The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil... more The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil) was to examine the influence of the presence of the forage legume Desmodium ovalifolium in pastures of Brachiaria humidicola on the nitrogen recycled through plant litter over stocking rates of 2, 3 and 4 head ha-1. The results demonstrated that the presence of the D. ovalifolium in the pasture significantly increased the protein content of the associated Brachiaria grass, and the rate and quantity of N recycled through the litter pathway. While had no significant increase in animal weight gain due this legume, the increase in N recycled through the litter pathway should provide an increase in the sustainability of pasture production, especially at the lower stocking rate where the grazing pressure was lower and the proportion of legume was higher.
O experimento foi conduzido na Estação de Zootecnia do Extremo Sul (Essul), pertencente a CEPLAC/... more O experimento foi conduzido na Estação de Zootecnia do Extremo Sul (Essul), pertencente a CEPLAC/MAPA, localizada em Itabela-Bahia, com o objetivo de avaliar a massa de forragem e a produção animal nas cultivares (cvs.) de Urochloa humidicola, Tupi, Tully e Llanero, manejadas em lotação contínua, com 15 cm e 25 cm de alturas do dossel. O delineamento experimental foi em blocos casualizados com três repetições, em esquema fatorial, ficando nas parcelas as cultivares e nas subparcelas as alturas. Na área experimental composta de 18 piquetes de 0,77 ha, utilizou-se novilhas de peso vivo médio de 222 kg ± 22,01 kg, com ajuste da lotação visando manter o dossel nas alturas pré-estabelecidas. As cvs. Tupi e Llanero tiveram a massa seca de forragem total (MSFT) e massa seca de forragem verde (MSFV) semelhantes e superiores a cv. Tully. As ofertas de massa seca de forragem total (OFMSFT) e de massa seca de forragem verde (OFMSFV) não diferiram entre as cultivares e tiveram médias de 5,8% e 3,6%, respectivamente. A altura de 25 cm foi a que propiciou maior, MSFT, MSFV, matéria seca de forragem senescente (MSFS), OFMSFT e OFMSFV. No entanto, o ganho de peso por ha por dia (GPHD) e a taxa de lotação (TL) foram maiores na altura de 15 cm. A análise comparativa da produção entre as cultivares mostrou que independentemente de altura de pastejo a produção por ha foi maior na pastagem da cultivar Llanero. Palavras-chave: massa de forragem, oferta de forragem, taxa de lotação, ganho de peso animal. Grazing height, pasture characteristics and animal production in pastures formed by three Urochloa humidicola cultivars. The experiment was carried out at Estação de Zootecnia do Extremo Sul (Essul), belonging to CEPLAC/MAPA, located in Itabela-Bahia, with the objective of evaluating forage mass and animal production in cultivars (cvs.) of Urochloa humidicola, Tupi, Tully and Llanero, managed in continuous stocking, with 15 cm and 25 cm canopy heights. The experimental design was in randomized blocks with three replications, in a factorial scheme, with the cultivars in the plots and the heights in the subplots. In the experimental area composed of 18 paddocks of 0.77 ha, heifers with an average live weight of 222 kg ± 22.01 kg were used, with stocking adjustment aiming to maintain the canopy at pre-established heights. The cvs. Tupi and Llanero had the total forage dry mass (MSFT) and green forage dry mass (MSFV) similar and superior to cv. Tully. The total forage dry mass (OFMSFT) and green forage dry mass (OFMSFV) offers did not differ between cultivars and averaged 5.8% and 3.6%, respectively. The height of 25 cm was the one that provided the highest, MSFT, MSFV, senescent forage dry matter (MSFS), OFMSFT and OFMSFV. However, weight gain per ha per day (GPHD) and stocking rate (TL) were higher at 15 cm height. The comparative analysis of production between cultivars showed that, regardless of grazing height, production per ha was higher in the pasture of cultivar Llanero.
A fixacao biologica de nitrogenio (FBN) e capaz de suprir toda demanda de nitrogenio da soja. A r... more A fixacao biologica de nitrogenio (FBN) e capaz de suprir toda demanda de nitrogenio da soja. A relacao simbiotica mais importante e com B. japonicum e B. elkanii. O objetivo foi avaliar a FBN na soja cultivar BRS 133 inoculada com 4 estirpes de Bradyrhizobium usando inoculante turfoso. O delineamento foi inteiramente casualizado com seis repeticoes. Os tratamentos foram soja inoculada com estirpes de B. japonicum (estirpes USAD110, CPAC15 e CPAC 7), B. elkanii (estirpe 29 W) e sorgo como testemunha. Aos 70 dias apos o plantio procedeu-se com a colheita da parte aerea e raizes das plantas as quais foram secas a 65 o C para determinar a materia seca (MS). As amostras foram processadas em moinho de rolagem ate formar po. Foi determinado o nitrogenio total (N) por meio de digestao Kjeldahl, e a razao isotopica de 15 N/ 14 N pelo metodo de Dumas em analisador automatico de C e N, acoplado a espectrometro de massas. Nao houve diferenca significativa em MS na parte aerea e planta inteira,...
This study evaluated soil parameters involved in ammonia (NH3) fluxes from livestock excreta and ... more This study evaluated soil parameters involved in ammonia (NH3) fluxes from livestock excreta and urea fertilizer. Treatments were distributed in a randomized block design, with five replicates. Treatments included application of 1) urine; 2) dung; or 3) urea fertilizer (50 kg N ha-1) on palisadegrass pasture (Brachiaria brizantha cv. Marandu). Excreta was collected from crossbred heifers grazing palisadegrass pastures. One soil background treatment without excreta or urea was included for the measurement of NH3 fluxes. Treatments were applied in May/2017, April/2018, and Jul/2018. One liter of urine, 1.6 kg of dung, and 2.67 g of urea fertilizer were added inside the chamber according to treatment. Ammonia flux was evaluated using a semi-opened free static chamber and N determination by steam distillation. The extracted solution of fresh soil was analyzed in spectrophotometer. Pearson’s correlation and linear regression analyses were run to identify which soil parameters explained N...
Few options have been found to mitigate nitrous oxide (N2O) emissions in grazing systems, which r... more Few options have been found to mitigate nitrous oxide (N2O) emissions in grazing systems, which requires attention, by the researches. The aim of this study was to determine N2O emissions from excreta of cattle grazed in Marandu-grass pastures (Brachiaria brizantha cv. Marandu) with different sources of nitrogen. The experiment consisted of two factors (pasture management and excreta type) in a randomized complete block design, with 5 replicates. The pastures were: 1) CONTROL: Marandu-grass pastures without nitrogen or legume; 2) FERT: Marandu-grass pastures fertilized with nitrogen (150 kg N haArachis pintoi cv. Amarillo). The excreta types were dung (1.6 kg/ treatment) and urine (1.0 L/ treatment) from heifers (353.1 ± 24.1 kg BW) grazing in the pastures. Static chambers were used to evaluate N2O emissions, which were determined by gas chromatography (electron capture detector), and were integrated over time, to calculate the cumulative emissions and the amount of nitrogen lost as N2O. Posteriorly, ANOVA was performed and the Tukey’s test was ran to determine differences among means. Dung emissions of N2O totaled 1151, 579 and 245 µg N-N2O mP = 0.0052). Urine emissions of N2O were 273, 347 and 275 µg N-N2O m2O emission factor differed between excreta type and was 2.2 times greater for dung than for urine (P = 0.038). For dung, the emission factor (EF) varied from 0.15 to 0.83% N-applied and for urine ranged 0.16% N-applied emitted as N2O. The greatest emissions were observed for FERT. Excreta affected N2O emissions, and in all cases, it was much lower than IPCC default Tier 1 emission factor.
Ammonia (NH3) is a large source of environmental contamination from nitrogen usage. The objective... more Ammonia (NH3) is a large source of environmental contamination from nitrogen usage. The objective of this study was to evaluate NH3 losses from urine and dung of cattle grazed in Marandu-grass pastures (Brachiaria brizantha cv. Marandu) with different sources of nitrogen. The experiment consisted of two factors (pasture management and excreta type) in a randomized complete block design, with 5 replicates. The pastures were: 1) CONTROL: Marandu-grass pastures without nitrogen or legume; 2) FERT: Marandu-grass pastures fertilized with nitrogen (150 kg N ha-1 year-1); 3) MIXED: Marandu-grass pastures intercropped with Pinto peanut (Arachis pintoi cv. Amarillo). The excreta types were dung (1.6 kg/ treatment) and urine (1.0 L/ treatment) from heifers (353.1 ± 24.1 kg BW) grazing in the pastures. Ammonia volatilization was evaluated using semi-opened free static chamber and nitrogen determination by steam distillation. Sampling were performed on 1, 3, 5, 9, 14 and 21 d after treatments being applied to the area. ANOVA was performed for total ammonia volatilized; when differences were observed among means, they were compared using the LSD test. For dung, NH3 losses differed among pasture treatments (P = 0.046). Volatilization losses was greater for FERT pastures (1.04% of applied N) compared with CONTROL (0.83% of applied N) and MIXED (0.81% of applied N) pastures. No differences were observed for urine among treatments for FERT (3.69 of applied N), MIXED (3.63 of applied N) and CONTROL (2.78 of applied N). The NH3 emission factor differed between excreta type (P < 0.0001). Urine averaged 3.40% and dung 0.89% of volatilized N-applied. Urine was the main source of ammonia volatilization, and all estimates of volatilization losses were among the lowest reported in the literature.
Pré-inoculação de sementes de Vigna unguiculata (L) Walp. com inoculante polimérico no Centro-Oes... more Pré-inoculação de sementes de Vigna unguiculata (L) Walp. com inoculante polimérico no Centro-Oeste Pre-inoculation of seed the Vigna unguiculata (L) Walp. with
Mircen Journal of Applied Microbiology and Biotechnology, 1987
... experienced. The distillates are titrated against a sulphuric acid solution (0.05-0.25 N), th... more ... experienced. The distillates are titrated against a sulphuric acid solution (0.05-0.25 N), this acid being standardized by titration against a solution of tris (hydroxymethyl) methylamine (THAM) as suggested by Keeney & Nelson (1982). ...
Soil N 2 O fluxes are frequently assessed by the use of static chambers with a single daily sampl... more Soil N 2 O fluxes are frequently assessed by the use of static chambers with a single daily sampling. In this study, two experiments were conducted in two contrasting climatic locations, one in Edinburgh, UK, and the other at Seropédica, Rio de Janeiro State, Brazil. Soil N 2 O fluxes were monitored every 6 h for 30 days during the summer in Edinburgh by the use of an automatic chamber system, and every 3 h for 5 days at Seropédica, using a manually-sampled static chamber. Air and soil temperatures were also measured at the same time as the N 2 O fluxes. The principal driver of N 2 O flux within any diurnal period was found to be soil temperature. Regression analysis showed that, for both places, the evenings (21:00e22:00 h) and mornings (09:00e10:00 h), were the times that the flux best represented the daily mean. The ability to work in daylight make the morning period the preferred one.
In a paper published recently in this Journal a new equation was presented for the calculation of... more In a paper published recently in this Journal a new equation was presented for the calculation of the proportion of plant nitrogen derived from plant-associated biological nitrogen fixation (BNF) using the ‘A-value’ technique. To apply this technique it is assumed that the specific availability (‘A-value’) of soil N is constant regardless of the quantity of added labelled N fertilizer. The
In the estimation of the contribution of biological nitrogen fixation (BNF) to plant nutrition ma... more In the estimation of the contribution of biological nitrogen fixation (BNF) to plant nutrition many authors have compared the estimates derived from the15N-isotope-dilution technique with those derived from the total N-difference technique. In this paper we show that agreement of these two estimates is mathematically inevitable when the recovery of labelled nitrogen (%FUE) by the “N2-fixing” (test) and control plants
Biological nitrogen fixation (BNF) associated with trees and shrubs plays a major role in the fun... more Biological nitrogen fixation (BNF) associated with trees and shrubs plays a major role in the functioning of many ecosystems, from natural woodlands to plantations and agroforestry systems, but it is surprisingly difficult to quantify the amounts of N2 fixed. Some of the problems involved in measuring N2 fixation by woody perennials include: (a) diversity in occurrence, and large plant-to-plant variation
A introducao de leguminosas em pastagens de gramineas, na forma de consorcio, tem sido apresentad... more A introducao de leguminosas em pastagens de gramineas, na forma de consorcio, tem sido apresentada como uma estrategia para repor as quantidades de N que se tornam indisponiveis para as gramineas ao longo dos anos. O efeito positivo desta pratica para o ganho de producao animal e conhecido porem, ainda sao escassos os resultados que demonstrem que a leguminosa tambem favoreca a um aumento da longevidade da pastagem. Neste trabalho, comparou-se uma pastagem de Brachiaria ruziziensis consorciada com Srylosanthes guianensis com outra de B. ruziziensis em monocultura, com base em parâmetros da propria pastagem e de producao animal. Os resultados mostraram que a pastagem consorciada permitiu um maior ganho de peso animal por area e um continuo ganho de peso dos animais durante todo o periodo de avaliacao. A producao de forragem da pastagem consorciada superou em cerca de 4 t/ha a pastagem de graminea durante o periodo avaliado (abril/97 a outubro/97), o que aparentemente foi resultado de...
Resumo A cultura de capim elefante (Pennisetum purpureum Schum.) é altamente eficiente na fixação... more Resumo A cultura de capim elefante (Pennisetum purpureum Schum.) é altamente eficiente na fixação de CO2 (gás carbônico) atmosférico durante o processo de fotossíntese para a produção de biomassa vegetal. Por ser uma espécie de rápido crescimento, a biomassa de capim-...
The existence of large population of ineffective native rhizobia and inconsistent performance of ... more The existence of large population of ineffective native rhizobia and inconsistent performance of exotic strains in Ghanaian soils necessitate the need to identify effective and locally adapted elite strains for enhanced legume-rhizobium symbiosis. This study was designed to test the suitability of two previously selected potential elite Bradyrhizobium strains for use as inoculants on cowpea (Vigna unguiculata L. Walp) and groundnut (Arachis hypogaea L.) in multilocation experiments. Field experiments were set up at 26 locations (12 planted with cowpea and 14 planted with groundnut) in the Northern region of Ghana. Four treatments were applied at each location: inoculation with Bradyrhizobium strains KNUST 1002 and KNUST 1006, a positive nitrogen (+N) control and a negative control (without nitrogen or inoculation) arranged in randomized complete blocks with four replications. The results showed that inoculation with strains KNUST 1002 and KNUST 1006 promoted significant increases in grain yields of both cowpea and groundnut. On average, inoculating cowpea with strains KNUST 1002 and KNUST 1006 resulted in 63 and 52% increases in grain yield when compared to the negative control. Pod yields of groundnut, on the other hand, were significantly (p < 0.05) increased at 57% of the study locations with one or both test strains. Responses to inoculation were, however, highly variable across the different study locations (i.e., significant Treatment × Location Interaction, TLI). A detailed analysis of this significant TLI based on the genotype main effect (G) plus genotype-by-environment (GE) interaction (GGE) biplot analysis revealed that location contributed 71 and 88% of the variation observed in cowpea and groundnut, respectively, and grouped the locations into mega-environments for cowpea. These results demonstrate that native elite Bradyrhizobium strains KNUST 1002 and KNUST 1006 have potential for use as inoculants to increase cowpea and groundnut production in Northern Ghana.
The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil... more The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil) was to examine the influence of the presence of the forage legume Desmodium ovalifolium in pastures of Brachiaria humidicola on the nitrogen recycled through plant litter over stocking rates of 2, 3 and 4 head ha-1. The results demonstrated that the presence of the D. ovalifolium in the pasture significantly increased the protein content of the associated Brachiaria grass, and the rate and quantity of N recycled through the litter pathway. While had no significant increase in animal weight gain due this legume, the increase in N recycled through the litter pathway should provide an increase in the sustainability of pasture production, especially at the lower stocking rate where the grazing pressure was lower and the proportion of legume was higher.
O experimento foi conduzido na Estação de Zootecnia do Extremo Sul (Essul), pertencente a CEPLAC/... more O experimento foi conduzido na Estação de Zootecnia do Extremo Sul (Essul), pertencente a CEPLAC/MAPA, localizada em Itabela-Bahia, com o objetivo de avaliar a massa de forragem e a produção animal nas cultivares (cvs.) de Urochloa humidicola, Tupi, Tully e Llanero, manejadas em lotação contínua, com 15 cm e 25 cm de alturas do dossel. O delineamento experimental foi em blocos casualizados com três repetições, em esquema fatorial, ficando nas parcelas as cultivares e nas subparcelas as alturas. Na área experimental composta de 18 piquetes de 0,77 ha, utilizou-se novilhas de peso vivo médio de 222 kg ± 22,01 kg, com ajuste da lotação visando manter o dossel nas alturas pré-estabelecidas. As cvs. Tupi e Llanero tiveram a massa seca de forragem total (MSFT) e massa seca de forragem verde (MSFV) semelhantes e superiores a cv. Tully. As ofertas de massa seca de forragem total (OFMSFT) e de massa seca de forragem verde (OFMSFV) não diferiram entre as cultivares e tiveram médias de 5,8% e 3,6%, respectivamente. A altura de 25 cm foi a que propiciou maior, MSFT, MSFV, matéria seca de forragem senescente (MSFS), OFMSFT e OFMSFV. No entanto, o ganho de peso por ha por dia (GPHD) e a taxa de lotação (TL) foram maiores na altura de 15 cm. A análise comparativa da produção entre as cultivares mostrou que independentemente de altura de pastejo a produção por ha foi maior na pastagem da cultivar Llanero. Palavras-chave: massa de forragem, oferta de forragem, taxa de lotação, ganho de peso animal. Grazing height, pasture characteristics and animal production in pastures formed by three Urochloa humidicola cultivars. The experiment was carried out at Estação de Zootecnia do Extremo Sul (Essul), belonging to CEPLAC/MAPA, located in Itabela-Bahia, with the objective of evaluating forage mass and animal production in cultivars (cvs.) of Urochloa humidicola, Tupi, Tully and Llanero, managed in continuous stocking, with 15 cm and 25 cm canopy heights. The experimental design was in randomized blocks with three replications, in a factorial scheme, with the cultivars in the plots and the heights in the subplots. In the experimental area composed of 18 paddocks of 0.77 ha, heifers with an average live weight of 222 kg ± 22.01 kg were used, with stocking adjustment aiming to maintain the canopy at pre-established heights. The cvs. Tupi and Llanero had the total forage dry mass (MSFT) and green forage dry mass (MSFV) similar and superior to cv. Tully. The total forage dry mass (OFMSFT) and green forage dry mass (OFMSFV) offers did not differ between cultivars and averaged 5.8% and 3.6%, respectively. The height of 25 cm was the one that provided the highest, MSFT, MSFV, senescent forage dry matter (MSFS), OFMSFT and OFMSFV. However, weight gain per ha per day (GPHD) and stocking rate (TL) were higher at 15 cm height. The comparative analysis of production between cultivars showed that, regardless of grazing height, production per ha was higher in the pasture of cultivar Llanero.
A fixacao biologica de nitrogenio (FBN) e capaz de suprir toda demanda de nitrogenio da soja. A r... more A fixacao biologica de nitrogenio (FBN) e capaz de suprir toda demanda de nitrogenio da soja. A relacao simbiotica mais importante e com B. japonicum e B. elkanii. O objetivo foi avaliar a FBN na soja cultivar BRS 133 inoculada com 4 estirpes de Bradyrhizobium usando inoculante turfoso. O delineamento foi inteiramente casualizado com seis repeticoes. Os tratamentos foram soja inoculada com estirpes de B. japonicum (estirpes USAD110, CPAC15 e CPAC 7), B. elkanii (estirpe 29 W) e sorgo como testemunha. Aos 70 dias apos o plantio procedeu-se com a colheita da parte aerea e raizes das plantas as quais foram secas a 65 o C para determinar a materia seca (MS). As amostras foram processadas em moinho de rolagem ate formar po. Foi determinado o nitrogenio total (N) por meio de digestao Kjeldahl, e a razao isotopica de 15 N/ 14 N pelo metodo de Dumas em analisador automatico de C e N, acoplado a espectrometro de massas. Nao houve diferenca significativa em MS na parte aerea e planta inteira,...
This study evaluated soil parameters involved in ammonia (NH3) fluxes from livestock excreta and ... more This study evaluated soil parameters involved in ammonia (NH3) fluxes from livestock excreta and urea fertilizer. Treatments were distributed in a randomized block design, with five replicates. Treatments included application of 1) urine; 2) dung; or 3) urea fertilizer (50 kg N ha-1) on palisadegrass pasture (Brachiaria brizantha cv. Marandu). Excreta was collected from crossbred heifers grazing palisadegrass pastures. One soil background treatment without excreta or urea was included for the measurement of NH3 fluxes. Treatments were applied in May/2017, April/2018, and Jul/2018. One liter of urine, 1.6 kg of dung, and 2.67 g of urea fertilizer were added inside the chamber according to treatment. Ammonia flux was evaluated using a semi-opened free static chamber and N determination by steam distillation. The extracted solution of fresh soil was analyzed in spectrophotometer. Pearson’s correlation and linear regression analyses were run to identify which soil parameters explained N...
Few options have been found to mitigate nitrous oxide (N2O) emissions in grazing systems, which r... more Few options have been found to mitigate nitrous oxide (N2O) emissions in grazing systems, which requires attention, by the researches. The aim of this study was to determine N2O emissions from excreta of cattle grazed in Marandu-grass pastures (Brachiaria brizantha cv. Marandu) with different sources of nitrogen. The experiment consisted of two factors (pasture management and excreta type) in a randomized complete block design, with 5 replicates. The pastures were: 1) CONTROL: Marandu-grass pastures without nitrogen or legume; 2) FERT: Marandu-grass pastures fertilized with nitrogen (150 kg N haArachis pintoi cv. Amarillo). The excreta types were dung (1.6 kg/ treatment) and urine (1.0 L/ treatment) from heifers (353.1 ± 24.1 kg BW) grazing in the pastures. Static chambers were used to evaluate N2O emissions, which were determined by gas chromatography (electron capture detector), and were integrated over time, to calculate the cumulative emissions and the amount of nitrogen lost as N2O. Posteriorly, ANOVA was performed and the Tukey’s test was ran to determine differences among means. Dung emissions of N2O totaled 1151, 579 and 245 µg N-N2O mP = 0.0052). Urine emissions of N2O were 273, 347 and 275 µg N-N2O m2O emission factor differed between excreta type and was 2.2 times greater for dung than for urine (P = 0.038). For dung, the emission factor (EF) varied from 0.15 to 0.83% N-applied and for urine ranged 0.16% N-applied emitted as N2O. The greatest emissions were observed for FERT. Excreta affected N2O emissions, and in all cases, it was much lower than IPCC default Tier 1 emission factor.
Ammonia (NH3) is a large source of environmental contamination from nitrogen usage. The objective... more Ammonia (NH3) is a large source of environmental contamination from nitrogen usage. The objective of this study was to evaluate NH3 losses from urine and dung of cattle grazed in Marandu-grass pastures (Brachiaria brizantha cv. Marandu) with different sources of nitrogen. The experiment consisted of two factors (pasture management and excreta type) in a randomized complete block design, with 5 replicates. The pastures were: 1) CONTROL: Marandu-grass pastures without nitrogen or legume; 2) FERT: Marandu-grass pastures fertilized with nitrogen (150 kg N ha-1 year-1); 3) MIXED: Marandu-grass pastures intercropped with Pinto peanut (Arachis pintoi cv. Amarillo). The excreta types were dung (1.6 kg/ treatment) and urine (1.0 L/ treatment) from heifers (353.1 ± 24.1 kg BW) grazing in the pastures. Ammonia volatilization was evaluated using semi-opened free static chamber and nitrogen determination by steam distillation. Sampling were performed on 1, 3, 5, 9, 14 and 21 d after treatments being applied to the area. ANOVA was performed for total ammonia volatilized; when differences were observed among means, they were compared using the LSD test. For dung, NH3 losses differed among pasture treatments (P = 0.046). Volatilization losses was greater for FERT pastures (1.04% of applied N) compared with CONTROL (0.83% of applied N) and MIXED (0.81% of applied N) pastures. No differences were observed for urine among treatments for FERT (3.69 of applied N), MIXED (3.63 of applied N) and CONTROL (2.78 of applied N). The NH3 emission factor differed between excreta type (P &lt; 0.0001). Urine averaged 3.40% and dung 0.89% of volatilized N-applied. Urine was the main source of ammonia volatilization, and all estimates of volatilization losses were among the lowest reported in the literature.
Pré-inoculação de sementes de Vigna unguiculata (L) Walp. com inoculante polimérico no Centro-Oes... more Pré-inoculação de sementes de Vigna unguiculata (L) Walp. com inoculante polimérico no Centro-Oeste Pre-inoculation of seed the Vigna unguiculata (L) Walp. with
Mircen Journal of Applied Microbiology and Biotechnology, 1987
... experienced. The distillates are titrated against a sulphuric acid solution (0.05-0.25 N), th... more ... experienced. The distillates are titrated against a sulphuric acid solution (0.05-0.25 N), this acid being standardized by titration against a solution of tris (hydroxymethyl) methylamine (THAM) as suggested by Keeney &amp; Nelson (1982). ...
Soil N 2 O fluxes are frequently assessed by the use of static chambers with a single daily sampl... more Soil N 2 O fluxes are frequently assessed by the use of static chambers with a single daily sampling. In this study, two experiments were conducted in two contrasting climatic locations, one in Edinburgh, UK, and the other at Seropédica, Rio de Janeiro State, Brazil. Soil N 2 O fluxes were monitored every 6 h for 30 days during the summer in Edinburgh by the use of an automatic chamber system, and every 3 h for 5 days at Seropédica, using a manually-sampled static chamber. Air and soil temperatures were also measured at the same time as the N 2 O fluxes. The principal driver of N 2 O flux within any diurnal period was found to be soil temperature. Regression analysis showed that, for both places, the evenings (21:00e22:00 h) and mornings (09:00e10:00 h), were the times that the flux best represented the daily mean. The ability to work in daylight make the morning period the preferred one.
In a paper published recently in this Journal a new equation was presented for the calculation of... more In a paper published recently in this Journal a new equation was presented for the calculation of the proportion of plant nitrogen derived from plant-associated biological nitrogen fixation (BNF) using the ‘A-value’ technique. To apply this technique it is assumed that the specific availability (‘A-value’) of soil N is constant regardless of the quantity of added labelled N fertilizer. The
In the estimation of the contribution of biological nitrogen fixation (BNF) to plant nutrition ma... more In the estimation of the contribution of biological nitrogen fixation (BNF) to plant nutrition many authors have compared the estimates derived from the15N-isotope-dilution technique with those derived from the total N-difference technique. In this paper we show that agreement of these two estimates is mathematically inevitable when the recovery of labelled nitrogen (%FUE) by the “N2-fixing” (test) and control plants
Biological nitrogen fixation (BNF) associated with trees and shrubs plays a major role in the fun... more Biological nitrogen fixation (BNF) associated with trees and shrubs plays a major role in the functioning of many ecosystems, from natural woodlands to plantations and agroforestry systems, but it is surprisingly difficult to quantify the amounts of N2 fixed. Some of the problems involved in measuring N2 fixation by woody perennials include: (a) diversity in occurrence, and large plant-to-plant variation
A introducao de leguminosas em pastagens de gramineas, na forma de consorcio, tem sido apresentad... more A introducao de leguminosas em pastagens de gramineas, na forma de consorcio, tem sido apresentada como uma estrategia para repor as quantidades de N que se tornam indisponiveis para as gramineas ao longo dos anos. O efeito positivo desta pratica para o ganho de producao animal e conhecido porem, ainda sao escassos os resultados que demonstrem que a leguminosa tambem favoreca a um aumento da longevidade da pastagem. Neste trabalho, comparou-se uma pastagem de Brachiaria ruziziensis consorciada com Srylosanthes guianensis com outra de B. ruziziensis em monocultura, com base em parâmetros da propria pastagem e de producao animal. Os resultados mostraram que a pastagem consorciada permitiu um maior ganho de peso animal por area e um continuo ganho de peso dos animais durante todo o periodo de avaliacao. A producao de forragem da pastagem consorciada superou em cerca de 4 t/ha a pastagem de graminea durante o periodo avaliado (abril/97 a outubro/97), o que aparentemente foi resultado de...
Resumo A cultura de capim elefante (Pennisetum purpureum Schum.) é altamente eficiente na fixação... more Resumo A cultura de capim elefante (Pennisetum purpureum Schum.) é altamente eficiente na fixação de CO2 (gás carbônico) atmosférico durante o processo de fotossíntese para a produção de biomassa vegetal. Por ser uma espécie de rápido crescimento, a biomassa de capim-...
The existence of large population of ineffective native rhizobia and inconsistent performance of ... more The existence of large population of ineffective native rhizobia and inconsistent performance of exotic strains in Ghanaian soils necessitate the need to identify effective and locally adapted elite strains for enhanced legume-rhizobium symbiosis. This study was designed to test the suitability of two previously selected potential elite Bradyrhizobium strains for use as inoculants on cowpea (Vigna unguiculata L. Walp) and groundnut (Arachis hypogaea L.) in multilocation experiments. Field experiments were set up at 26 locations (12 planted with cowpea and 14 planted with groundnut) in the Northern region of Ghana. Four treatments were applied at each location: inoculation with Bradyrhizobium strains KNUST 1002 and KNUST 1006, a positive nitrogen (+N) control and a negative control (without nitrogen or inoculation) arranged in randomized complete blocks with four replications. The results showed that inoculation with strains KNUST 1002 and KNUST 1006 promoted significant increases in grain yields of both cowpea and groundnut. On average, inoculating cowpea with strains KNUST 1002 and KNUST 1006 resulted in 63 and 52% increases in grain yield when compared to the negative control. Pod yields of groundnut, on the other hand, were significantly (p < 0.05) increased at 57% of the study locations with one or both test strains. Responses to inoculation were, however, highly variable across the different study locations (i.e., significant Treatment × Location Interaction, TLI). A detailed analysis of this significant TLI based on the genotype main effect (G) plus genotype-by-environment (GE) interaction (GGE) biplot analysis revealed that location contributed 71 and 88% of the variation observed in cowpea and groundnut, respectively, and grouped the locations into mega-environments for cowpea. These results demonstrate that native elite Bradyrhizobium strains KNUST 1002 and KNUST 1006 have potential for use as inoculants to increase cowpea and groundnut production in Northern Ghana.
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