CARACTERÍSTICAS QUÍMICAS Y TEXTURALES DE LOS SUELOS BAJO MANIPULACIÓN DIFERENTE EN UN ÁREA DE ACUERDO EN LA PARAENSA DEL SURESTE

Os solos paraenses tendem apresentar limitações para o desenvolvimento das culturas agrícolas.O presente estudo tem como objetivo avaliar as características químicas e texturais de solo submetido a distintas formas de manejo no Projeto de Assentamento 26 de Março, Marabá-PA. Foi realizada a coleta de amostra composta de solo em setembro de 2016, nas profundidades de 0-20 cm nas áreas de pastagem, cultivo de acerola, área de preservação permanente e floresta plantada e 20-40 cm apenas nas áreas de cultivo de acerola e floresta. Os dados foram interpretados de acordo com referenciais técnicos de análise química e física do solo. Predomina solos distróficos de textura média a arenosa, ressaltando a necessidade de adoção de estratégias de manejo e conservação dos solos.  Para soils tend to have limitations for the development of agricultural crops. The present study aims to evaluate the chemical and textural characteristics of soil submitted to different forms of management in the Settlement Project 26 de Março, Marabá-PA.The collection of a sample composed of soil at a depth of 0-20 was carried out in the following areas: pasture, acerola cultivation, permanent preservation area and planted forest and 20-40 cm in acerola cultivation area and planted   forest   in   September   2016.   The   data   were interpreted according to technical references of chemical and physical analysis of the soil.Dystrophic soils with a medium to sandy texture predominate, emphasizing the need to adopt soil management and conservation strategies.  Los para suelos tienden a tener limitaciones para el desarrollo de cultivos agrícolas. El presente estudio tiene como objetivo evaluar las características químicas y texturales de suelos sometidos a diferentes formas de manejo en el Proyecto Asentamiento 26 de Março, Marabá-PA. Se realizó una muestra de suelo compuesto a una profundidad de 0-20 en las siguientes áreas: pastos, cultivo de acerola, área de preservación permanente y bosque plantado y 20-40 cm de superficie de cultivo de acerola y bosque plantado en septiembre de 2016Predominan suelos distróficos de textura media a arenosa, enfatizando la necesidad de adoptar estrategias de manejo y conservación de suelos. 

Promoção do crescimento vegetal e diversidade genética de bactérias isoladas de nódulos de feijão‑caupi

The objective of this work was to evaluate the potential for plant growth promotion and the genetic diversity of bacteria isolated from nodules of cowpea grown in Cerrado soils in the state of Piauí, Brazil. Twenty‑six strains were evaluated as to their ability to fixate free‑living nitrogen, solubilize inorganic phosphates, produce indole‑3‑acetic acid (IAA) in the absence and presence of tryptophan (100 mg L-1), produce nodules, and promote cowpea growth in Leonard jars. No strain was able to fixate free‑living nitrogen, and 69% were able to solubilize calcium phosphate in vitro. In the presence of tryptophan, all strains were able to synthesize IAA in the 79 medium, and 80% synthesized IAA in the DYGS medium. Only four strains nodulated cowpea. The sequencing of the 16S rRNA gene identified the nodulating strains as belonging to the genera Bradyrhizobium, Rhizobium, Bacillus, and Paenibacillus. Among the non‑nodulating strains able to promote cowpea growth are the genera Bacillus and Paenibacillus.O objetivo deste trabalho foi avaliar o potencial de promoção do crescimento vegetal e a diversidade genética de bactérias isoladas de nódulos de feijão‑caupi cultivado em solos do Cerrado piauiense. Avaliaram-se 26 estirpes quanto à capacidade de fixar nitrogênio em vida livre, solubilizar fosfatos inorgânicos, produzir ácido‑3‑indolacético (AIA) na ausência e na presença do aminoácido triptofano (100 mg L-1), produzir nódulos e promover o crescimento de feijão‑caupi em vasos Leonard. Nenhuma estirpe fixou nitrogênio em vida livre, e 69% foram capazes de solubilizar fosfato de cálcio in vitro. Na presença de triptofano, todas as estirpes foram capazes de sintetizar o AIA em meio 79, e 80% sintetizaram o AIA em meio DYGS. Apenas quatro estirpes nodularam o feijão‑caupi. O sequenciamento do gene 16S rRNA identificou as estirpes nodulíferas como pertencentes aos gêneros Bradyrhizobium, Rhizobium, Bacillus e Paenibacillus. Entre as estirpes não nodulíferas promotoras do crescimento do feijão‑caupi, estão os gêneros Bacillus e Paenibacillus

Growth promotion of common bean and genetic diversity of bacteria from Amazon pastureland

A significant number of bacterial species, particularly in the rhizosphere, may benefit plant growth and development. This group of bacteria is known as plant growth-promoting rhizobacteria (PGPR). This study identified genetically isolates of common bean nodules used to trap bacteria from Amazon pastureland and investigated their capacity of nodulating and promoting growth of common bean when inoculated or co-inoculated with CIAT899 strain (Rhizobium tropici). Two experiments were carried out in a greenhouse, in axenic conditions, using the common bean cultivar Talismã. In the first experiment, 56 PGPR strains were evaluated individually regarding growth promotion and nodulation. In the second experiment, inoculation of seven PGPR strains previously selected in the first experiment was evaluated in three forms of N supply: Co-inoculation with CIAT 899 in the presence of low N-mineral concentration; individual inoculation in the presence of high N-mineral concentration; and individual inoculation in the presence of low N-mineral concentration. The 16S rRNA gene sequencing showed predominance of Pseudomonas genus, identified in 35 % of the sequenced strains. Other genera were identified: Rhizobium, Burkholderia, Xanthomonas and Bacillus. Inoculation of the seven strains with CIAT 899 promoted distinct plant growth in different forms of N supply. In addition, N-mineral supply can be replaced by co-inoculation with strains of Pseudomonas sp. (UFLA 02-281 and UFLA 02-293) and Bacillus sp. (UFLA 02-298) identified in this study

Growth promotion of common bean and genetic diversity of bacteria from Amazon pastureland

ABSTRACT: A significant number of bacterial species, particularly in the rhizosphere, may benefit plant growth and development. This group of bacteria is known as plant growth-promoting rhizobacteria (PGPR). This study identified genetically isolates of common bean nodules used to trap bacteria from Amazon pastureland and investigated their capacity of nodulating and promoting growth of common bean when inoculated or co-inoculated with CIAT899 strain (Rhizobium tropici). Two experiments were carried out in a greenhouse, in axenic conditions, using the common bean cultivar Talismã. In the first experiment, 56 PGPR strains were evaluated individually regarding growth promotion and nodulation. In the second experiment, inoculation of seven PGPR strains previously selected in the first experiment was evaluated in three forms of N supply: Co-inoculation with CIAT 899 in the presence of low N-mineral concentration; individual inoculation in the presence of high N-mineral concentration; and individual inoculation in the presence of low N-mineral concentration. The 16S rRNA gene sequencing showed predominance of Pseudomonas genus, identified in 35 % of the sequenced strains. Other genera were identified: Rhizobium, Burkholderia, Xanthomonas and Bacillus. Inoculation of the seven strains with CIAT 899 promoted distinct plant growth in different forms of N supply. In addition, N-mineral supply can be replaced by co-inoculation with strains of Pseudomonas sp. (UFLA 02-281 and UFLA 02-293) and Bacillus sp. (UFLA 02-298) identified in this study

Crescimento e produtividade de feijão-caupi cultivar BRS Guariba inoculado com estirpes de rizóbio no sudoeste do Piauí

The interaction of cowpea with efficient strains of rhizobia in biological nitrogen fixation can allow increased yield, which can completely replace nitrogen fertilization and can reduce production costs. The aim of this study was to evaluate the response of cowpea cultivar BRS Guariba to inoculation with six strains of rhizobia (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 and BR 3262) in a field experiment conducted in the Southwest of Piauí. The experimental design was randomized blocks with eight treatments and four replicates, including the six cited strains and two uninoculated controls, one with mineral nitrogen (70 kg ha-1) and the other without mineral nitrogen. Nodulation, growth, yield, nitrogen accumulation in shoots and in grains and crude protein content in grains were evaluated. Strains under selection (UFLA 03-154 and UFLA 03-164) promoted yields that were higher compared to those obtained by strains authorized as inoculants (INPA 03-11B, BR 3267 and BR 3262). Inoculation with strains UFLA 03-84, UFLA 03-154 and UFLA 03-164 promoted yields equivalent to the control with mineral nitrogen (796.51 kg ha-1) and similar to the yield obtained with the control without mineral nitrogen and without inoculation, indicating efficient symbiosis of the indigenous rhizobia. UFLA 03-154 was better than the other treatments in terms of increased crude protein. A interação do feijão-caupi com estirpes de rizóbio eficientes na fixação biológica de nitrogênio pode permitir o aumento da sua produtividade, sendo possível substituir totalmente a adubação nitrogenada e reduzir os custos de produção. Objetivou-se avaliar a resposta do feijão-caupi cultivar BRS Guariba à inoculação com seis estirpes de rizóbio (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 e BR 3262) em experimento conduzido em campo no Sudoeste do Piauí. O delineamento experimental foi em blocos casualizados com oito tratamentos e quatro repetições, sendo as seis estirpes citadas e dois controles não inoculados, um com nitrogênio mineral (70 kg ha-1) e outro sem nitrogênio mineral. Foram avaliados nodulação, crescimento, produtividade, acúmulo de nitrogênio na parte aérea e nos grãos e o teor de proteína bruta nos grãos. As estirpes em fase de seleção (UFLA 03-154 e UFLA 03-164) promoveram rendimento de grãos superiores aos obtidos pelas estirpes autorizadas como inoculantes (INPA 03-11B, BR 3267 e BR 3262). As inoculações com as estirpes UFLA 03-84, UFLA 03-154 e UFLA 03-164 proporcionam rendimento de grãos equivalentes ao controle com nitrogênio mineral (796,51 kg ha-1), porém, semelhantes ao rendimento obtido com o controle sem nitrogênio mineral e sem inoculação, indicando boa eficiência simbiótica das populações nativas de rizóbio. A UFLA 03-154 destacou-se dos demais tratamentos com relação ao aumento de proteína bruta