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The objectives of this study were to examine the effects of starter N inputs and Bradyrhizobium inoculation on soybean symbiotic N fixation and grain yield under field and greenhouse conditions. The study was conducted in the Wellington and the Habitant dykelands in NS. The treatments consisted of 0, 1.5, 3 and 4.5 g/kg seed rates of inoculant and 0, 10, 20, and 30 kg/ha rates of N fertilizer. Under acidic soil conditions, the inoculated plants showed significant N fixation responses in the Wellington field while saline soil conditions suppressed N fixation in the Habitant field. The soybean grain yield showed an increasing trend with the inoculant rate 4.5 g/kg seed. The starter N fertilizer did not facilitate the soybean grain yield in the dykelands. Under controlled environment conditions, inoculant rate 3 g/kg seed alone produced the same amount of yield as 1.5 and 4.5 g/kg seed rates with N fertilizer.

Pulse crops included in a crop rotation can reduce nitrogen (N) requirements via biological N2 fixation (BNF) and provide greater carbon (C) inputs to soil than non-pulse crops in rotation. The goal of this research was to estimate the BNF and C input to soil by various pulse crops (chickpea, lentil and field pea) grown in rotation with pulse crops and non-pulse crops. Soil cores from three crop rotations (chickpea-wheat, lentil-wheat and pea-wheat) were collected from Swift Current, SK. Additional soil cores from two rotations (canola-wheat and wheat-canola) were extracted from a field used for commercial cropping in Central Butte, SK. The 15N dilution method and continuous labelling with depleted 13CO2 were used to estimate BNF and 13C input to soil by pulse crops grown in a greenhouse. The continuous labelling with depleted 13CO2 was effective in depleting 13C in plants. The movement of 13C from plant to soil C pools via rhizodeposition was also observed. However, an accurate amount of 13C transferred was not measurable. Different pulse crop performed differently in rotation. Pea had the greatest amount of BNF and produced the most residue-C (pods, stems, leaves and roots) compared to chickpea and lentil. The crop grown in the first year of the three-year rotation also influenced the pulse crops grown in the third year of the rotation. Cropping the same first year and third year pulse crop in rotation (chickpea-wheat-chickpea and lentil-wheat-lentil) performed better than growing different first year and third year pulse crops in rotation (pea-wheat-chickpea and pea-wheat-lentil). Pulse crops grown immediately after wheat yielded better and fixed more N than those after canola. Growing a pulse crop after canola is not recommended in this soil zone.

Orientador: Orivaldo Arf / Coorientador: Aguinaldo José Freitas Leal / Banca: Salatier Buzetti / Banca: Mario Miyazawa / Banca: Waldo Alejandro Ruben Lara Cabezas / Banca: Gustavo Pavan Mateus / Resumo: A adubação nitrogenada na cultura do milho vem passando por modificações em função do uso de tecnologias tais como a fixação biológica de N e o revestimento dos fertilizantes com polímeros. Este trabalho teve como objetivo avaliar o efeito da inoculação de sementes de com Azospirillum brasilense (com e sem inoculação), fontes (Ureia e Ureia revestida com Policote®) e doses de N em cobertura (0, 45, 90, 135 e 180 kg ha-1) na cultura do milho, em esquema fatorial 2x2x5, com 4 repetições. Foram conduzidos experimentos em duas épocas de semeadura (primeira e segunda safra) e em duas regiões do cerrado brasileiro, Chapadão do Sul e Selvíria-MS. Avaliaram-se as perdas de N por volatilização, teor de N mineral no solo, características morfológicas, teor de N nas folhas, produtividade de grãos e análise econômica. Conclui-se que a inoculação com Azospirillum brasilense proporcionou resultados inconsistentes, podendo, no entanto, incrementar a produtividade e lucratividade do milho. O pico de perdas de N por volatilização da amônia ocorre nos três primeiros dias; a Ureia revestida com Policote® foi mais eficiente que a Ureia convencional para os cultivos do milho "primeira safra", diminuindo as perdas por volatilização, contudo para o milho "segunda safra" não houve diferenças entre as fontes; o teor de N mineral não foi influenciado pelas fontes de N, e a Ureia revestida com Policote® pode elevar a lucratividade em condições mais favoráveis às mais altas produtividades, e reduzi-la em ambientes menos propícios. As doses de N em cobertura elevaram a produtividade de grãos do milho tanto nos experimentos de milho "primeira safra" quanto de milho "segunda safra"; porém, em relação ao milho "primeira safra", as maiores lucratividades... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nitrogen fertilization in maize has been undergoing changes in function of the use of technologies such as N fixation and fertilizer coating polymer. This work aimed to evaluate the effect of inoculation of seeds with Azospirillum brasilense (with and without inoculation), sources (Urea and Urea coated with Policote ®) and rates of nitrogen at top dressing (0, 45, 90, 135 and 180 kg ha-1) in maize crop, in a 2x2x5 factorial scheme with four replications. Experiments were conducted in two sowing periods ("summer and "off-season ") and in two regions of Brazilian cerrado, Chapadão do Sul and Selvíria-MS (Mato Grosso do Sul State). It was evaluated the N losses by volatilization, mineral N level in the soil, phytotechnical characteristics, leaf N content, grain yield and economic analysis. It was concluded that inoculation with Azospirillum brasilense provided inconsistent results, however, may influence positively the maize crop and the profitability, The peak of N losses by ammonia volatilization occurs in the first three days; the Urea coated with Policote® was more effective than conventional Urea at the "summer corn", reducing losses by volatilization during this period, unlike the "off season corn" that did not verify diferences betwen sources; The mineral N level was not influenced by N sources, and the Urea coated with Policote® can boosting increasing the profitability in more favorable conditions to the higher yields, and reduce it in less prone environments. N rates increased grain yield of maize in both tests "summer corn" as the "off season corn." However, in relation to the "summer corn," the best economic returns rates were at 90 and 135 kg ha-1 for Chapadão do Sul and between 135 and 180 kg ha-1 for Selvíria. As for the "off season corn", economically, the absence of nitrogen, provided the greatest gains in Chapadão do... (Complete abstract click electronic access below) / Doutor

There is a demand for new recommendations for pulse seeding rates that will meet the needs of organic farmers. This study was conducted to determine the impact of seeding rate on N2 fixation and N accumulation in lentil and pea and to examine the impact of different seeding rates of lentil and pea on the productivity and N-uptake (i.e., N benefit) in a subsequent wheat crop.<p> The study was performed between 2005 and 2007. Two sites were selected each year of the two-year experiment on certified organic farms in central Saskatchewan. At each location, lentil (<i>Lens culinaris</i> L.) cultivar CDC Sovereign and field pea (<i>Pisum sativum</i> L.) cultivar CDC Mozart were each seeded at five different rates. Wheat (<i>Triticum aestivum</i> L.) cultivar AC Elsa was sown as a non-fixing reference crop at a plant population density of 250 seeds m-2. In the following year, wheat was sown to assess the effect of the pulse seeding rate treatments on the succeeding crop.<p> The pulse crop seeding rates significantly affected the quantity of N2 fixed of lentil and field pea, although %Ndfa (80 to 88% and 79 to 85% for lentil and pea, respectively) typically was unaffected by seeding rate. Yield parameters of following wheat crop were not affected by the seeding rates of the previous pulses. Typically, N contributions increased with increasing seeding rates of both lentil and pea, but there was no detectable difference in N uptake by the following wheat grown on the both pulse stubble. The different seeding rates of organically grown lentil and field pea have impacts on the amount of N2 fixed and N contribution to the soil. However, the differences in N remaining in the soil at different seeding rates of the pulse crops were not detectable in the following wheat crop and the soil N in the following year.

There is a demand for new recommendations for pulse seeding rates that will meet the needs of organic farmers. This study was conducted to determine the impact of seeding rate on N2 fixation and N accumulation in lentil and pea and to examine the impact of different seeding rates of lentil and pea on the productivity and N-uptake (i.e., N benefit) in a subsequent wheat crop.<p> The study was performed between 2005 and 2007. Two sites were selected each year of the two-year experiment on certified organic farms in central Saskatchewan. At each location, lentil (<i>Lens culinaris</i> L.) cultivar CDC Sovereign and field pea (<i>Pisum sativum</i> L.) cultivar CDC Mozart were each seeded at five different rates. Wheat (<i>Triticum aestivum</i> L.) cultivar AC Elsa was sown as a non-fixing reference crop at a plant population density of 250 seeds m-2. In the following year, wheat was sown to assess the effect of the pulse seeding rate treatments on the succeeding crop.<p> The pulse crop seeding rates significantly affected the quantity of N2 fixed of lentil and field pea, although %Ndfa (80 to 88% and 79 to 85% for lentil and pea, respectively) typically was unaffected by seeding rate. Yield parameters of following wheat crop were not affected by the seeding rates of the previous pulses. Typically, N contributions increased with increasing seeding rates of both lentil and pea, but there was no detectable difference in N uptake by the following wheat grown on the both pulse stubble. The different seeding rates of organically grown lentil and field pea have impacts on the amount of N2 fixed and N contribution to the soil. However, the differences in N remaining in the soil at different seeding rates of the pulse crops were not detectable in the following wheat crop and the soil N in the following year.

Made available in DSpace on 2014-06-11T19:35:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-29Bitstream added on 2014-06-13T21:07:41Z : No. of bitstreams: 1 kaneko_fh_dr_ilha.pdf: 1593338 bytes, checksum: f2f3c19be9dbf0e0a2fd04f94e2f1b78 (MD5) / A adubação nitrogenada na cultura do milho vem passando por modificações em função do uso de tecnologias tais como a fixação biológica de N e o revestimento dos fertilizantes com polímeros. Este trabalho teve como objetivo avaliar o efeito da inoculação de sementes de com Azospirillum brasilense (com e sem inoculação), fontes (Ureia e Ureia revestida com Policote®) e doses de N em cobertura (0, 45, 90, 135 e 180 kg ha-1) na cultura do milho, em esquema fatorial 2x2x5, com 4 repetições. Foram conduzidos experimentos em duas épocas de semeadura (primeira e segunda safra) e em duas regiões do cerrado brasileiro, Chapadão do Sul e Selvíria-MS. Avaliaram-se as perdas de N por volatilização, teor de N mineral no solo, características morfológicas, teor de N nas folhas, produtividade de grãos e análise econômica. Conclui-se que a inoculação com Azospirillum brasilense proporcionou resultados inconsistentes, podendo, no entanto, incrementar a produtividade e lucratividade do milho. O pico de perdas de N por volatilização da amônia ocorre nos três primeiros dias; a Ureia revestida com Policote® foi mais eficiente que a Ureia convencional para os cultivos do milho “primeira safra”, diminuindo as perdas por volatilização, contudo para o milho “segunda safra” não houve diferenças entre as fontes; o teor de N mineral não foi influenciado pelas fontes de N, e a Ureia revestida com Policote® pode elevar a lucratividade em condições mais favoráveis às mais altas produtividades, e reduzi-la em ambientes menos propícios. As doses de N em cobertura elevaram a produtividade de grãos do milho tanto nos experimentos de milho “primeira safra” quanto de milho “segunda safra”; porém, em relação ao milho “primeira safra”, as maiores lucratividades... / Nitrogen fertilization in maize has been undergoing changes in function of the use of technologies such as N fixation and fertilizer coating polymer. This work aimed to evaluate the effect of inoculation of seeds with Azospirillum brasilense (with and without inoculation), sources (Urea and Urea coated with Policote ®) and rates of nitrogen at top dressing (0, 45, 90, 135 and 180 kg ha-1) in maize crop, in a 2x2x5 factorial scheme with four replications. Experiments were conducted in two sowing periods (summer and “off-season ) and in two regions of Brazilian cerrado, Chapadão do Sul and Selvíria-MS (Mato Grosso do Sul State). It was evaluated the N losses by volatilization, mineral N level in the soil, phytotechnical characteristics, leaf N content, grain yield and economic analysis. It was concluded that inoculation with Azospirillum brasilense provided inconsistent results, however, may influence positively the maize crop and the profitability, The peak of N losses by ammonia volatilization occurs in the first three days; the Urea coated with Policote® was more effective than conventional Urea at the summer corn, reducing losses by volatilization during this period, unlike the off season corn that did not verify diferences betwen sources; The mineral N level was not influenced by N sources, and the Urea coated with Policote® can boosting increasing the profitability in more favorable conditions to the higher yields, and reduce it in less prone environments. N rates increased grain yield of maize in both tests summer corn as the off season corn. However, in relation to the summer corn, the best economic returns rates were at 90 and 135 kg ha-1 for Chapadão do Sul and between 135 and 180 kg ha-1 for Selvíria. As for the off season corn, economically, the absence of nitrogen, provided the greatest gains in Chapadão do... (Complete abstract click electronic access below)

MSCAGR (Plant Production) / Department of Plant Production / Chickpea (Cicer arietinum L) is adapted to cool-seasons and its organs are of high nutritive value and serve as cheap sources of protein, especially in developing countries. Chickpea crop is mainly grown for human consumption, animal feed and for medicinal purposes. The introduction and promotion of chickpea to especially small-scale South African crop farmers has multiple objectives including the improvement of soil fertility. Small-scale farmer’s flounder to afford Nfertilizers, coupled with the challenges faced by programmes aimed at assisting them about soil fertility in their cropping fields that are still without enough N concentration to meet N demand. It is therefore important that other alternatives that can help improve the N status of soils be explored. The shoot δ13C is an indicator of WUE in C3 plants. However, shoot-WUE is affected by a variety of factors including genotypes, phosphorus fertilizer application and availability of native or introduced rhizobial bacteria. However, not much is known on whether application of phosphate fertilizer, seed inoculation with rhizobial strain affect the shoot C/N ratio of chickpea genotypes in South Africa. Therefore, field experiments were established at Thohoyandou and Syferkuil in Limpopo to assess the role of phosphorus fertilization and rhizobial inoculation on C assimilation, C/N ratio and shoot-WUE of chickpea genotypes. Field experiments were conducted during winter season in 2016 and 2017 (April to August). Treatments consisted of a factorial combination of two rates of phosphorus fertilizer (0 and 90 kg P ha-1 ), four desi chickpea genotypes (ACC#1, ACC#2, ACC#3 and ACC#5) and two rhizobial inoculation levels (bradyrhizobium strain and without rhizobial strain. In Thohoyandou, ACC#1 showed greater grain yield in 2016 and 2017. Which was associated with more branches and greater plant height. Furthermore, the interaction between genotypes, phosphorus fertilizer and rhizobial inoculation had significant effect on grain yield in 2016. ACC#1, 3 and 5 of chickpea genotypes fixed the most N compared to that of ACC#2. In addition, ACC#5 had the highest soil N-uptake in both seasons followed by ACC#3, while ACC#1 had the least value of soil N-uptake in both seasons. Phosphorus fertilizer application increased the fixation of N by 36.8% (P≤0.01), and similarly in soil N-uptake by difference of 59.9% compared to control in 2016. Furthermore, rhizobial inoculation increased N-fixed in 2016 and soil N-uptake in both seasons. ACC#5 had the highest N fixed at phosphorus-fertilized with bradyrhizobuim across two locations in both seasons. ACC#5 depended more on soil N-uptake than fixing its own N as compared to ACC#1. N fixation differed across seasons; however, ACC#3 had greater N-fixed in both locations. Moreover, chickpea genotype that fixed more N had least δ15N. This finding indicates that N fixation is exhibited by the genotypes that depend less on δ15N, because N2 fixation is inhibited by high soil N concentration or δ15N. Furthermore, ACC#2 and ACC#3 had greater δ13C at Thohoyandou in 2017; chickpea genotypes had significant effect on δ13C at P≤0.05 at Thohoyandou, 2016. The results showed that ACC#1 with phosphorus fertilizer application and no bradyrhizobium strain showed greater δ13C. Also, δ13C increased with a decrease in N-fixed (r=.1000), this indicates that there was a functional relationship between plant WUE and N fixation in chickpea, probably because improved water use in legumes supports N fixation. / NRF

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In southern Brazil is unknown the effect of diazotrophs inoculation in sugarcane (Saccharum officinarum). The evaluation of this practice and the selection of genotypes with high potential for biological N fixation (BNF) are essential for obtaining high yields of sugarcane in Rio Grande do Sul (RS). This study investigated the effect of diazotrophic bacteria inoculation and nitrogen fertilization on growth and productivity of sugarcane genotypes in RS. Two experiments were carried out in field conditions. In the experiment I, conducted in São Francisco de Assis/RS, the RB835089 genotype was grown on a Quartzipsament soil with and no-inoculation under two nitrogen levels (0 and 120 kg N ha-1). In the second experiment, conducted in Jaguari/RS on a Hapludalf, 10 genotypes were evaluated (RB835054, RB855156, RB925211, RB925345, RB986419, RB867515, RB975038, RB945177, RB947625 and RB987935) in three managements: nitrogen fertilization (120 kg N ha-1), without N and diazotrophic bacteria inoculation and control (without N and no-inoculation). In both experiments the diazotrophic bacteria inoculation in stems of genotypes was conducted with Embrapa-Agrobiology inoculant, composed of five diazotrophic strains. The evaluated parameters were: biometric variables, dry matter and total nitrogen accumulation and stems productivity. In the first experiment, inoculation increased growth and N accumulation. The stems productivity of the RB835089 inoculated was similar to the treatment that received nitrogen and was 50% higher than the control. In experiment II, sugarcane productivity ranged from 57 to 118 Mg ha-1. Four genotypes did not respond to fertilization and inoculation. Tillering was the variable most responsive to diazotrophic bacteria inoculation with a direct influence on the stems productivity. The response to inoculation varied among genotypes and was observed in genotypes RB855156, RB945177 and RB947625. These genotypes showed stems productivity that exceeded those of the control treatment, respectively, in 13 (18%), 21 (36%) and 13 (22%) Mg ha-1. The results of this study indicate that diazotrophic bacteria inoculation increases the stems productivity of the cane plant in responsive genotypes to practice, saving of nitrogen fertilizer through BNF. / Na região sul do Brasil é desconhecido o efeito da inoculação de bactérias diazotróficas em cana-de-açúcar (Saccharum officinarum). A avaliação desta prática e a seleção de genótipos com elevado potencial de fixação biológica de N (FBN) é indispensável para obtenção de altos rendimentos de cana no Rio Grande do Sul (RS). O presente trabalho objetivou estudar o efeito da inoculação de bactérias diazotróficas e da adubação nitrogenada sobre o crescimento e a produtividade de genótipos de cana-de-açúcar no RS. Foram realizados dois experimentos de campo. No experimento I, realizado no município de São Francisco de Assis/RS, o genótipo RB835089 foi cultivado em Neossolo Quartzarênico distrófico com e sem inoculação sob dois níveis de adubação nitrogenada (0 e 120 kg ha-1 de N). No experimento II, realizado no município de Jaguari/RS o solo foi um Argissolo Vermelho distrófico arênico, onde foram avaliados 10 genótipos (RB835054, RB855156, RB925211, RB925345, RB986419, RB867515, RB975038, RB945177, RB947625 e RB987935) sob três formas de manejo: com adubação nitrogenada (120 kg de N ha-1), sem N e com inoculação de bactérias diazotróficas e testemunha (sem N e sem inoculação). Nos dois experimentos a inoculação das bactérias diazotróficas nos colmos dos genótipos foi realizada com inoculante da Embrapa-Agrobiologia, composto por cinco estirpes diazotróficas. Foram avaliadas variáveis biométricas de crescimento, massa seca e nitrogênio total acumulado e a produtividade de colmos. No experimento I, a inoculação promoveu aumento no crescimento e no acúmulo de N. O genótipo RB835089 inoculado apresentou produtividade de colmos semelhante ao tratamento que recebeu adubação nitrogenada e superou a testemunha em 50%. No experimento II, a produtividade de cana planta variou de 57 a 118 Mg ha-1. Entre os genótipos avaliados quatro não responderam a adubação e nem a inoculação. O perfilhamento foi a variável mais responsiva a inoculação de bactérias diazotróficas com influência direta na produtividade de colmos. A resposta à inoculação variou entre os genótipos avaliados, sendo observada resposta ao inoculante nos genótipos RB855156, RB945177 e RB947625. Esses genótipos apresentaram produtividade de colmos que superaram aquelas dos tratamentos testemunhas em 13 (18%), 21 (36%) e 13 (22%) Mg ha-1, respectivamente. Os resultados do presente trabalho indicam que a inoculação de bactérias diazotróficas aumenta a produtividade de colmos de cana planta em genótipos responsivos a essa prática, gerando economia de fertilizante nitrogenado através da FBN.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Researches with the use of inoculants containing bacteria that promote plant growth have been increasing over the years, due to concerns about pollution and high costs of fertilizers. Therefore the objective of this research was to evaluate the forage yield, nutritive value, biological nitrogen fixation (BNF) and the N recovery of Coastcross-1 pastures inoculated with Azospirillum brasilense subjected to cut. The experimental design was randomized blocks with three replications, in a factorial scheme. The factors were the inoculation (without inoculation, inoculated just in the implantation and reinoculated in the second year), levels of nitrogen (0, 100 and 200 kg of N/ha/year) and periods of the years where cuts were made. Forage yield, daily accumulation rate, forage mass, botanical and structural pasture composition, crude protein content, in situ digestibility of organic matter and total digestible nutrients of Coastcross-1 were evaluated during two years. Forage yield without nitrogen fertilizer use in pastures was in the first year 9.1, 11.7 and 11.7 t of DM/ha, and in the second year 8.6, 11.2 and 11.5 t of DM/ha, to inoculation factor, respectively. The average Coastcross-1 contribution in pastures without nitrogen fertilization was 47.9, 58.5 and 62.7%, respectively to the inoculation. There was reduction in Coastcross-1 crude protein content when pasture fertilized with 200 kg of N/ha/year was inoculated. The forage yield and Coastcross-1 contribution rises with the inoculation without nitrogen fertilizers use; and reinoculation is not necessary. To evaluate BNF and the N recovery two treatments were considered for each variable. Evaluations were carried out during one year. To estimate the BNF the treatments were: Coastcross-1 inoculated and Coastcross-1 uninoculated, both without nitrogen fertilization. The biologically fixed nitrogen was 53.8 and 23.0 kg/ha/year for Coastcross-1 inoculated and uninoculated, respectively. In Coastcross-1 without nitrogen fertilization, inoculation elevates the BNF. To estimate the N recovery the treatments were: Coastcross-1 inoculated and Coastcross-1 uninoculated, both fertilized with 100 kg of N/ ha/year. Isotopic recovery of N was 16.5 and 13.7 kg/ha/year for Coastcross-1 inoculated and uninoculated, respectively. Inoculation increases recovery of N in Coastcross-1. The forage yield increase when don’t use nitrogen fertilizers with the inoculation is related to the increase of biological nitrogen fixation. / Pesquisas com o uso de inoculantes contendo bactérias promotoras do crescimento vegetal vêm aumentando ao longo dos anos, devido a preocupações com a poluição e o elevado custo dos fertilizantes. Desta forma, nesta pesquisa objetivou-se avaliar a produção de forragem, o valor nutritivo, a fixação biológica de nitrogênio (FBN) e a recuperação do nitrogênio (N) fertilizante em pastos de Coastcross-1, inoculados com Azospirillum brasilense e submetidos ao regime de corte. O delineamento experimental foi o de blocos ao acaso, com três repetições, em esquema fatorial. Os fatores foram o uso da inoculação (não inoculado, inoculado somente no plantio e reinoculado no segundo ano), doses de N (0, 100 e 200 kg de N/ha/ano) e os períodos do ano em que foram realizados cortes dos pastos. Avaliaram-se no decorrer de dois anos agrícolas a produção de forragem, a taxa de acúmulo de forragem, a massa de forragem, as composições botânica e estrutural do pasto, o teor de proteína bruta, a digestibilidade in situ da matéria orgânica e os nutrientes digestíveis totais da Coastcross-1. As produções de forragem, nos pastos sem aplicação de N, no primeiro ano, foram de 9,1; 11,7 e 11,7 t de MS/ha, e no segundo ano de 8,6; 11,2 e 11,5 t de MS/ha, para o fator inoculação, respectivamente. A participação média da Coastcross-1 nos pastos sem adubação nitrogenada foi de 47,9; 58,5 e 62,7%, respectivamente para o fator inoculação. Houve redução nos teores de proteína bruta da Coastcross-1, quando o pasto adubado com 200 kg de N/ha/ano foi inoculado. Há aumento na produção de forragem e na participação da Coastcross-1 com a inoculação na implantação dos pastos, quando não há aplicação de N, sendo que, a reinoculação não é necessária. Para a avaliação da FBN e da recuperação do N, foram considerados dois tratamentos para cada variável. As coletas foram realizadas durante um ano agrícola. Para a estimativa da FBN os tratamentos foram: a Coastcross-1 inoculada no plantio e a Coastcross-1 não inoculada, ambas sem adubação nitrogenada. O N biologicamente fixado foi de 53,8 e 23,0 kg/ha/ano para Coastcross-1 inoculada e não inoculada, respectivamente. A inoculação eleva a FBN na Coastcross-1 não submetida à adubação nitrogenada. Para a estimativa da recuperação do N aplicado os tratamentos foram: a Coastcross-1 inoculada no plantio e a Coastcross-1 não inoculada, ambas submetidas à adubação com 100 kg de N/ha/ano. A recuperação isotópica de N foi de 16,5 e 13,7 kg/ha/ano para Coastcross-1 inoculada e não inoculada, respectivamente. A inoculação aumenta a recuperação do N fertilizante aplicado pela Coastcross-1. A elevação da produção de forragem em pastos não submetidos à adubação nitrogenada causada pela inoculação tem relação com o aumento da FBN.