Cláudio Roberto Fonsêca Sousa Soares

Arbuscular mycorrhizal fungi (AMF) establish symbioses with most terrestrial plants, enhancing nutrient uptake, stress tolerance, and soil quality. We evaluated the use of Rhizophagus irregularis -based inoculants in cover crops and subsequent commercial crops in a no-till system and assessed their effects on soil biological attributes and crop yield. Three on-farm field experiments in different locations were conducted with common bean, okra, and corn cultivated after the winter cover crops. The assays were arranged in a randomized complete block design with a split-plot scheme and four replicates, with cover crop inoculation (black oats) as the main factor and crop inoculation in the subplot. The treatments included (i) inoculation in the cover crop and no inoculation in the main crop; (ii) no inoculation in the cover crop and inoculation in the main crop; (iii) inoculation in both crops; and (iv) no inoculation in either crop. Soil acid phosphatase activity, fluorescein diacetate hydrolysis, AMF spore density, and crop yield were measured at the end of each cycle, and the AMF community composition was characterized. The AMF inoculant increased the soil quality indicators (acid phosphatase activity and fluorescein diacetate hydrolysis). Inoculation of the cover crops did not replace the beneficial effects of direct inoculation on the yields of beans, okra, or corn. The results of the experiments in locations with different soils revealed that, overall, direct crop inoculation increased the yields of bean, okra, and corn by 30%, 33%, and 19%, respectively, and intensified soil enzyme activity, with no detectable effects on soil AMF community diversity or structure.

Mycorrhizal inoculants can contribute to the development of corn crops by improving crop productivity. In this sense, the objective of this study was to evaluate the effects of a mycorrhizal inoculant on the dynamics of root system growth, gas exchange, corn crop productivity, and microbial activity in the rhizospheric soil in a no-till area with different levels of available soil phosphorus. The experiment was conducted during the 2019/2020 and 2020/2021 growing seasons. At 75 days after plant emergence, root morphological parameters (total root length (cm), average root diameter (mm), root surface area (cm²), and root volume), shoot biomass production, P content in the plant shoots, gas exchange, and microbiological attributes of the rhizospheric soil of corn were evaluated. At the end of the cycle, corn grain yield was determined. A beneficial effect of AMF inoculation was observed on the root and shoot parameters regardless of soil P level. Under conditions of evenly distributed rainfall during the experiment (2019/2020 season), AMF inoculation contributed to a 90% increase in acid phosphatase activity and a 76% increase in microbial biomass carbon (C-BIO), independent of soil P level. In contrast, under water deficit conditions (2020/2021 season), AMF inoculation provided a 29% increase in grain yield. We concluded that introducing a commercial mycorrhizal inoculant in corn benefits root system morphological parameters and physiological traits, and favors the activity of enzymes related to increased P availability, contributing to increased crop productivity in a no-till system.

We assessed, in a field experiment, the effects of arbuscular mycorrhizal fungi (Rhizophagus intraradices) and plant growth-promoting bacteria (Azospirillum brasilense) on the soil biological activity and the growth of key pioneer species used in the revegetation of coal-mining areas undergoing recovery. We applied four inoculation treatments to the pioneer plant species (Lablab purpureus, Paspalum notatum, Crotalaria juncea, Neonotonia wightii, Stylosanthes guianensis, Andropogon gayanus and Trifolium repens) used in the recovery process: NI (Control – Non-inoculated), AZO (A. brasilense), AMF (R. intraradices), and co-inoculation of AZO and AMF. On the 75th and 180th days, we measured plant dry mass, mycorrhizal colonization, N and P concentration, and accumulation in plant tissue. We collected soil to quantify glomalin content and soil enzyme activity. After 180 days, we did a phytosociological characterization of the remaining spontaneous plants.The both microorganisms, singly or co-inoculated, promoted increases in different fractions of soil glomalin, acid phosphatase activity, and fluorescein diacetate activity at 75 and 180 days. The inoculation was linked to higher plant biomass production (62-89%) and increased plant P and N accumulation by 34-75% and 70-85% at 180 days, compared with the non-inoculated treatment. Among the pioneer species sown Crotalaria juncea produced the highest biomass at the 75th and 180th days (67% and 76% of all biomass), followed by Lablab purpureus (3% and 0.5%), while the other species failed to establish. At 180 days, we observed twenty spontaneous plant species growing in the area, primarily from the Poaceae family (74%). That suggests that the pioneer species present in the area do not hinder the ecological succession process. Inoculation of R. intraradices and A. brasilense, isolated or combined, increases soil biological activity, growth, and nutrient accumulation in key pioneer plant species, indicating the potential of that technique for the recovery of lands degraded by coal mining.

In recent years, the research that look for biological technologies that guarantee sustainable agricultural production and application methods that maximize the benefits of adopting this practice has been increasing. This study aimed to assess, for the first time, the different application methods and agronomic efficiency of Azospirillum brasilense Az39 for corn cultivation in Brazil. Four trials were conducted under different soil and climate conditions in the 2017 - 2018 harvests (Santa Maria-RS and Ibirubá-RS, Brazil) and 2019 harvest (Londrina-PR and Primavera do Leste-MT, Brazil). The experimental design used was a randomized block, evaluating three inoculation treatments with 10 replicates each: control = non-inoculated ; TS = inoculation with A. brasilense Az39 via corn seed; and Foliar500 = foliar application of A. brasilense Az39 at the V4 stage of corn. The A. brasilense Az39 strain was effective in Brazilian soils and increased corn grain yield in all evaluated areas. Furthermore, foliar application of this strain at a dosage of 500 mL ha-1 resulted in greater increases compared to seed treatment. Thus, the A. brasilense Az39 strain is a promising bio-input technology for Brazilian agriculture. Nos últimos anos tem sido crescente a busca por tecnologias biológicas que garantam uma produção agrícola sustentável e métodos de aplicação que maximizem os benefícios da adoção desta prática. O presente estudo teve como objetivo avaliar de forma inédita diferentes métodos de aplicação e a eficiência agronômica de Azospirillum brasilense Az39 para a cultura do milho no Brasil. Para tanto, ensaios foram conduzidos em condições edafoclimáticas distintas nas safras 2017 - 2018 (Santa Maria-RS e Ibirubá-RS, Brasil) e safra 2019 (Londrina-PR e Primavera do Leste-MT, Brasil). O delineamento experimental utilizado foi em blocos casualizados, avaliando-se três tratamentos de inoculação com 10 repetições, sendo estes: Controle = não inoculado; TS = inoculação de A. brasilense Az39 via semente de milho; Foliar500 = aplicação foliar de A. brasilense Az39 no estádio V4 do milho. Foi verificado que a estirpe A. brasilense Az39 foi eficiente em solos brasileiros, proporcionando aumentos na produtividade do milho em todas as áreas avaliadas. A aplicação foliar desta estirpe na dosagem de 500 mL ha-1 proporcionou incrementos superiores aos obtidos com o tratamento de sementes. Desta forma, a estirpe A. brasilense Az39 demonstrou ser uma tecnologia de bioinsumo promissora para a agricultura brasileira.

The use of plant-based and micro-organism-based biological inputs is a sustainable agricultural practice. It promotes a suitable and better utilization of non-renewable resources in the environment. The benefits of using micro-organisms are associated with direct and indirect mechanisms, mainly related to improvements in the absorption and availability of nutrients, resulting in a consequent impact on plant growth. The main benefits of using biochemical pesticides are the promotion of sustainability and the management of resistance to pests and diseases. Although the use of micro-organisms and botanical metabolites is a promising agricultural alternative, they are still primarily concentrated in grain crops. There is a huge opportunity to expand the plant-based and micro-organism-based biological inputs used in agriculture due to the wide range of mechanisms of action of those products. At a global level, several terminologies have been adopted to characterize biological inputs, but many terms used conflict with Brazilian legislation. This review will clarify the classes of biological inputs existing in Brazil as well as present the application and evolution of the market for microbiological and plant-based inputs.

The use of plant-based and microorganism-based biological inputs is a sustainable agricultural practice, promoting a suitable and better utilization of non-renewable resources in the environment. The benefits of using microorganisms are associated with both direct and indirect mechanisms, primarily related to improvements in nutrient absorption and availability, as well as plant growth. The main benefits of using biochemical pesticides are the promotion of sustainability and the management of resistance. Although the use of microorganisms and botanical metabolites is a promising agricultural alternative, it is still primarily concentrated in grain crops. However, due to the wide range of mechanisms of action of plant-based and microorganism-based biological inputs, there is an opportunity to expand their use in agriculture. In the Brazilian biological inputs market, various terminologies have been used to characterize biological-based products, with many of these terms being employed incorrectly and sometimes conflicting with the country’s legislation. Therefore, this review presents the classes of biological inputs and the application and evolution of the plant-based and microbiological-based product market in different crops in Brazil.

A atividade suinícola vem apresentando-se como altamente poluidora devido ao volume de dejetos gerado, usualmente aplicados em áreas agricultáveis e que podem contaminar o solo e mananciais hídrico, especialmente com o fósforo (P). Nesse contexto, o objetivo do presente estudo é avaliar a contaminação da água e do solo por fósforo, influenciado pela atividade suinícola, na bacia hidrográfica Rio Coruja/Bonito, em Braço do Norte/SC. O presente estudo foi desenvolvido em quatro propriedades suinícolas e no Rio Coruja, no período de Julho/2015 a Junho/2016. Foram coletadas amostras de água (Jul/2015, Out/2015, Dez/2015, Mar/2016 e Jun/2016) e de solo (Dez/2015). Nas amostras de água foram determinados os teores de P dissolvido (Pd), P particulado (Pp), P total (Pt) e Índice de Estado Trófico (IET), aplicando-se os valores limítrofes conforme a Resolução CONAMA nº357/2005. Nas amostras de solo foram determinados os teores de P extraído por Mehlich-1 e de argila, a partir dos quais foi calculado o Limite Crítico Ambiental de Fósforo (LCA-P). Os teores de Pt na água apresentaram-se acima do limite estabelecido pela legislação vigente, com potencial para causar a eutrofização e reduzir a qualidade da água em todos os pontos avaliados. Associado a isso, a aplicação de dejetos suínos no solo em áreas agricultáveis contribui com aporte de material particulado, bem como o solo como fonte de P aos corpos hídricos. Dessa forma, em áreas que recebem aplicações de dejetos de suínos, recomenda-se o uso de medidas mitigatórias que reduzam as transferências de água e sedimentos para os mananciais hídricos, como a adoção de sistemas conservacionistas de manejo do solo, reduzindo, também, o transporte de P e outros elementos potencialmente contaminantes.

This research identified arbuscular mycorrhizal fungi (AMF) in rhizosphere soil of grapevines with Grapevine Death and Decline symptoms (GDD) or asymptomatic healthy (H) plants, and characterized the relationship of AMF communities with soil chemical attributes. The AMF spore number ranged from 287 to 432 spores 50 cm-3 in soil with GDD plants, and from 357 to 464 spores 50 cm-3 in H plants, with no differences among vineyards or between GDD and H plants within each vineyard. We detected 42 species and 17 genera, and most taxa belonged to Acaulosporaceae or Glomeraceae. Claroideoglomus etunicatum, Funneliformis mosseae, and Archaeospora trappei were the most frequent species in all vineyards. Soil chemical attributes were not determinant for the occurrence of most fungal species; although, Entrophospora infrequens, Diversispora sp1 and Diversispora sp2 were associated with a vineyard having high soil copper. Vineyards harbor highly diverse AMF communities, which are determined by location.