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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15 pages, 2011 KiB  
Article
Organo Mineral Fertilizers Increases Vegetative Growth and Yield and Quality Parameters of Pomegranate cv. Wonderful Fruits
by Annalisa Tarantino, Grazia Disciglio, Laura Frabboni and Giuseppe Lopriore
Horticulturae 2023, 9(2), 164; https://doi.org/10.3390/horticulturae9020164 - 27 Jan 2023
Cited by 2 | Viewed by 1794
Abstract
In recent years, to improve sustainable production in horticultural crops, many new types of strategies have been developed, including organo-mineral fertilization to complement chemical fertilizers in order to enhance the nutritional status of plants and sustainability of the agroecosystems. This study was performed [...] Read more.
In recent years, to improve sustainable production in horticultural crops, many new types of strategies have been developed, including organo-mineral fertilization to complement chemical fertilizers in order to enhance the nutritional status of plants and sustainability of the agroecosystems. This study was performed on a young pomegranate orchard of the “Wonderful” cultivar during the 2018 and 2019 seasons. The purpose was to evaluate the effects of three foliar applications (at the red ball, fruit setting, and fruit development stages) of four commercial organo-mineral fertilizers (Hendophyt®, Ergostim XL®, Siapton® 10L, and Allibio Rad®) on vegetative growth, yield, and several other physico-chemical parameters of the fruits, throughout each season. The results obtained showed several differences between the two years. The annual trunk growth of trees under all compared treatments showed significantly lower values in 2018 (average 9.7 mm) than in 2019 (average 11.8 mm). At the end of the two-year period, the biostimulant treatments resulted in significantly larger trunk diameters (average 43.6 mm) than the control (39.6 mm). Only in 2018, significantly higher number of fruits per tree, number of arils per fruit, edible part, and juice yield were obtained under biostimulant treatments compared with the control. No differences among treatments were observed for any color parameters or physico-chemical traits in the fruits for either year. In 2019, fruit morpho-pomological properties tended to be lower than in 2018, while in contrast, total phenol content and antioxidant activity were higher. The warmer and windier weather conditions of 2019 probably led to greater plant stress conditions, with a reduction in fruit size and an increase in the bioactive compounds of juice. In conclusion, due to the various positive results, foliar organo-mineral fertilizers could be recommended to improve the performance of pomegranate Wondeful cv. under similar conditions. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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17 pages, 4929 KiB  
Article
Transformation of Strawberry Plants’ Phenolic Profile after Treatment with a Mechanocomposite Based on Silicon Chelates in the Course of Development under In Vitro, Ex Vitro, and In Vivo Conditions
by Olga Kotsupiy, Evgeniya Karpova, Elena Trofimova, Tatyana Novikova and Elena Ambros
Horticulturae 2023, 9(2), 157; https://doi.org/10.3390/horticulturae9020157 - 27 Jan 2023
Cited by 2 | Viewed by 1347
Abstract
The positive effect of silicon on plants is thought to be mediated by a modification of phenolic metabolism. The purpose of the study was to evaluate the effect of a silicon-based mechanocomposite (MC) on alterations of the phenolic profile of strawberry plants in [...] Read more.
The positive effect of silicon on plants is thought to be mediated by a modification of phenolic metabolism. The purpose of the study was to evaluate the effect of a silicon-based mechanocomposite (MC) on alterations of the phenolic profile of strawberry plants in the course of development under in vitro, ex vitro, and in vivo conditions. Aqueous ethanol extracts of aboveground parts of in vitro–derived plants (Fragaria × ananassa cv. ‘Solnechnaya polyanka’) were subjected to HPLC. Nineteen individual phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, catechins, ellagic acid derivatives, and flavonol glycosides) were quantified. The results revealed phenolic profiles specific to each studied stage and significant transformations of the profiles by the MC. It induced strong upregulation of hydroxycinnamic acid during in vitro rooting and of catechins and hydroxybenzoic acids during ex vitro acclimation. At ex vitro and in vivo stages, the emergence of quercetin glycosides and ellagitannins was registered, and the MC elevated their levels during ex vitro acclimation and field growth. Principal component analysis confirmed the significant effect of the MC on the phenolic profile at all stages, and this effect was the strongest during ex vitro acclimation. The results are consistent with previous reports on the modification of phenolic profiles of plants by silicon-derived biostimulants. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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19 pages, 3382 KiB  
Review
Encapsulation with Natural Polymers to Improve the Properties of Biostimulants in Agriculture
by David Jíménez-Arias, Sarai Morales-Sierra, Patrícia Silva, Henrique Carrêlo, Adriana Gonçalves, José Filipe Teixeira Ganança, Nuno Nunes, Carla S. S. Gouveia, Sónia Alves, João Paulo Borges and Miguel Â. A. Pinheiro de Carvalho
Plants 2023, 12(1), 55; https://doi.org/10.3390/plants12010055 - 22 Dec 2022
Cited by 11 | Viewed by 4879
Abstract
Encapsulation in agriculture today is practically focused on agrochemicals such as pesticides, herbicides, fungicides, or fertilizers to enhance the protective or nutritive aspects of the entrapped active ingredients. However, one of the most promising and environmentally friendly technologies, biostimulants, is hardly explored in [...] Read more.
Encapsulation in agriculture today is practically focused on agrochemicals such as pesticides, herbicides, fungicides, or fertilizers to enhance the protective or nutritive aspects of the entrapped active ingredients. However, one of the most promising and environmentally friendly technologies, biostimulants, is hardly explored in this field. Encapsulation of biostimulants could indeed be an excellent means of counteracting the problems posed by their nature: they are easily biodegradable, and most of them run off through the soil, losing most of the compounds, thus becoming inaccessible to plants. In this respect, encapsulation seems to be a practical and profitable way to increase the stability and durability of biostimulants under field conditions. This review paper aims to provide researchers working on plant biostimulants with a quick overview of how to get started with encapsulation. Here we describe different techniques and offer protocols and suggestions for introduction to polymer science to improve the properties of biostimulants for future agricultural applications. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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19 pages, 3894 KiB  
Review
Plant Growth Promoting Filamentous Fungi and Their Application in the Fertilization of Pastures for Animal Consumption
by Rosalba Argumedo-Delira, Mario J. Gómez-Martínez and Jairo Mora-Delgado
Agronomy 2022, 12(12), 3033; https://doi.org/10.3390/agronomy12123033 - 30 Nov 2022
Cited by 7 | Viewed by 5205
Abstract
The diversity of fungi in different terrestrial and aquatic ecosystems has made it possible to explore their use as important tools in promoting plant growth and in managing plant diseases given their high potential to replace the use of synthetic chemical products (fertilizers [...] Read more.
The diversity of fungi in different terrestrial and aquatic ecosystems has made it possible to explore their use as important tools in promoting plant growth and in managing plant diseases given their high potential to replace the use of synthetic chemical products (fertilizers and pesticides). Therefore, this review compiles information on the use of filamentous fungi in promoting plant growth, highlighting the most studied fungal genera for this purpose, such as Trichoderma, Penicillum, and Aspergillus. In addition, information is compiled on the promotion of forage grass growth using filamentous fungi, which could be a sustainable and lower-cost alternative in producing pastures to help raise animals. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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24 pages, 33859 KiB  
Article
An Organic Fertilizer ‘Doped’ with a Bacillus Strain Improves Melon and Pepper Yield, Modifying the Rhizosphere Microbiome with Negligible Changes in the Bulk Soil Microbiome
by Noemí Ortiz-Liébana, Maurizio Zotti, Marcia Barquero and Fernando González-Andrés
Agronomy 2022, 12(11), 2620; https://doi.org/10.3390/agronomy12112620 - 25 Oct 2022
Cited by 3 | Viewed by 2453
Abstract
Doped compost consists of compost inoculated with Bacillus siamensis SCFB3-1 that is formulated in biochar and then mixed with the compost. The study objective was to analyze, at field scale, the effect of doped compost on the melon and pepper yield and on [...] Read more.
Doped compost consists of compost inoculated with Bacillus siamensis SCFB3-1 that is formulated in biochar and then mixed with the compost. The study objective was to analyze, at field scale, the effect of doped compost on the melon and pepper yield and on the soil microbiome, hypothesizing that the synergy between the components of doped compost confers additional benefits to the crop. Two doses of compost (2 and 5 t/ha) and two doses of the inoculant (biochar+SCFB3-1) with respect to the compost (3% and 6% w:w) were tested. The highest yield was observed for a reduced dose of mineral fertilization (NPK -20%) with a compost dose of 2 t/ha with 6% of the inoculant. Specifically, the yield increase compared with the control, which only received NPK, was a 47% increase in melon and 28% in pepper. The microbiome of the bulk soil was not modified by the doped compost, but the composition of the rhizosphere microbiome changed, increasing in the abundance of Bacillus (the inoculated strain), but also changing the relative abundance of other genera in the bacterial community. Future works will be focused on unravelling the possible effects of phytohormones on the observed results. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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15 pages, 1144 KiB  
Article
Effect of Urease Inhibitors and Nitrification Inhibitors Combined with Seaweed Extracts on Urea Nitrogen Regulation and Application
by Furong Xiao, Dongpo Li, Lili Zhang, Yandi Du, Yan Xue, Lei Cui, Ping Gong, Yuchao Song, Ke Zhang, Yiji Zhang, Yonghua Li, Jinming Zhang and Yongkun Cui
Agronomy 2022, 12(10), 2504; https://doi.org/10.3390/agronomy12102504 - 14 Oct 2022
Cited by 3 | Viewed by 1779
Abstract
In order to improve the application effect of inhibitors, the combination of seaweed extracts (SE), urease inhibitors (UIs) and nitrification inhibitors (NIs) were added to urea fertilizers for providing a theoretical basis to develop the efficient stabilized nitrogen (N) fertilizer. The combinations were [...] Read more.
In order to improve the application effect of inhibitors, the combination of seaweed extracts (SE), urease inhibitors (UIs) and nitrification inhibitors (NIs) were added to urea fertilizers for providing a theoretical basis to develop the efficient stabilized nitrogen (N) fertilizer. The combinations were tested in outdoor pots with no N fertilizer (CK) and application of urea alone (U) as control, and SE, N-butyl phosphorothioate triamine (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), 2-chloro-6-trimethylpyridine (CP), and combinations of SE with each of the three inhibitors were added to urea to make seven fertilizer prototypes. The results showed that the addition of inhibitors and SE could regulate the N transformation, enzyme activity and microbial biomass carbon (MBC) contents and significantly improve maize yield and N use efficiency (NUE) (p < 0.05). Compared with the addition of inhibitor alone, the addition of SE was beneficial to N uptake by plants at the early growth stage of maize, but reduced the inhibitors effect; DMPP + S significantly increased the maize total biomass and NUE (p < 0.05), and the grain yield, N uptake and NUE by 15.6%, 28.5% and 30.6%, respectively. Therefore, the addition of DMPP with SE to urea significantly improved yield when planting maize in loess areas. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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18 pages, 4271 KiB  
Article
Effect of Chlorella vulgaris on the Growth and Phytochemical Contents of “Red Russian” Kale (Brassica napus var. Pabularia)
by Yun Ji Park, Jai-Eok Park, To Quyen Truong, Song Yi Koo, Jae-Hyeong Choi and Sang Min Kim
Agronomy 2022, 12(9), 2138; https://doi.org/10.3390/agronomy12092138 - 8 Sep 2022
Cited by 11 | Viewed by 3467
Abstract
Kale is a prominent leafy vegetable because of its high content of bioactive compounds and various health benefits. Microalgae have been suggested as a biostimulator that can replace chemical fertilizers by enhancing crop yield and supporting soil carbon sequestration. In this study, the [...] Read more.
Kale is a prominent leafy vegetable because of its high content of bioactive compounds and various health benefits. Microalgae have been suggested as a biostimulator that can replace chemical fertilizers by enhancing crop yield and supporting soil carbon sequestration. In this study, the effect of Chlorella vulgaris as a plant biostimulant on the growth and secondary metabolite contents of “Red Russian” kale (Brassica napus var. Pabularia) with green leaves and purple veins has been demonstrated. Three Chlorella treatments were used: CS, C. vulgaris suspension; CB, C. vulgaris biomass; and CFS, filtered C. vulgaris-free supernatant. The plant growth rates, phytochemical contents, and individual glucosinolate and anthocyanin contents were determined. There was no significant difference under the CS and CB treatments, while CFS negatively influenced on kale growth with 37% reduction of dried weight. In contrast, metabolite production differed according to Chlorella treatments. Total contents of chlorophyll and carotenoid were increased by 1.57 and 1.41 folds by CS treatment, whereas total contents of phenol and flavonoids were enhanced by 1.30 and 1.22 folds by CFS treatment. Totally, seven glucosinolates and four anthocyanins were characterized and quantified individually. Notably, CFS treatment increased gluconasturtiin and all anthocyanins the most, 10.28-fold and 5.90-fold, respectively. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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13 pages, 2280 KiB  
Article
Untargeted Metabolomics to Explore the Bacteria Exo-Metabolome Related to Plant Biostimulants
by Carlos J. García, Verónica Alacid, Francisco A. Tomás-Barberán, Carlos García and Pedro Palazón
Agronomy 2022, 12(8), 1926; https://doi.org/10.3390/agronomy12081926 - 16 Aug 2022
Cited by 8 | Viewed by 2533
Abstract
The control and development of plant growth promoters is a key factor for the agro-nomy industry in its economic performance. Different genera of bacteria are widely used as natural biostimulants with the aim of enhancing nutrition efficiency, abiotic stress tolerance and/or crop quality [...] Read more.
The control and development of plant growth promoters is a key factor for the agro-nomy industry in its economic performance. Different genera of bacteria are widely used as natural biostimulants with the aim of enhancing nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of their nutrients content. However, the complete exo-metabolome of the bacteria responsible for the biostimulant effect is still unknown and needs to be investigated. Three bacteria with different biostimulant effects were studied by untargeted metabolomics in order to describe the metabolites responsible for this effect. The pentose phosphate pathway, tryptophan metabolism, zeatin biosynthesis, vitamin B6 metabolism and amino acid metabolism were the highlighted pathways related to bacteria biostimulant activity. These results are related to the plant hormones biosynthesis pathway for auxins and zeatins biosynthesis. Fourteen metabolites were identified as biomarkers of the biostimulant activity. The results suggest a greater relevance of auxins than cytokinin pathways due the importance of the precursors identified. The results show a clear trend of using indole-3-pyruvate and 3-Indoleglycolaldehyde pathways to produce auxins by bacteria. The results demonstrate for the first time that 4-Pyridoxic acid, the fructosamines N-(1-Deoxy-1-fructosyl)phenylalanine and N-(1-Deoxy-1-fructosyl)isoleucine and the tripeptides diprotin A and B are metabolites related to biostimulant capabilities. This study shows how untargeted metabolomic approaches can be useful tools to investigate the bacteria exo-metabolomes related to biostimulant effects. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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11 pages, 1483 KiB  
Article
Can Moringa Leaf Spray Treatment Increase the Nutraceutical Properties of Radish Baby Leaf?
by Daniela Romano, Giovanni La Fornara, Alessandro Tribulato and Stefania Toscano
Horticulturae 2022, 8(8), 671; https://doi.org/10.3390/horticulturae8080671 - 22 Jul 2022
Cited by 5 | Viewed by 2234
Abstract
Among the ready-to-use products, baby leaf salads (both raw and cooked), especially those belonging to the Brassicaceae family, represent a very interesting food typology, with nutraceutical properties. Recently, to obtain products with lower levels of synthetic chemicals and to improve nutritional quality, attention [...] Read more.
Among the ready-to-use products, baby leaf salads (both raw and cooked), especially those belonging to the Brassicaceae family, represent a very interesting food typology, with nutraceutical properties. Recently, to obtain products with lower levels of synthetic chemicals and to improve nutritional quality, attention has been paid to the use of natural biostimulants such as Moringa oleifera Lam. In this study, the aim was to investigate the effect of applying this natural biostimulant, at 15, 30, and 45 days from sowing, by spraying seedlings of radish (Raphanus sativus L.) each morning with Moringa oleifera leaf extract (MLE) at doses of 1:40 and 1:30 L−1 until dripping. Different morphological, physiological, and chemical parameters were determined. At harvesting time, the fresh biomass, total leaf area, and unit leaf area showed progressive increases as the dose of MLE was increased, while there were no significant difference in the dry biomass among the treatments. The quantum yield of PSII showed a significant increase in response to MLE treatments. The contents of chlorophylls and carotenoids were higher in both MLE treatments as compared with those of the control plants. The antioxidant capacity (DPPH) was not influenced by MLE treatment, while the influence was significant for total phenolic content (TPC). No significant differences were observed for the total sugar content, while the highest concentration of ascorbic acid was found with both MLE treatments; the MLE treatments did not modify the nitrate content. Therefore, MLE treatment showed a positive influence, although further studies are necessary to individuate the better doses and treatment modalities to improve the characteristics of radish baby leaf. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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11 pages, 680 KiB  
Article
Biostimulatory Response of Easily Extractable Glomalin-Related Soil Protein on Soil Fertility Mediated Changes in Fruit Quality of Citrus
by Xiao-Qing Liu, Ya-Chao Xie, Yan Li, Li Zheng, Anoop Kumar Srivastava, Abeer Hashem, Elsayed Fathi Abd_Allah, Wiwiek Harsonowati and Qiang-Sheng Wu
Agriculture 2022, 12(8), 1076; https://doi.org/10.3390/agriculture12081076 - 22 Jul 2022
Cited by 2 | Viewed by 1726
Abstract
Arbuscular mycorrhizal fungi secrete glomalin deposited into the soil as glomalin-related soil protein (GRSP), which possess multiple utility to benefit both soil as well as plant health. The present study aimed to assess the effects of the foliar application of an easily extractable [...] Read more.
Arbuscular mycorrhizal fungi secrete glomalin deposited into the soil as glomalin-related soil protein (GRSP), which possess multiple utility to benefit both soil as well as plant health. The present study aimed to assess the effects of the foliar application of an easily extractable GRSP (EE-GRSP) on the fruit quality, soil nutrients, and soil structural changes in three important citrus varieties (Satsuma mandarin Oita 4, Newhall navel orange, and Cocktail grapefruit). The exogenous EE-GRSP significantly elevated root mycorrhizal fungal colonization and soil hyphal length in Newhall and Oita 4 varieties, but without any such response in Cocktail grapefruit variety. The foliar spray of the EE-GRSP improved different external (e.g., pericarp, sarcocarp, and single fruit weight) and internal (e.g., soluble solids, titratable acids, and sugar contents) qualities of fruits to varying magnitudes, depending on citrus variety, with a more prominent effect on Cocktail grapefruit. EE-GRSP-treated fruits of Newhall and Oita 4 were more suitable for processing than non-treated control because of a low fruit hardness. However, no significant effect of the EE-GRSP was observed on the internal quality parameters of Newhall. EE-GRSP-treated citrus trees represented higher soil available nutrients over control, to some extent, especially on Oita 4. The foliar application of the EE-GRSP also increased various GRSP fractions to varying proportions and improved the distribution of water-stable aggregates in the size fraction of 0.25–2 mm, thereby increasing the mean weight diameter, particularly in Newhall and Cocktail grapefruit varieties. These observations provided clues about the stimulatory role of the EE-GRSP through soil structure and nutrient pool-mediated improvements in fruit quality. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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15 pages, 2460 KiB  
Article
The Impact of Aqueous Extracts of Verbesina sphaerocephala and Verbesina fastigiata on Germination and Growth in Solanum lycopersicum and Cucumis sativus Seedlings
by Ana Paulina Velasco-Ramírez, Alejandro Velasco-Ramírez, Rosalba Mireya Hernández-Herrera, Jesus Ceja-Esquivez, Sandra Fabiola Velasco-Ramírez, Ana Cristina Ramírez-Anguiano and Martha Isabel Torres-Morán
Horticulturae 2022, 8(7), 652; https://doi.org/10.3390/horticulturae8070652 - 18 Jul 2022
Viewed by 2185
Abstract
The use of extracts derived from different plants has gained popularity as an alternative option to manage weeds and support phenological development in plants. One of the main problems facing agricultural production is the intensive application of chemical fertilizers that harm the environment. [...] Read more.
The use of extracts derived from different plants has gained popularity as an alternative option to manage weeds and support phenological development in plants. One of the main problems facing agricultural production is the intensive application of chemical fertilizers that harm the environment. This study investigated the biostimulant effects of the aqueous extracts of Verbesinasphaerocephala and Verbesinafastigiata on the germination and growth of tomato (Solanum lycopersicum) and American cucumber (Cucumis sativus) seedlings. The aqueous extracts of both species of Verbesina were tested at concentrations of 0.5 and 1%. Seed germination and seedling development under nursery conditions were evaluated. The seed germination percentage was reduced in all treatments with the extracts of both Verbesina species when compared to that of the control treatment, which was considered an allelopathic effect. However, seedling growth in pots showed different behavior, with the extracts beneficially affecting certain agronomic variables, such as root and leaf length. The results suggest potential uses for V. sphaerocephala and V. fastigiata extracts, although a greater range of action may be experienced through the effects of certain molecules on weed growth. Additional studies with chemical approaches are necessary to better direct the uses and applications of Verbesina biomolecules, as they also functioned as growth promoters. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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18 pages, 1103 KiB  
Article
Analysis of RAZORMIN® as a Biostimulant and Its Effect on the Phytotoxicity Mitigation Caused by Fungicide Azoxystrobin in Pepper
by Ali Ahmad, Eloy Navarro-León, María José Izquierdo-Ramos, Juan José Rios, Begoña Blasco, Iván Navarro-Morillo and Juan Manuel Ruiz
Agronomy 2022, 12(6), 1418; https://doi.org/10.3390/agronomy12061418 - 13 Jun 2022
Cited by 3 | Viewed by 2486
Abstract
Use of biostimulants for stimulating plant growth and mitigating the negative impacts of biotic and abiotic stresses is a promising strategy to achieve higher crop yields. Fungicides such as azoxystrobin are used to control several pests and fungal diseases in plants but at [...] Read more.
Use of biostimulants for stimulating plant growth and mitigating the negative impacts of biotic and abiotic stresses is a promising strategy to achieve higher crop yields. Fungicides such as azoxystrobin are used to control several pests and fungal diseases in plants but at the cost of altering various physiological processes; thereby, leading to reduced crop yields. The efficiency of the compound RAZORMIN® as a biostimulant product while taking into account its role in plant growth stimulation and fungicide azoxystrobin stress mitigation was evaluated in this study. The efficacy of RAZORMIN® was assessed considering its impact on the stimulation of growth-related physiological processes and stress mitigation mechanism, e.g., reactive oxygen species (ROS) detoxification. Application of RAZORMIN® significantly increased plant growth by improving fresh weight, photosynthetic efficiency, net photosynthesis rate, gas exchange, nitrogen (N) metabolism (with increases in soluble amino acids, foliar N concentration, and N use efficiency), growth hormone concentrations (mainly gibberellins and cytokinins), nutritional status of plants (producing a greater accumulation of phosphorus, potassium, calcium, magnesium, sulfur, zinc, molybdenum, iron, and boron), and sugars concentration. Furthermore, the application of RAZORMIN® on plants under fungicide azoxystrobin stress demonstrated its anti-stress and protective role by stimulating the antioxidant defense system and improving photosynthetic efficiency. Full article
(This article belongs to the Topic Biostimulants in Agriculture)
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