ABSTRACT Forty isolates of endophytic bacteria isolated from banana tree roots were assessed as to their capacity to solubilize phosphate in a solid culture medium supplemented with different inorganic and one organic source of phosphorus. The amount of phosphorus (P) in each liquid medium was quantified, and an indirect assessment of acid phosphatase activity was performed. All assays had a fully randomized design, with three repetitions. Approximately 67.5% of the 40 isolates assessed in solid medium solubilized phosphorus from tricalcium phosphate and 7.5% of the isolates solubilized phosphorus from soy lecithin; no isolates exhibited P solubilization capacity in medium supplemented with iron phosphate. Acid phosphatase activity was detected in 65% of the isolates; Aneurinibacillus sp. and Lysinibacillus sp. isolates presented with the best solubilization indexes. All of the assessed isolates exhibited a capacity to reduce the potential of hydrogen in liquid medium supplemented with tricalcium phosphate. Isolate EB. 78 (Bacillus sp.) exhibited P solubilization capacity in solid media when Ca3(PO4)2 and soy lecithin were used as P sources; this isolate significantly reduced the pH of the liquid medium and exhibited acid phosphatase activity. The results of the present study highlight isolates that exhibit variations in their capacity to solubilize P. These isolates should be used in future tests to assess their field performance.

RESUMO: Agentes de controle biológico associados com matéria orgânica é uma estratégia que pode potencializar o controle dos nematoides-das-galhas. Objetivou-se neste trabalho avaliar o efeito de materiais orgânicos e rizobactérias sobre Meloidogyne javanica em tomateiro. Utilizou-se o delineamento em blocos casualizados, em esquema fatorial 4x2+1, sendo quatro materiais orgânicos (turfa, biofertilizante, esterco bovino e composto orgânico de casca de pequi), dois isolados de rizobactérias (Bacillus pumilus -1 e B. pumilus - 76) e adubação mineral (tratamento adicional), com oito repetições. Mudas de tomateiro foram transplantadas para vasos contendo solo arenoso, ao qual incorporaram-se os diferentes materiais orgânicos. As suspensões das rizobactérias (OD 540=0,5) foram aplicadas ao solo via rega. O solo de cada vaso foi infestado com aproximadamente 3000 ovos e eventuais juvenis de segundo estádio de M. javanica. Todos os materiais orgânicos associados às rizobactérias reduziram o número de galhas e massas de ovos de M. javanica em comparação à adubação mineral. Já o número de juvenis (J2) foi menor nas combinações pequi + B. pumilus-1 e B. pumilus-76 e turfa + B. pumilus-1. O número de ovos e o fator de reprodução foram influenciados pela interação entre as rizobactérias e os compostos. Para o composto de pequi, B. pumilus-1 promoveu menor número de ovos por grama de raiz, enquanto para turfa, B. pumilus-76 foi a mais eficiente. Para o fator de reprodução, apenas o esterco foi influenciado pela bactéria, sendo que B. pumilus-1 foi a que proporcionou menor capacidade reprodutiva do nematoide.

ABSTRACT: Biological control agents associated with organic matter is a strategy that can enhance the control of root-knot nematode. The objective of this study was to evaluate the effect of organic materials and rhizobacteria on Meloidogyne javanica on tomato. We used the randomized block design, in a 4x2+1 factorial scheme, four organic materials (peat, bio-fertilizer, manure and organic compound of pequi hulls), two isolates of rhizobacteria (Bacillus pumilus-1 and B. pumilus-76) and mineral fertilization alone (additional treatment), with eight replications. Tomato seedlings were transplanted to pots containing sandy soil, in which the different organic materials were incorporated. Suspensions of rhizobacteria (OD 540=0,5) were applied to soil by means of irrigation. The soil in each pot was infested with approximately 3,000 eggs and eventual second stage juveniles (J2) of M. javanica. All organic materials associated with rhizobacteria reduced the number of galls and masses of M. javanica eggs compared to mineral fertilizer. The number of juveniles (J2) was lower in combinations pequi + B. pumilus-1 and B. pumilus-76 and peat + B. pumilus-1. The number of eggs and the reproduction factor were influenced by the interaction between rhizobacteria and organic materials. For the compound of pequi, B. pumilus-1 produced a lower number of eggs per gram of root, while for peat, B. pumilus-76 was the most efficient. For the reproduction factor, only the manure was influenced by the bacterium, and B. pumilus-1 was the one that provided lower reproductive capacity of the nematode.

O fósforo é primordial para as plantas forrageiras enquanto a adubação combinada com fontes fosfatadas reativas e naturais podem aumentar a qualidade e a produção do capim Piatã. Objetivou-se avaliar a produção e a relação entre os componentes do capim Piatã submetido a diferentes combinações de fosfato reativo e natural. O experimento foi conduzido em casa de vegetação sob blocos casualizados, com sete repetições. Os tratamentos consistiram de quatro combinações de fontes de fosfato reativo e natural (equivalente a 70 kg ha-1 de P2O5): ausência de adubação fosfatada (controle); adubação com fosfato natural reativo Argélia; adubação com 50% de fosfato natural reativo Argélia e 50% de superfosfato simples e adubação com superfosfato simples. O capim Piatã foi cultivado durante três cortes para caracterização da produção de matéria seca de perfilhos, folhas, pseudocolmo, raízes e relações entre folha/pseudocolmo e parte aérea/raiz. A adubação fosfatada, independentemente da fonte, propiciou incremento na produção da matéria seca das folhas, pseudocolmo e da parte aérea do capim Piatã nos segundo e terceiro cortes avaliativos e na média dos cortes, indicando aumento da produção de forragem.

Phosphorus is essential for forage crops and fertilization combined with reactive and natural sources of phosphorus can increase the quality and yield of Piata grass. The objective of this study was to evaluate the production and the relationship between the components of Piata grass subjected to different combinations of reactive and rock phosphate. The experiment was conducted in a greenhouse in a randomized block design with seven replications. Treatments consisted of four combinations of sources and reactive phosphate rock (equivalent to 70 kg ha-1 of P2O5): absence of phosphate fertilizer (control); fertilization with Algeria reactive rock phosphate; fertilization with 50% of Algeria reactive rock phosphate and 50% fertilization with single superphosphate and single superphosphate fertilization. The Piata grass was grown for three cuttings for characterization of dry matter production of tillers, leaves, pseudostem, relations between roots and leaf/pseudostem and shoot/root part. Phosphorus fertilization, regardless of the source, provided an increment in the production of dry matter of leaves, pseudostem and shoots of Piata grass in the second and third cuttings of evaluation and on the average, indicating increased forage production.