Microbiota asociada al cultivo de banano en Costa Rica y otras regiones: conceptos e implicaciones en el manejo del cultivo

Suppressing soil-borne diseases with residue management and organic amendments

Organic amendments: microbial communities and their role in plant fitness and disease suppression Organic amendments have long been used to improve soil fertility, structure, and water-holding capacity, thereby promoting plant growth and productivity (Bailey and Lazarovits, 2003; Larney and Angers, 2012; Meghvansi and Varma, 2015). In addition to their physical and chemical benefits, organic amendments also play a critical role in shaping the soil microbial communities, which are key drivers of plant fitness and health (Pascale et al., 2020) . Recent advances in high-throughput sequencing and omics technologies have shed new light on the complex interactions between organic amendments, microbial communities, and plants. Understanding the mechanisms by which organic amendments impact soil microbial communities and plant health is critical for developing sustainable agricultural practices. In this Research Topic, we gathered the latest research on the effects of organic amendments on soil microbial communities, nutrient cycling, plant growth promotion, and disease suppression. The seven research articles in this Research Topic cover a wide range of topics, including the impact of various organic amendments on soil microbes and their functions and the mechanisms underlying these interactions. One of the main themes of this Research Topic is the use of organic amendments to enhance soil microbial diversity and activity, which in turn can improve plant growth and health. Zhang M. et al. investigated the effect of biochar on soil nutrient content, enzymatic activity, and fungal community structure in yellow soil typical of karst areas. Three biochar levels (0%, 1.0%, and 4.0%) showed that biochar increased pH, organic matter, total nitrogen, available phosphorus, and potassium, but decreased microbial biomass. High-applicationrate biochar increased the abundance of certain fungal genera while impeding harmful pathogen growth and increasing the abundance of beneficial fungi. Biochar positively Frontiers in Plant Science frontiersin.org 01

Soil sickness represents a condition in which the long-term use of non-sustainable agricultural practices causes changes in the physical, chemical and biological properties of soils that, in turn, negatively affects plant vegetative and reproductive performances. By an extensive analysis of literature, we found that soil sickness is pervasive in agro-ecosystems, occurring in 111 cultivated plants belonging to 41 taxonomic families. To explain the phenomenon of soil sickness, three main hypotheses have been proposed, including soil nutrient depletion or imbalance, build-up of soilborne pathogens coupled with shift in the composition of soil microbial community composition, and presence of phytotoxic and autotoxic compounds. Starting from a detailed analysis of mechanisms it was previously suggested that all proposed hypotheses have as common origin, i.e. the alteration of organic matter cycle caused by intensive agricultural practices. Based on this consideration, in the present thesis different organic management strategies, in terms of organic matter type and application frequency, were used in order to recover a soil affected by soil sickness. Soil was subjected for two years to 11 different treatments including two ordinary soil managements, eight organic amendment treatments and one untreated soil as the control. At the end of each year, cumulated crop production of Eruca sativa, soil properties and soil microbiota were evaluated. Compared to the use of ordinary managements, the beneficial effects on soil properties and microbial community derived by the use of organic amendments were evident already after one year of conditioning. In detail, pH values near the neutrality, high soil organic carbon content and good level of soil aggregation, as well as an improvement in soil microbial functionality, richness and diversity were observed in soil treated with organic amendments, especially when easily decomposable materials rich in labile carbon and organic nitrogen (i.e., alfalfa plus glucose) were applied at high rate once a year. In contrast, cumulated crop production at the end of the first year was higher in soil with ordinary managements than in soil with application of organic materials. However, during the second year of soil conditioning, an increase in productivity and quality of the crop was observed in soil treated with organic materials as compared to the soil subjected to conventional management. Finally, soil conditioned for two years was used to evaluate the effects that ordinary and organic management strategies had in the disease suppression of soilborne phytopathogenic fungi and viruses. Application of organic amendments, by positively affecting soil properties and soil microbiota, showed a restoration of natural soil suppressivines against soilborne pathogens (i.e., Sclerotinia sclerotiorum and Fusarium oxysporum f. sp. raphani). Surprisingly, this study reports for the first time that the use of organic matter reduces the incidence of Tomato spotted wilt virus infection, as well as the mortality of infected plants, probably by the induction of systematic resistance. In conclusion, this study revealed that applications of organic materials have an immediate positive effect on soil fertility as well as on soil microbiota, while the increase of crop productivity are of longer-term nature. In addition, the positive effect that organic amendments have on microbial communities, including their abundance, diversity and richness of the several taxa, results in a recovery of the natural soil suppression against soilborne pathogens and the induction of plant resistance against airborne pathogens like viruses. However, the effects on crop production, soil fertility and disease suppression varied depending on quality, amount and frequency of application of organic matter. Therefore, future studies that include different combinations of organic amendment types and application frequencies, as well as different soil types, crop species and pathosystems, are needed to better understand the role of organic matter as a means to recover of soils affected by soil sickness.

A Field trial was conducted at the Eastern farm of Michael Okpara University of Agriculture, Umudike, during the 2012 farming season to assess the potentials of some organic soil amendments and some botanicals as foliar sprays in the control of some common bacterial diseases associated with munbean (Vigna radiata L.) which include bacterial blight, halo blight, leaf spot and bacterial wilt. The soil organic amendments employed as control measure included leaves of Azadirachta indica, Delonix regia, poultry droppings and kitchen ash while the plant extracts that served as foliar sprays in control of these bacterial diseases were: neem seed (A. indica), ginger stem (Zingiber officinale) and bitter kola seed (Garcinia kola), water was used as a control while streptomycin sulphate served as a standard check. A. indica and D. regia leaves were first allowed to decompose before application as organic amendments. All the experiment was in a randomized complete block design (RCBD) and replicated three times. Results obtained showed that organic amendments sourced from kitchen ash improved growth of mungbean, sustained total pod yield and suppressed disease incidence and severity. Foliar spray trials results showed that A. indica was the best in enhancing growth, yield (seed weight) and most effective in reducing disease incidence and disease severity more than other plant extracts.

This review aims to contribute to a holistic understanding of sustainable crop production strategies in the face of climate variability, offering insights for researchers, policymakers, and practitioners working at the intersection of agriculture and climate resilience. Climate change poses a significant threat to global agricultural productivity, directly impacting food security, farmer livelihoods, and the sustainability of cropping systems. Increasing temperatures, erratic rainfall patterns, extended droughts, and frequent extreme weather events are disrupting conventional agricultural practices, particularly in vulnerable regions. In this context, climate-resilient agronomic practices have emerged as crucial adaptive strategies to sustain and enhance crop production under changing environmental conditions. This review highlights recent advances and innovative approaches in climate-resilient agronomy, emphasizing sustainable practices that optimize resource use efficiency, conserve soil and water, and improve crop tolerance to climatic stresses. The use of crop varieties that are resistant to heat and drought, conservation agriculture methods, integrated nutrient and water management, precision farming, crop diversification, and agroforestry systems are some of the important practices that are covered. Agronomic practices treated in this review, such as the application of stress-tolerant crop varieties, conservation agriculture practices, integrated nutrient and water management, precision farming, and agroforestry, have been proven effective in various agro-ecological environments. Furthermore, the study also discussed how organic amendments, biofertilizers, and climate-wise smart soil management strategies might improve soil health and carbon sequestration. To further on-farm risk management and decision-making, the paper also examines the integration of digital agriculture tools including remote sensing, weather forecasting, and decision support systems. This review emphasizes the need for a systems-based agronomic approach that fits production goals with environmental sustainability by combining recent research findings and successful field-level interventions. The results support increasing policy support, farmer capacity-building, and technology distribution to encourage broad application of climate-resilient agronomic practices. Food and nutritional security, improved farm incomes, and resilience in agricultural systems against the negative effects of climate change depend on such efforts.

Manure-derived organic amendments are a cost-effective tool that provide many potential benefits to plant and soil health including fertility, water retention, and disease suppression. A greenhouse experiment was conducted to evaluate how dairy manure compost (DMC), dairy manure compost-derived vermicompost (VC), and dehydrated poultry manure pellets (PP) impact the tripartite relationship among plant growth, soil physiochemical properties, and microbial community composition. Of tomato plants with manure-derived fertilizers amendments, only VC led to vigorous growth through the duration of the experiment, whereas DMC had mixed impacts on plant growth and PP was detrimental. Organic amendments increased soil porosity and soil water holding capacity, but delayed plant maturation and decreased plant biomass. Composition of bacterial communities were affected more by organic amendment than fungal communities in all microhabitats. Composition of communities outside roots (bulk soil, rhizosphere, rhizoplane) contrasted those within roots (endosphere). Distinct microbial communities were detected for each treatment, with an abundance of Massilia, Chryseolinea, Scedosporium, and Acinetobacter distinguishing the control, vermicompost, dairy manure compost, and dehydrated poultry manure pellet treatments, respectively. This study suggests that plant growth is affected by the application of organic amendments not only because of the soil microbial communities introduced, but also due to a synergistic effect on the physical soil environment. Furthermore, there is a strong interaction between root growth and the spatial heterogeneity of soil and root-associated microbial communities.

Identifying the characteristics of organic soil amendments that suppress soilborne plant diseases

Both soil and the human gut support vast microbial biodiversity, in which the microbiota plays critical roles in regulating harmful organisms. However, the functional link between microbiota taxonomic compositions and disease suppression has not been explained yet. Here, we provide an overview of pathogen regulation in soil and mammals gut, highlighting the differences and the similarities between the two systems. First, we provide a review of the ecological mechanisms underlying the regulation of soil and pathogens, as well as the link between disease suppression and soil health. Particular emphasis is thus given to clarifying how soil and the gut microbiota are associated with organic amendment and the human diet, respectively. Moreover, we provide several insights into the importance of organic amendment and diet composition in shaping beneficial microbiota as an efficient way to support crop productivity and human health. This review also discusses novel ways to functionally characterize organic amendments and the proper operational combining of such materials with beneficial microbes for stirring suppressive microbiota against pathogens. Furthermore, specific examples are given to describe how agricultural management practices, including the use of antibiotics and fumigants, hinder disease suppression by disrupting microbiota structure, and the potentiality of entire microbiome transplant. We conclude by discussing general strategies to promote soil microbiota biodiversity, the connection with plant yield and health, and their possible integration through a “One Health” framework.

The sub‐mountainous tea gardens of the Dooars region of West Bengal, which contribute approximately 25% of the national tea yield, are constantly fighting with diminishing soil fertility. Inorganic alternatives like chemical fertilizers can provide easier yet short‐term solutions, as their prolonged and indiscriminate usage leaches the soil, devouring its productivity, increasing the soil's heavy metal contents, and subsequently accumulating those heavy metals in leaves. A plausible substitution in this scenario could be the use of organic alternatives like composting or biofertilizer. Although references to such alternative means are found in the literature, a holistic approach targeting plant growth promotion along with mitigating soil metal toxicity is lacking. Keeping this background in mind, this pilot study was designed to optimize the dosage of novel biofertilizers (using resident and alien flora) that can reduce heavy metal loads and residual toxicity in soil, thereby improving overall soil health and tea production. Two potential metallophilic plant growth‐promoting strains of Bacillus sp. (previously reported) were selected and applied to potted tea plants of two different varieties of tea: TV9 and TV25. Among the two modes of treatment tested: solid treatment (compost amended with bacterial culture) and liquid treatment (cell pellets mixed in water suspension), the water suspension‐based direct application of resident soil bacteria showed the highest physiological growth with reduced metal toxicity. Based on physiological data and physico‐chemical data collected, it was observed that direct application of bacteria showed better results in both plant and soil health improvement in comparison to regular compost amended with beneficial microflora. Therefore, this small‐scale pilot study aimed to optimize the dosage and mode of application of novel biofertilizers for improved soil and plant health.

The application of organic amendments (OAs) obtained from biological treatment technologies is a common agricultural practice to increase soil functionality and fertility. OAs and their respective pretreatment processes have been extensively studied. However, comparing the properties of OAs obtained from different pretreatment processes remains challenging. In most cases, the organic residues used to produce OAs exhibit intrinsic variability and differ in origin and composition. In addition, few studies have focused on comparing OAs from different pretreatment processes in the soil microbiome, and the extent to which OAs affect the soil microbial community remains unclear. This limits the design and implementation of effective pretreatments aimed at reusing organic residues and facilitating sustainable agricultural practices. In this study, we used the same model residues to produce OAs to enable meaningful comparisons among compost, digestate, and ferment. These three OAs contained different microbial communities. Compost had higher bacterial but lower fungal alpha diversity than ferment and digestate. Compost-associated microbes were more prevalent in the soil than ferment- and digestate-associated microbes. More than 80% of the bacterial ASVs and fungal OTUs from the compost were detected 3 months after incorporation into the soil. However, the addition of compost had less influence on the resulting soil microbial biomass and community composition than the addition of ferment or digestate. Specific native soil microbes, members from Chloroflexi, Acidobacteria, and Mortierellomycota, were absent after ferment and digestate application. The addition of OAs increased the soil pH, particularly in the compost-amended soil, whereas the addition of digestate enhanced the concentrations of dissolved organic carbon (DOC) and available nutrients (such as ammonium and potassium). These physicochemical variables were key factors that influenced soil microbial communities. This study furthers our understanding of the effective recycling of organic resources for the development of sustainable soils.

Co-application of biochar with other amendments is generating interest as a means to increase biochar effectiveness for improving soil health. Yet, the extent to which such co-application improves soil health is unclear. This paper (i) synthesized the impact of biochar applied with or without organic and inorganic amendments on soil health indicators including soil physical, chemical, and biological properties using field studies, (ii) discussed potential factors that may affect the performance of the co-application, and (iii) summarized research needs. Based on 28 peer-reviewed publications up to September 30, 2024, biochar co-application improved 9 of 16 soil properties compared to biochar alone. It enhanced wet aggregate stability in 5 of 9 comparisons by 45%, saturated hydraulic conductivity in 5 of 6 by 17%, field water content in 8 of 14 by 20%, cation exchange capacity in 9 of 17 by 58%, and organic matter concentration in 5 of 9 by 37%. Also, co-application of biochar increased soil microbial biomass C, phosphatase activity, and N and P concentrations by 33% to 76% in most comparisons. However, it had mixed effects on bulk density, pH, electrical conductivity, C and K concentrations, as well as urease and dehydrogenase activities. Biochar co-application with organic amendments (compost/manure) improved soil physico-chemical properties (bulk density, C, N, P, K) more consistently than with inorganic amendments (NPK). The benefits of biochar co-application increased with higher application rates. These findings suggest that biochar co-application can improve selected soil properties more than biochar alone, with benefits for soil structure, water retention, nutrient availability, and microbial activity, though results for some properties remain inconsistent. Long-term studies (>5 years) across diverse soils and climates are needed to further elucidate these effects and optimize biochar co-application strategies for sustainable soil management. Highlights Biochar co-applied with amendments (compost/manure/NPK) improves some soil properties over biochar alone Soil benefits increase with an increase in biochar co-application rate Biochar + organic amendments are more effective than biochar + inorganic amendments Graphical Abstract

Agriculture is faced with many challenges including loss of biodiversity, chemical contamination of soils, and plant pests and diseases, all of which can directly compromise plant productivity and health. In addition, inadequate agricultural practices which characterize conventional farming play a contributory role in the disruption of the plant-microbe and soil-plant interactions. This review discusses the role of organic amendments in the restoration of soil health and plant disease management. While the use of organic amendments in agriculture is not new, there is a lack of knowledge regarding its safe and proper deployment. Hence, a biorational approach of organic amendment use to achieve sustainable agricultural practices entails the deployment of botanicals, microbial pesticides, and organic minerals as organic amendments for attaining plant fitness and disease suppression. Here, the focus is on the rhizosphere microbial communities. The role of organic amendments in stimulating beneficial microbe quorum formation related to the host-plant-pathogen interactions, and its role in facilitating induced systemic resistance and systemic-acquired resistance against diseases was evaluated. Organic amendments serve as soil conditioners, and their mechanism of action needs to be further elaborated to ensure food safety.

Shocks and Bribri Agriculture Past and Present

A field experiment was conducted on sandy textured soil under sprinkler irrigation system during the two successive agricultural growing seasons of (2009/2010) and (2010) at Ismailia Agricultural Research Station, AgriculturalResearchCenter. Ismailia governorate, Egypt, to evaluate the effect of applying some organic soil amendments i.e.,compost at rates of (2.5, 5, and 7.5 tonfed-1), humic acid rate of (5l fed-1) and biofertilizer (Bacillus Polymxa) individually or incorporated with biofertilizer on the fertility status, some soil physico -chemical properties, and productivity of wheat plants (Triticumvulgare) C.V. Giza 168 and peanut plants (Arachishypogaeal.) C.V. Giza 4. The experiment was designed statistically as a split plots with three replicates. The main plots were located for the biofetilization and the sub plots were devoted for the organic amendments types. At the end of the growing seasons (i.e. after 6 and 4 months from plantation of wheat and peanut respectively) some hydro physical and chemical properties of the soil were determined The obtained results revealed that application of either organic amendments or bio fertilizer as individual or in combination improved fertility status of the soil as well as, the seed yields of wheat and peanut. These include, (a) Increasing available N, P, and K of the treated soil. (b) Increasing OM content in treated soil. Mixing soil conditioners together i.e. organic amendments and biofertilizer was more efficient in improving chemical properties of the soil than applying each of them alone. In this context, the maximum content of available NPK were (22.64, 13.23 and 68.41 mg kg-1 soil) and (24.14, 13.71 and 70.46 mg kg-1 soil) for N, P and K in the soil after wheat and peanut harvesting, respectively, resulted from the high rate of compost (7.5 ton fed-1) combined with biofertilizers. (c) Increases in the concentration of (N, P, and K) in the seeds as well as yields of seed. It's also noticed that yields significantly increased by increasing rate of organic fertilizer, which amounted to 1.50 times for wheat seed vs 1.95 times for peanut seed over control treatment by treating the soil with compost at rate of ( 7.5 tonfed-1), in sequence. Applied conditioners significantly improved the hydro physical properties of the soil. These include, (a) decreasing soil bulk density as well as macro porosity (drainage pores) on the expense of micro ones. Therefore, water holding pores were increased, (b) increasing retained moisture in the soil at field capacity, wilting point and available water because the increase in water retained in the soil at field capacity is far beyond that at wilting percentage, available water was highly increased. (c) Decreasing soil hydraulic conductivity. Generally, mixing both types of soil conditioners together i.e. organic amendments and biofertilizer was more efficient in improving physico- chemical properties of the soil than applying each of them alone.

Agricultural practices and sustainable livelihoods: Rural transformation within the Loess Plateau, China