Método rápido de identificação dos nódulos produzidos pelo inoculante, eficiência na fixação do N2 e inoculação cruzada em leguminosas tropicais

Experiments using leonard jars, soil pots, and field experiments were conducted to observe cross-inoculation in some tropical legumes, the possibility of using black nodule-producing strains for identification of Rhizobium nodules and also the efficiency of such strains in nitrogen fixation. The tropical legumes used were: glycine (Neotonia wightii), lablab (Lablab purpureus), centro (Centrosema pubescens), tropical kudzu (Pueraria phaseoloides) and calopo (Calopogonium mucunoides), inoculated with black nodule-producing strains and normal strains. In cross-inoculation behavior certain host specificity was observed in centro. Lablab and calopo formed black nodules with all black nodule-producing strains, centro with C-102 and CM-7, and glycine produced no black nodules. Strains showed differences in nitrogen fixation efficiency and, in a general way, black nodule-producing strains showed highest efficiency in nitrogen fixation. Results indicated that the black nodule-producing strains may be used in Rhizobium strain identification. Foram conduzidos experimentos em vasos-de-leonard, em vasos com solo, e em campo, para verificar a inoculação cruzada, o uso de estirpes formadoras de nódulos pretos na identificação do Rhizobium do inoculante, e sua eficiência na fixação do N2. Foram usadas as leguminosas labe-labe (Lablab purpureus), kudzu tropical (Pueraria phaseoloides), calopogônio (Calopogonium mucunoides), centrosema (Centrosema pubescens), e soja perene (Neotonia wightii), inoculadas com estirpes formadoras de nódulos pretos e de nódulos de coloração normal. Na inoculação cruzada, centrosema mostrou maior grau de especificidade hospedeira. Labe-labe e calopogônio formaram nódulos pretos com todas as estirpes formadoras de nódulos pretos, centrosema e kudzu tropical com as estirpes C-102 e CM-7, e soja perene não apresentou nódulos com esta característica. As estirpes apresentaram diferença na eficiência da fixação do N2 com as estirpes formadoras de nódulos pretos, mostrando-se, em geral, mais eficazes. Os resultados indicaram que as estirpes formadoras de nódulos pretos podem ser usadas para identificar os nódulos produzidos pelo Rhizobium do inoculante.

Fertilizante microbiano com rochas de P e K sobre nutrientes da alface e atributos do solo em cultivos consecutivos

The objective of this work was to evaluate the effect of a microbial fertilizer, produced from phosphate and potassic rocks and earthworm compost, as an alternative to conventional fertilizers, on lettuce (Lactuca sativa) nutrients and soil attributes. The experiment was conducted in consecutive cycles (30 and 60 days) in a soil from the Lorca region, in the municipality of Murcia, Spain. The fertilization treatments were: conventional fertilizer, 100% of the recommended rate (RR); microbial fertilizer, 50% of the RR (5 Mg ha-1);microbial fertilizer, 100% of the RR (10 Mg ha-1); microbial fertilizer, 150% of the RR (15 Mg ha-1); and control, without N-P2O5-K2O fertilization. The microbial fertilizers applied at 100 and 150% of the RR showed significant and positive effects, as well as the best results for plant characteristics. The microbial fertilizer increased total N and available P and K compared with the conventional fertilizer. A residual effect was observed in the successive cycle. The effectiveness of the microbial fertilizer shows it is a viable alternative to conventional fertilizers, with positive effects on plant productivity and soil attributes.O objetivo deste trabalho foi avaliar o efeito de fertilizante microbiano, produzido a partir de rochas fosfática e potássica e vermicomposto de minhoca, como alternativa a fertilizantes convencionais, sobre os nutrientes da alface (Lactuca sativa) e os atributos do solo. O experimento foi conduzido em cultivos consecutivos (30 e 60 dias) em solo da região de Lorca, no município de Múrcia, Espanha. Os tratamentos com fertilização foram: fertilizante convencional, 100% da dose recomendada (DR); fertilizante microbiano, 50% da DR (5 Mg ha-1); fertilizante microbiano, 100% da DR (10 Mg ha-1); fertilizante microbiano, 150% da DR (15 Mg ha-1); e controle, sem fertilização com N-P2O5-K2O. Os fertilizantes microbianos aplicados a 100 e 150% da DR apresentaram efeito significativo e positivo, além de os melhores resultados quanto às características das plantas. O fertilizante microbiano aumentou o N total e o P e K disponíveis comparado ao fertilizante convencional. Observou-se efeito residual no ciclo sucessivo. A efetividade do fertilizante microbiano mostra que é alternativa viável a fertilizantes convencionais, com efeitos positivos sobre a produtividade das plantas e os atributos do solo

Growth of Cunninghamella elegans UCP 542 and production of chitin and chitosan using yam bean medium

Microbiological processes were used for chitin and chitosan productions by Cunninghamella elegans (UCP 542) grown in a new economic culture medium. The assay was carried out to evaluate the growth of C. elegans using yam bean ( Pachyrhizus erosus L. Urban) medium, in different times of growth (24, 48, 72 and 96 hrs), incubated at 28\ub0C in an orbital shaker at 150 rpm. The lyophilized biomass was determined by gravimetry. The polysaccharides were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, titration and viscosity. C. elegans grown in the yam bean medium and produced higher yields of biomass (24.3 g/ mL) in 96 hrs. The high level was chitosan (66 mg/g), and chitin (440 mg/g) were produced at 48 and 72 hrs of growth, respectively. The polysaccharides showed degree of deacetilation and viscosimetric molecular weight as: 6.2% and 3.25 x104 g/mol for chitin, and 85% and 2.72 x 104 g/mol for chitosan, respectively. The results obtained suggest high biotechnological potential of yam bean as an economic source to produce chitin and chitosan by C. elegans. In addition, the new medium using yam bean for production of the chitin and chitosan may be used for many purposes to reduce the cost price of fermentation processes

Biodegradation of Paclobutrazol — A Plant Growth Regulator Used in Irrigated Mango Orchard Soil

Paclobutrazol (PBZ), [2RS,3RS]-1-[4-chlorophenyl]-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl) pentan-3-ol, consists of a triazole ring and a benzene ring-chloro linked to a carbon chain open. It is a plant growth regulator widely used in many crops in order to produce fruit throughout the year by inhibiting gibberellin synthesis, a hormone responsible for the vegetative plant growth. Actually, studies are showing that paclobutrazol remains active in the soil for a long time, affecting the growth and development of subsequent crops by reducing plant vigor. Biodegradation is an effective and cheap process that can to degrade or transform contaminants to less toxic or nontoxic. In this work, the biodegradation of paclobutrazol was studied using in submersed culture and saturated and unsaturated soils. In these conditions, experiments with biostimulation and bioaugmentation were performed. In the experiments carried out in submersed culture, with biostimulation by addition of glycerol, the PBZ biodegradation was higher than that with PBZ as sole carbon source. The biodegradation of PBZ in unsaturated soils was more efficient when soil samples with a history of application of PBZ were used. The highest number of applications of PBZ favored biodegradation. The biodiversity of the microbiota in the soil favored the biodegradation of PBZ aromatic rings. PBZ was not seen to be phytotoxic and the biodegraded products increased the germination index

Biofertilizantes com fosfato natural, enxofre e Acidithiobacillus em solo com baixo P disponível

A produção de biofertilizantes é um processo prático e econômico que reduz o consumo de energia e a sua aplicação visa aumentar o fósforo (P) disponível no solo. Biofertilizantes fosfatados (B5, B10, B15, B20) produzidos em laboratório usando fosfato natural (FN) e enxofre em diferentes concentrações (5; 10; 15 e 20%), inoculado com Acidithiobacillus (S*) e enxofre (20%) sem Acidithiobacillus (S), com incubação por 30, 45 e 60 dias, foi utilizado em um experimento em vasos com solo da Zona da Mata de Pernambuco (Argissolo Amarelo), com baixo nível de P disponível, cultivado com jacatupé (Pachyrhizus erosus), por dois períodos consecutivos. Os tratamentos fosfatados foram: fosfato natural (FN); biofertilizantes (B5, B10, B15, B20), com Acidithiobacillus (FN+S*) e B20, sem Acidithiobacillus (FN+S); superfosfato triplo (ST); e um controle sem fósforo (P0). As plantas foram inoculadas com a mistura das estirpes de rizóbio NFB 747 e 748, e sem inoculação. Nos ensaios em laboratório analisou-se o pH e o P extraído dos biofertilizantes, em cada período de incubação, e nos experimentos em vasos com solo determinou-se a biomassa seca, o N e o P total acumulado da parte aérea, o pH e o P extraído do solo. O P disponível foi mais elevado para os biofertilizantes com Acidithiobacillus (FN+S*) e para o superfosfato triplo. A fertilização fosfatada, condicionou resposta positiva dos biofertilizantes (FN+S*) e do superfosfato triplo. Os rizóbios nativos foram tão eficientes quanto os do inoculante. Após os dois cultivos o P disponível foi maior com os biofertilizantes B15 e B20 com Acidithiobacillus.The production of mineral fertilizers is a expensive process, since it requires high energy consumption, and cannot be produced by small farmers. Laboratory assays were conducted to produce P-biofertilizers from natural phosphate (B5, B10, B15, B20), applying sulphur at different rates (5; 10; 15 and 20%) inoculated with Acidithiobacillus (S*) and testing increasing periods of incubation. A greenhouse experiment was carried out to evaluate the effect of the biofertilizers in a soil with low available P (Typic Fragiudult) from the "Zona da Mata" of Pernambuco State, grown with yam bean (Pachyrhizus erosus) in two consecutive harvests. The treatments were: Natural Phosphate (NP); biofertilizers produced in laboratory (B5, B10, B15, B20) with sulphur and Acidithiobacillus (NP+S*); natural phosphate with sulphur (20%) without Acidithiobacillus (NP+S); triple super phosphate (TSP) and a control without phosphorus. Plants were inoculated with a mixture of rhizobia strains (NFB 747 and NFB 748) or did not receive rhizobia inoculation. In bioassays pH and available P in the biofertilizers were analyzed. In the greenhouse experiment shoot dry matter, total N and total P in shoots, soil pH and available P were determined. Higher rates of available P were obtained in biofertilizers with sulphur and Acidithiobacillus (NP+S*) and in triple super phosphate (TSP), and biofertilizers with sulphur and Acidithiobacillus (FN+S*) and triple super phosphate (TSP) increased plant parameters. Native rhizobia were as effective as the strains applied in inoculation. After the two harvests soil presented lower pH values and higher rates of available P when the biofertilizers B15 and B20 with sulphur and Acidithiobacillus were applied

Development and natural nodulation of legume trees in soils from Pernambuco, Brazil

O objetivo deste trabalho foi avaliar o desenvolvimento e nodulação natural de leucena (Leucaena leucocephala), palheteira (Clitoria fairchildiana) e sabiá (Mimosa caesalpiniifolia), em solos com diferentes formas de uso da terra, da Zona da Mata de Pernambuco. Foram utilizados quatro solos de mata, seis solos de áreas agrícolas e dois de áreas degradadas. Os solos foram classificados, analisados quimicamente e distribuídos, 3 kg de solo por vaso, com duas plantas por vaso. A colheita das mudas foi feita aos 76, 70 e 62 dias, para leucena, palheteira e sabiá, respectivamente. O delineamento experimental foi inteiramente casualizado, com 12 tratamentos e 3 repetições. Foram constatadas baixas freqüências de populações nativas de rizóbios para leucena, 22% de plantas noduladas, em comparação à palheteira e sabiá, 100 e 86%, respectivamente. A palheteira apresentou nodulação natural abundante e eficiência na fixação de N2, o que demonstra compatibilidade com as populações nativas de rizóbios. O crescimento, o desenvolvimento, a nodulação e o acúmulo de nitrogênio das três espécies foram favorecidos no solo de área agrícola com cobertura de Calopogonium mucunoides. A palheteira apresentou o maior potencial para fixação de N2 e eficiência da nodulação com populações nativas de rizóbios, seguida por sabiá e leucena.The objective of this work was to evaluate the development and natural nodulation of Leucaena leucocephala, Clitoria fairchildiana and Mimosa caesalpiniifolia, in soils with different type of land use, in Zona da Mata of Pernambuco, Brazil. Soils of four forest areas, six agriculture areas and two degraded areas were used. Soils were classified, analyzed chemically and distributed in pots 3 kg soil per pot, two plants per pot. Plant evaluations were carried out at 76, 70 and 62 days, for L. leucocephala, C. fairchildiana and M. caesalpiniifolia, respectively. The experimental design was completely randomized, with 12 treatments and 3 repetitions. Low frequencies of native populations of rhizobia were verified for L. leucocephala, with 22% of plants nodulated, compared to C. fairchildiana and M. caesalpiniifolia, with 100% and 86%, respectively. M. caesalpiniifolia presented abundant natural nodulation and efficiency in the fixation of N2, demonstrating compatibility with native populations of rhizobia. Growth, development, nodulation as well as accumulation of nitrogen of the three species, were favored with soil under agricultural areas with covering of Calopogonium mucunoides. C. fairchildiana presented greater potential for fixation of N2 and efficiency of the nodulation with native populations of rhizobia followed by M. caesalpiniifolia and L. leucocephala

Rock biofertilizer and earthworm compost on sugarcane performance and soil attributes in two consecutive years

ABSTRACT The deployment of soluble fertilizers has been one of the most commonly applied agricultural practices in the bid to increase crop yield. However, the production of soluble fertilizers has a considerable economic cost and consumes a substantial amount of energy. In general, soil organic matter provides the nutrients needed for plant growth in organic agriculture. However, these nutrients are not sufficient if the best yield is to be obtained. The aim of our field experiment was to evaluate the effectiveness of phosphate and potassic sources (rocks, bio-fertilizers and soluble fertilizers) based on several sugarcane characteristics and soil attributes. Our experiment was conducted over two consecutive years, and we assessed the effect of using sugarcane filter mud cake (SFMC). In addition, we mixed the phosphate and potassic sources with earthworm compost enriched in N by inoculation with diazotrophic bacteria (OM) and applied at 50, 100 and 150 % of the recommended dosage rate (RDR). The PK biofertilizer with OM enriched in N positively affected sugarcane height, yield, and industrial characteristics. The application of SFMC greatly increased available P and K in the soil and plant characteristics with residual effect in the two consecutive harvests. We conclude that the biofertilizer has the potential to increase sugarcane characteristics and may represent an alternative to soluble fertilizers

Seleção de Bradyrhizobium para caupi cultivado em solo ácido (LVA) do semi-árido do Brasil

To evaluate the efficient dinitrogen-fixing ability of Bradyrhizobium spp strains for cowpea, selected in previous assays using Leonard jars at high temperature regime, a greenhouse experiment was carried out with two cowpea cultivars UPA 202 and Pitiuba) growing in an acid LVA sandy-loam texturized soil, located in "Chapada do Araripe", in the semiarid zone of Brazil. Three lime treatments (0, 2 and 4 CaCo3 t/ha) were applied, and seeds were inoculated with NFB 09, NFB 36, NFB 91 and CB 756 strains, with a basal fertilization of phosphorus. The results showed that lime addition (2 t/ha) increased nodulation, total N accumulated and plant dry matter, and 4 t/ha rate decrease all the parameters. Correlation between total N and nodules weight at the various lime rates and with the different strains was observed. Inoculation affected positively nodulation, total N and dry matter yield with NFB 09 showing the best results.Em experimento conduzido em casa de vegetação procurou-se avaliar a adaptação e a seleção de estirpes de Bradyrhizobium spp, de comprovada eficiência, em testes prévios com vasos de Leonard em condições de temperatura elevada. Foram usadas duas cultivares de caupi (IPA 202 e Pitiúba) e um solo ácido (LVA) textura argilo-arenosa, coletado na Serra do Araripe, região semi-árida de Pernambuco. Adicionou-se calcário nos níveis equivalentes a 0,2 e 4 t/ha, e fez-se a inoculação com as estirpes NFB 09, NEB 36, NFB 91 e CB 756, isoladamente, com uma adubação básica fosfatada. A dose de 2 t/ha de CaCo3 aumentou a nodulação, a produção de matéria seca e a quantidade de N total da parte aérea, observando- se decréscimo nestes parâmetros quando aplicada a dose de 4 t/ha de calcário. Houve boa correlação entre a quantidade de N total acumulado na parte aérea e o peso de nódulos nos diferentes níveis de calcário e com as estirpes inoculadas. A inoculação teve efeito positivo na nodulação, na acumulação de N total e no peso de matéria seca, com a estirpe NFB 09 mostrando os melhores resultados