Combined effect of Pseudomonas sp. and Trichoderma aureoviride on lettuce growth promotion

Plant growth promotion by microorganisms may be a viable alternative to increase lettuce production through pathogens control and nutrients absorption increase. Trichoderma and Pseudomonas genus are examples of widely studied microorganisms with the capacity to promote plant growth. However, there are still gaps regarding the action of the combined effect of these two microorganisms. Therefore, the objective of this study was to evaluate the combined effect of Pseudomonas sp. UAGF14 and Trichoderma aureoviride URM5158 on the development of lettuce plants. The experimental design was completely randomized, with five treatments: CONT (control), CM (soil with organic fertilization), CMB (soil with organic fertilization and Pseudomonas sp.), CMF (soil with organic fertilization and T. aureoviride), and CMFB (soil with organic fertilization, Pseudomonas sp. and T. aureoviride), with ten repetitions. At 30, 40 and 60 days after sowing, the following parameters were analyzed: plant and canopy height and number of leaves. At 60 days after emergence, shoot dry matter, leaf area, root dry matter, root length and chlorophyll were analyzed. Catalase, peroxidase and polyphenol oxidase enzymatic activity were determined. The CMFB treatment had the highest means of lettuce growth promotion, confirming the synergistic effect of the combination of the two microorganism types, as it increased height, canopy, shoot and root dry matter, and chlorophyll levels compared to CONT, although did not differ from CM in some variables. Enzymatic activity was also influenced by the action of these microorganisms combined, evidencing by polyphenol oxidase increase. The CMFB or CM were efficient in promoting lettuce growth, showing positive response to the plant morphological and physiological characteristics. However, few responses were observed in lettuce plant growth in the first cycle evaluated after 60 days, compared CM and CMFB treatments, but both treatments showed superiority in lettuce plant growth submitted to CONT treatment. Therefore, further studies are needed to estimate the long-term effects of combined effect of Pseudomonas sp. UAGF14 and T. aureoviride URM5158 on crop productivity in field conditions

Isolation and characterization of plant growth promoting bacteria from the eucalyptus rhizosphere

O eucalipto necessita de adequada adubação para obtenção de melhor produtividade e qualidade da madeira. Em geral, os plantios de eucalipto são estabelecidos em solos de baixa fertilidade, onde as populações microbianas do solo podem contribuir significativamente para a disponibilização de nutrientes para as plantas. A associação com bactérias promotoras do crescimento de plantas (BPCP) pode contribuir para o crescimento e desenvolvimento do eucalipto por meio de mecanismos promotores do crescimento vegetal. O objetivo deste trabalho foi isolar BPCP da rizosfera de eucalipto, estudar a expressão dos mecanismos de promoção de crescimento in vitro e testar o efeito da inoculação bacteriana no crescimento de Eucalyptus grandis em condições de casa de vegetação. O isolamento das potenciais BPCP foi realizado em meios próprios para o isolamento de procariotos diazotróficos (LGI, JNFB, JMV, LGIP e NFB) usando amostras de solo rizosférico de eucalipto. Após o isolamento em cultura pura, 51 isolados foram caracterizados pela técnica de coloração de Gram e identificados pelo método MIDI. Os isolados capazes de solubilizar Ca 3 (PO 4 ) 2 e Al(PO 4 ) foram testados quanto à solubilização de fosfatos de rocha (FR) de Patos, Catalão, Araxá, Crandalita, Itafós Abaeté, Gafsa e Aipe. Todos os isolados foram testados quanto à capacidade de promoção de crescimento de E. grandis em casa de vegetação por 120 dias. Após o cultivo, foram avaliadas as seguintes variáveis: altura, número de folhas, matéria seca das raízes (MSR), matéria seca foliar (MSF), matéria seca do caule (MSC), matéria seca total (MST), bem com o conteúdo de N, P, K, Ca e Mg e a eficiência de uso de nutrientes (EUN). Os isolados obtidos pertencem aos gêneros Ralstonia, Bacillus, Stenotrophomonas, Paenebacillus, Staphylococcus, Virgibacillus, Burkholderia, Pseudomonas e Xanthomonas. Os valores de solubilização de fosfato de cálcio variaram de 24,84 a 178,48 mg L -1 . Para o fosfato de alumínio, os valores obtidos variaram de 7,68 a 29,68 mg L -1 . O isolado mais eficiente solubilizou 17,86% do P do fosfato tricálcico. Os isolados LEM 10 e LEM 36 apresentaram capacidades distintas de solubilizar os diferentes tipos de FR testados. A susceptilidade à solubilização microbiana decresceu na seguinte ordem: Gafsa > Araxá > Abaeté > Catalão > Aipe > Patos > Itafós > Crandalita. As porcentagens médias de P solubilizado variaram de 0,25%, para a Crandalita, a 25% para Gafsa. A inoculação com alguns isolados bacterianos promoveram ganhos máximos de MSR e MST de 1.137 e 695%, respectivamente, em relação ao tratamento controle não inoculado. A inoculação com os isolados de BPCP aumentou o conteúdo e a EUN de todos os macronutrientes avaliados. No caso do P e N, na MST, os conteúdos desses nutrientes apresentaram aumentos máximos decorrentes da inoculação bacteriana de 644 e 505%, respectivamente. Já para o cálcio, os ganhos máximos corresponderam a 572,8% na MST. As análises de agrupamento e componentes principais revelaram três grupos de BPCP, sendo o isolado de melhor desempenho o Bacillus cereus GC subgroup B (LEM 29). Além da atividade diazotrófica, as culturas obtidas apresentaram a capacidade de solubilizar fontes de fósforo pouco reativas, constituindo ferramenta com potencial de aplicação em viveiros florestais. Palavras-chave: Acidez titulável. Macronutrientes. Nutrição vegetal. pH. Solubilização de fosfato.Eucalyptus plants require adequate fertilization to achieve better productivity and wood quality. In general, eucalyptus plantations are established in soils with low fertility, where soil microbial populations can significantly contribute to nutrient availability to plants. The association with plant growth-promoting bacteria (PGPB) can contribute to the growth and development of eucalyptus through plant growth-promoting mechanisms. The objective of this work was to isolate PGPB from the eucalyptus rhizosphere, taxonomically characterize them, study the expression of its growth promotion mechanisms in vitro and to test their effect on the growth of Eucalyptus grandis under greenhouse conditions. The isolation of potential PGPB was carried out in media suitable for cultures of diazotrophic prokaryotes (LGI, JNFB, JMV, LGIP and NFB) using rhizospheric soil samples from E. grandis. After isolation in pure culture, 51 isolates were characterized by the Gram stain technique and identified by MIDI. Isolates capable of solubilizing Ca 3 (PO 4 ) 2 and Al(PO 4 ) were used for the solubilization of rock phosphates (RP): Patos, Catalão, Araxá, Crandalita, Itafós Abaeté, Gafsa, and Aipe. All isolates were tested as to their capacity to promote E. grandis growth in the greenhouse for 120 days. After cultivation, the following variables were evaluated: height, number of leaves, root dry matter content (RDMC), leaf dry matter content (LDMC), stem dry matter (SDM), total dry matter (TDM), as well as N, P, K, Ca, and Mg content and the nutrient use efficiency (NUE). The isolates obtained belong to the genera Ralstonia, Bacillus, Stenotrophomonas, Paenebacillus, Staphylococcus, Virgibacillus, Burkholderia, Pseudomonas and Xanthomonas. Calcium phosphate solubilization values ranged from 24.84 to 178.48 mg L -1 . For aluminum phosphate, the values obtained ranged from 7.68 to 29.68 mg L -1 . The most efficient isolate solubilized 17.86% of the P in the tricalcium phosphate. The isolates LEM 10 and LEM 36 presented distinct capacities to solubilize the different types of RP tested. The susceptibility to microbial solubilization decreased in the following order: Gafsa > Araxá > Abaeté > Catalão > Aipe > Patos > Itafós > Crandalita. The average percentages of solubilized P ranged from 0.25% for Crandalita to 25% for Gafsa. Inoculation with some bacterial isolates promoted maximum gains in RDMC and TDM of 1,137 and 695%, respectively, compared to the uninoculated control treatment. Inoculation with PGPB isolates increased the content and NUE of all macronutrients evaluated. Concerning P and N, in RDMC, the contents of these nutrients showed maximum increases due to bacterial inoculation of 644 and 505%, respectively. As for calcium, the maximum gains corresponded to 572.8% in RDMC. The cluster and principal component analyzes revealed three groups of PGPB, with the isolate with the best performance being Bacillus cereus GC subgroup B (LEM 29). In addition to the diazotrophic activity, the cultures obtained showed the ability to solubilize less reactive phosphorus sources, constituting a tool with potential application in forest nurseries. Keywords: Titratable acidity. Macronutrients. Plant nutrition. pH. Phosphate solubilization.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Impacto do biochar de café sobre as atividades enzimáticas e biomassa microbiana em neossolo cultivados com milho e feijão

A aplicação do biochar na produção de feijão tem sido utilizada com o intuito de potencializar o rendimento desta cultura. No Nordeste, o milho é um dos produtos agrícolas mais importantes, pois participa na formação da renda do agricultor e contribui na alimentação dos animais. O uso de biochar pode trazer benefícios ao solo e ao meio ambiente, como a atuação no sequestro de carbono em longo prazo mitigando os efeitos das alterações climáticas e também apresenta um maior rendimento para a cultura. O objetivo deste estudo é observar os efeitos dos dois tipos de biochar de resíduos de café, em diferentes doses, sobre o crescimento inicial do feijão e do milho e o impacto sobre os atributos químicos, carbono da biomassa microbiana e sobre as atividades enzimáticas absolutas e específicas em um Neossolo Regolítico. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 2x4+1 sendo dois tipos de resíduos borra de café (BC) e casca de café (CC), e 4 doses de cada e mais um controle, sendo EB= dose 0, EBC4, EBC8, EBC12 e EBC16 = biochar de borra de café, nas doses de 4, 8, 12 e 16 Mg ha-1, respectivamente; ECC4, ECC8, ECC12 e ECC16 = biochar de casca de café nas doses de 4, 8, 12 e 16 Mg ha-1. Todos os tratamentos receberam adubação orgânica, esterco bovino. Aos 45 dias após a semeadura, foram avaliada altura, diâmetro, massa seca da parte aérea, química do solo, carbono orgânico total (COT), carbono da biomassa microbiana (CBM), enzimas absolutas (β-glucosidade, urease, fosfatase ácida e fosfatase alcalina) e especificas. A maioria dos parâmetros avaliados apresentou influência positiva quando adicionado o biochar ao solo nas concentrações elevadas de doses EBC12, EBC16, ECC12 e ECC16. Ao analisar o CBM, os tratamentos EBC16 e ECC12 obtiveram um aumento significativo de 100,01 e 116,28%, respectivamente, em relação ao controle (EB). Percebe-se que o solo que recebeu EBC8, cultivado com milho se destacou consideravelmente em relação à fosfatase com um acréscimo de 216,86% com relação ao controle (EB). A enzima especifica tanto pelo carbono da biomassa microbiana como pelo carbono orgânico total apresentaram respostas ao resíduo de café. O biochar produzido a partir de resíduos do café incrementou de forma geral os atributos químico, físicos, microbiano e bioquímicos de solo arenoso cultivado com feijão e milho. Recomenda-se o aproveitamento de resíduos da indústria de café para a produção do biochar e aplicação na cultura do feijoeiro e do milho em doses a partir de 16 Mg ha-1.The application of biochar in bean production has been used to enhance the production of this crop. In the Northeast, maize is one of the most important agricultural products, as it participates in the formation of the income of the farmers and contributes in the feeding of the animals. The use of biochar can bring benefits to the soil and the environment, such as long-term carbon sequestration minimizing the effects of climatic changes, as also presenting a higher yield for the crop. The objective of this study is to observe the effects of the two different types of biochar produced with coffee residues, in different doses, on initial bean and maize growth and the impact on chemical attributes, such as microbial biomass carbon, absolute and enzymatic activities in a Regolithic Neosol cultivated with beans and maize. The experimental design was completely randomized, in a 2x4+1 factorial scheme, being two types of waste coffee grounds (CG), and coffee husks (CH), and 4 doses of each and one control. Being BM= dose 0, and MCG4, MCG8, MCG12 and MCG16 = biochar of coffee grounds, in the doses of 4, 8, 12 and 16, Mg ha-1, respectively; MCH4, MCH8, MCH12 and MCH16 = coffee husks in the doses of 4, 8, 12 and 16 Mg ha-1. All treatments received organic fertilization, bovine manure. At 45 days after sowing, height, diameter, shoot dry matter, soil chemistry, total organic carbon (SOC), microbial biomass carbon (MBC), and absolute and specific enzymes were verified. Most of the evaluated parameters had a positive influence when adding the biochar to the soil at the higher concentrations of MCG12, MCG16, MCH12 and MCH16 doses. When analyzing the MBC, the treatments MCG16 and MCH12 obtained a significant increase of 100.01 and 116.28%, respectively, when compared to the control (CM). It is noticed that the soil that received MCG8, cultivated with maize, stood out considerably in relation to phosphatase with an increase of 216.86% in relation to the control (CM). The enzymes specific for both the carbon of the microbial biomass and the total organic carbon presented responses to the coffee residue. The biochar produced from coffee residues increased in general the chemical, physical, microbial and biochemical attributes of sandy soil cultivated with beans and maize. It is recommended the use of residues from the coffee industry for the production of biochar and application in the bean and maize crop in doses from 16 Mg ha-1.Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNP

SOIL MICROBIOLOGICAL ACTIVITY AND PRODUCTIVITY OF MAIZE FODDER WITH LEGUMES AND MANURE DOSES

Maize is an important cereal and it is widely consumed in the world, both as food for humans and animals. Nitrogen (N) is a nutrient required in large quantities by maize, but unfortunately, soils are limited in meeting this need. Nodulating legumes can serve as a source of Nitrogen, because they are symbiotically associated with bacteria capable of fixing atmospheric N. Another important source of this nutrient is cattle manure, which is widely used in agriculture. The objective of the present study was to evaluate the effect of using legumes and cattle manure on the production as well as the microbial and biochemical quality of the soil used for maize cultivation. The experiment was conducted using a randomized complete block design, in a sub-subdivided plot scheme (2x4) +2, two leguminous plants (pigeon pea and macassar bean), four doses of cattle manure (0, 20, 40 and 60 t ha-1) and two controls; one with mineral fertilization and the other cultivated without the use of fertilizers. Treatment using a manure dose of 60t ha-1 and pigeon pea legume, recorded higher dry mass production per plant. The increase in manure doses was directly proportional to the length and weight of the cobs for the two legumes. The enzymatic activities were affected by the different doses and legumes, with greater results being recorded at the 60 t ha-1 dose with the macassar legume. The use of legumes with manure improved maize production as well as the microbiological and biochemical quality of soils

Effect of biochar on physicochemical properties of a sandy soil and maize growth in a greenhouse experiment

International audienceNumerous studies have been conducted worldwide and more specifically in Brazil assessing the consequences of biochar amendments on the soil properties and on the agronomical production. The present study aimed to evaluate the effects of biochar of coffee residues on the physicochemical characteristics of an Entisol and water use efficiency of maize (Zea mays). Two types of biochar were produced with both coffee ground (CG) and coffee husk (CH) and their physicochemical properties were characterized. A greenhouse pot experiment, quantifying the growth of maize, with different rates of biochar amendments and fertilizing procedures was conducted in a completely randomized design. Treatments consisted in four replications of (i) control (native soil), (ii) synthetic fertilization and (iii) organic fertilization with cow manure, and (iv) the two types of biochar in four doses (4, 8, 12 and 16 Mg ha− 1). Specific surface area (SSA) of CH was significantly higher than CG biochar but both types of biochar had higher SSA than soil. Nutrient and water retention properties of soil and maize growth were significantly improved with increasing biochar doses. The water use efficiency was 50% higher for the treatment with the highest dose of biochar. This is a significant found considering the potential of growing maize on a sandy soil in a dry regions of Brazil. Nutrient use efficiency as well as the C content in Entisol were largely improved by the use of biochar. Determination of SSA was a quick and robust method to anticipate the benefits of biochar on water retention of soil

Impact of coffee biochar on soil carbon, microbial biomass and enzymatic activities in Semiarid Entisol cultivated with maize

International audienceThe melon belongs to the family of commercially important cucurbitaceous in the world. However, the production of this crop can be very problematic in some places due to management practices and the climatic instability. Amongst the different options available to overcome these obstacles, the use of biochar often promoted for providing multiple benefits to crops, could contribute in holding more water and nutrients in soil and therefore improve the plant growth. A second way to try to improve the plant development was to use Trichoderma (TRI) known as aiding in seed germination, and being an excellent biological control agent against plant pathogenic pests. So, the objective of this study was to evaluate the benefits of the association of biochar and TRI on the initial growth of melon and the effects on the quality of a sandy Entisol. We quantified the effects of these associations through biometric growth in melon plants and chemical, microbial, and enzymatic activities of the biogeochemical cycles in the soil. An experiment in a completely of randomized design was performed in a factorial scheme (3 x 2 + 1) with three sources of biochar (bean husk (BH), coffee ground (CG), and coffee husk (CH)) inoculated with (T+) or without (T-) TRI and additional controls When the coffee grounds (CG) and bean husks (BH) biochar with T+ soil was inoculated, the fresh weight (number of leaves), dry weight, length (of roots and branch), soil acid and alkaline phosphatase, total organic carbon, phosphorus, magnesium, potassium, and pH were all increased. Moreover, T. aureoviride inoculated CG biochar compared to the control increased the shoot length and dry biomass of the melon plant in 30 and 22% between 22 and 30 %. The soil that received coffee husks (CH) biochar and T+ showed higher microbial biomass carbon. However, the melon plants responded more to the type of biochar than to the T. aureoviride inoculation, possibly due to the short growth time of melon. Results of BH biochar inoculated with T. aureviride in sandy soil showed improved efficiency on melon growth and increased soil quality

Microbial biomass and enzymatic activities in sandy soil cultivated with lettuce inoculated with plant growth promoters

Plant growth promoter microorganisms have been studied as important tools for increasing crop production. Lettuce is the most consumed hardwood crop in the world. Numerous microorganisms are capable of acting in a beneficial way in the growth of this culture. The objective of the present study was to evaluate the efficacy of Trichoderma and Pseudomonas on the microbial biomass, enzymatic activities in sandy soil and lettuce production. The experimental design was completely randomized with ten replicates and treatments: CONT (absolute control); CM (control with cattle manure fertilization); CMB (with fertilization and Pseudomonas sp.); CMF (with fertilization and T. aureoviride) and CMBF (with fertilization and the two microorganisms combined). The fertilizer used was organic with cattle manure in a dose recommended for the culture. This study evaluated the production of lettuce, microbial biomass and the enzymatic activity of acid phosphatase, alkaline phosphatase and urease. The combined application of CMBF was efficient in increasing lettuce production, because it increased 85% of the cv. Veronica cultivated on sandy soil. The combined use of plant growth promoting microorganisms resulted to an increase in microbial biomass. In lettuce crops, it is recommended to use T. aureoviride URM 5158 and Pseudomonas sp. UAGF 14 in lettuce crops, because improved lettuce production, improves the biochemical quality of soils measured by absolute and specific enzymatic activities per unit of microbial biomass.Os micro-organismos promotores do crescimento de plantas vêm sendo estudados como uma importante ferramenta para o aumento da produção agrícola. Lactuca sativa (alface) é a hortaliça folhosa mais consumida em todo mundo. Inúmeros micro-organismos podem atuar de forma benéfica no crescimento desta cultura. O objetivo do presente trabalho foi avaliar a eficácia de isolados de Trichoderma e Pseudomonas sp. na biomassa microbiana, atividades enzimáticas em solo arenoso e produção da alface cultivada com alface. O experimento foi conduzido em delineamento experimental inteiramente casualizado com dez repetições, sendo os tratamentos: CONT (controle absoluto); CM (controle apenas com a fertilização); CMB (com fertilização e Pseudomonas sp.); CMF (com fertilização e T. aureoviride) e CMBF (com fertilização e os dois micro-organismos combinados). A fertilização utilizada foi a orgânica pela adição de esterco bovino em dose recomendada para a cultura. Avaliou-se a produção de alface, a biomassa microbiana e a atividade enzimática da fostafase ácida, fosfatase alcalina e urease. A aplicação CMBF foi eficiente para o aumento na produção de alface, pois incrementou 85% da produção da cv. Verônica em solo arenoso. O uso combinado de micro-organismos promotores de crescimento de plantas incrementam a biomassa microbiana. Recomenda-se o uso de T. aureoviride URM 5158 e Pseudomonas sp. UAGF 14 no cultivo de alface, pois além de melhorar a produção, melhora a qualidade bioquímica dos solos mensurados por atividades enzimáticas absolutas e específicas por unidade de biomassa microbiana

Coffee waste as an eco-friendly and low-cost alternative for biochar production impacts on sandy soil chemical attributes and microbial gene abundance

International audienceBiochar is a material produced by the pyrolysis of agro-industrial waste, which has become one of the most promising management tools to improve soil quality. The aim was to determine the effects of incorporating biochar from different coffee wastes in sandy soil, cropped with maize, on soil chemical and microbial attributes. The experiment followed a factorial design 2 × 3 + 1 with two types of biochar, including coffee ground (CG) or coffee husk (CH) in 3 doses (4, 8, and 16 t·ha-1) and a control fertilized solely with bovine manure (3 t·ha-1). The variables analyzed were soil organic carbon, chemical attributes, microbial biomass (C, N and P), soil basal respiration and microbial gene abundance (16S rRNA, 18S rRNA and nifH gene). Most chemical attributes were strongly increased by CH application, while CG at 8 t·ha-1 increased the soil C:N ratio (3.5 times), P (2.1 times) and K+ (7.9 times) and at 4 t·ha-1 increased the C content, microbial biomass C and N (3, 2.1 and 1.6 times, respectively). The application of CG biochar at 16 t·ha-1 showed trend to increase the abundance of bacteria, fungi and diazotrophic genes (11, 10 and 2%, respectively). Contribution of both coffee biochar types, but mainly CH, was more effective than the soil that received organic manure alone. Biochar from coffee wastes is a promising tool to improve sandy soil quality