ABSTRACT. The BRSMG Uai common bean cultivar (Phaseolus vulgaris L.) unites traits required by producers, such as high yield and upright stands, the latter of which is considerably improved in relation to previously released cultivars such as BRSMG Madrepérola and Pérola. However, the potential of the cultivar to form symbiotic relationships with rhizobia to fix N2 has not yet been assessed. Here, field experiments were conducted to assess the efficiency of biological nitrogen fixation (BNF) in the cultivar, and to compare this to the efficiencies of other genetic materials widely grown throughout Brazil (BRSMG Madrepérola and Pérola). Experiments were conducted on two Oxisols in Minas Gerais State, Brazil (one during the dry season in the south, and the other during the winter season in the Alto-Paranaíba region), under a no-tillage system over maize stover. A randomized block experimental design was implemented in a 3 × 3 factorial arrangement with four replicates. Individual and combined Analysis of Variance were performed and the data were normalized. Homogeneity of the residual mean squares was observed. Significant effects of factors were identified by Scott-Knott tests and F tests. The BRSMG Uai cultivar responded to inoculation with the rhizobial strain CIAT 899, with yields similar to those achieved upon fertilization with 80 kg ha-1 of N-urea and to the yields of the BRSMG Madrepérola and Pérola cultivars inoculated with the same rhizobial strain. In terms of commercial use, this cultivar may be successful under either of the management practices adopted for N supply, and from the perspective of plant breeding, it has potential for inclusion in breeding programs directed toward improving BNF.

ABSTRACT Studies in the Amazon indicate a wide diversity of rhizobia with the ability for biological nitrogen fixation (BNF), which could expand the number of strains approved for cowpea. Thus, the aim of this field study was to evaluate the agronomic performance in cowpea of the several strains isolated from the soils of the Brazilian states Acre and Rondônia, and to compare them withstrains approved by the Ministry of Agriculture (MAPA) and withnon-inoculated controls (without and with mineral nitrogen fertilizer). The inoculants performed well. Though less effective than the other strains, the UFLA 03-36 strain also was prominent with respect to grain yield. Because of the positive response of the UFLA 03-129 strain, which led to yield increases greater than the obtained from the control without inoculation plus mineral-N, it can be recommended as an inoculum for cowpea. Further investigations should be carried out to obtain MAPA’s approval for their use. Other experiments involving this strain and several cultivars are being carried out on other types of soil and environmental conditions of the state of Minas Gerais.

ABSTRACT Although the use of inoculants containing rhizobia is encouraged, there are no official recommendations for inoculation of snap bean. In this respect, the aim of this study was to evaluate the agronomic performance of Rhizobium strains in symbiosis with snap bean cultivars with different growth habits and crop cycles. The experiment was carried out in pots with soil in a greenhouse in the spring-summer season in Lavras, state of Minas Gerais, Brazil. A completely randomized experimental design was used, with 4 replications, in a 4 × 7 factorial arrangement involving four snap bean cultivars and seven treatments – five strains of Rhizobium (UFLA 02-100, UFLA 02-127, UFLA 04-173, CIAT 899, and PRF 81), plus two controls without inoculation (with and without 500 mg N-NH4NO3∙dm–3). We conclude that: i) while genetic differences were observed among cultivars with respect to nodulating capacity, in all cases significant benefits were observed from BNF inoculation and ii) inoculation with selected strains of Rhizobium, as well as fertilization with mineral N, favors plant growtht, snap bean yields, and accumulation of N in the pods and, therefore, can fully substitute nitrogen fertilization in snap bean grown under protected cultivation.

Resumo: O objetivo deste trabalho foi avaliar a viabilidade da inoculação líquida de Rhizobium etli no sulco de semeadura e certificar a eficiência da estirpe UFLA 02-100 como inoculante potencial para o feijoeiro-comum (Phaseolus vulgaris). Os tratamentos consistiram de três doses do inoculante líquido aplicadas aos sulcos e uma dose aplicada às sementes de feijão-comum, além de dois controles sem inoculação. O inoculante continha 109células de Rhizobium etli mL-1. Independentemente do método de aplicação, a produtividade obtida com a inoculação foi equivalente à da aplicação de N da ureia, mas a aplicação ao sulco, com 0,6 L ha-1, é mais vantajosa pela praticidade operacional e redução de custos.

Abstract: The objective of this work was to evaluate the viability of liquid medium inoculation of Rhizobium etli in the planting furrow and to certify the efficiency of its strain UFLA 02-100 as a potential inoculant for common bean (Phaseolus vulgaris). The treatments consisted of three application rates of liquid inoculant applied in the planting furrows or in common bean seed, besides two controls without inoculation. The inoculant contained 109 cells of Rhizobium etli mL-1. Regardless of the application method, the yield obtained with the inoculation was equivalent to that of N from urea; however, the application in the furrows, at 0.6 L ha-1, is more advantageous due to the operational practicality and reduced costs.

Symbiosis of common bean with nitrogen-fixing bacteria can lead to a reduction in production costs and in environmental impacts. Considering the diversity of soils and climates, it is important to validate bacterial strains under different conditions to consolidate their recommendation as inoculants. Studies concerning the economic viability of Rhizobium inoculation in common bean are few, but they could assist in choosing the strain to be adopted. The aim of this study was to evaluate the performance of Rhizobium strains isolated from acid soils from the Amazon inoculated in seeds of the BRSMG Madrepérola cultivar and to evaluate the economic viability of their use in the field. Four field experiments were conducted in the state of Minas Gerais, Brazil. A randomized block experimental design was used with four replications and seven treatments: inoculation with the strains CIAT 899 (Rhizobium tropici), UFLA 02-100 (R. etli), UFLA 02-68 (R. etli bv. mimosae), UFLA 02-127 (R. leguminosarum bv. phaseoli), and UFLA 04-173 (R. miluonense),plus two controls, one without inoculation + mineral nitrogen (N-urea) at a rate of 80 kg N ha-1 and another without inoculation and without mineral N. The strain CIAT 899 is already recommended for the manufacture of a commercial inoculant, and the others, collected in the Amazon Forest, have proven to be highly effective in biological nitrogen fixation. Symbiosis of common bean with all the strains evaluated leads to satisfactory yields, with reduction in the application rate of mineral nitrogen and in environmental impacts and, consequently, reduction in economic costs, with higher profitability.

RESUMO Para maximizar a contribuição da fixação biológica de nitrogênio no feijoeiro-comum é necessária a utilização de estirpes de bactérias mais adaptadas, competitivas e eficientes no processo simbiótico. Nesse sentido, objetivou-se avaliar, em um Argissolo Vermelho Distrófico típico do município de Formiga-MG, a eficiência agronômica (EA) de três estirpes isoladas de solos ácidos e com alto teor de Al da Amazônia e comparar suas EA à da estirpe referência CIAT 899T e à de dois controles sem inoculação (um sem e outro com 80 kg ha-1 of N-ureia). Os resultados indicaram que a inoculação com as estirpes UFLA 02-100 e UFLA 02-127 propicia rendimento de grãos equivalente ao da estirpe referência e ao do controle com N mineral e que por isso, ambas têm potencial para ser recomendadas como inoculantes para o feijoeiro-comum.

ABSTRACT To maximize the contribution of biological nitrogen fixation in common bean, it is necessary to use bacterial strains that are more adapted, competitive, and efficient in the symbiotic process. In this regard, the aim of this study was to evaluate the agronomic efficiency (AE) of three bacterial strains isolated from acid soils with high Al content from the Amazon region in an Argissolo Vermelho Distrófico típico soil (Typic Rhodustults - USDA Classification) from the municipality of Formiga, MG, Brazil. We compared their AE to that of the reference strain CIAT 899T and of two controls without inoculation (one without and another with 80 kg ha-1 of N-urea). The results indicated that inoculation with the strains UFLA 02-100 and UFLA 02-127 provides grain yield equivalent to inoculation with the reference strain and to the control with mineral N. Thus, both have potential for recommendation as inoculants for common bean.

RESUMO. Objetivou-se avaliar os efeitos da aplicação foliar de molibdênio e do emprego de pequena dose de nitrogênio no plantio sobre a produção do feijoeiro quando se utiliza a inoculação das sementes com rizóbio. Foram conduzidos dois experimentos em campo, em delineamento de blocos ao acaso, esquema fatorial (3x2x2) + 1, com três repetições. Os tratamentos foram inoculação (estirpe CIAT 899T, estirpe UFLA 02-100 e ausência de inoculação), aplicação foliar de molibdênio (0 e 80 g ha-1) e de nitrogênio na semeadura (0 e 20 kg ha-1), mais tratamento adicional com N (40 na semeadura e 40 kg ha-1 na cobertura). A aplicação foliar de molibdênio não favoreceu a nodulação, mas seu efeito sobre o rendimento de grãos foi dependente das características químicas do solo, fornecendo maior produtividade em solo de Patos de Minas, com pH mais ácido e maiores teores de fósforo e matéria orgânica. Pequena dose de nitrogênio no plantio não reduziu a nodulação do feijoeiro inoculado com rizóbio, mas pode reduzir a emergência das sementes, com reflexo negativo na produtividade. Os rizóbios nativos proporcionaram nodulação, crescimento vegetal, acúmulo de nitrogênio na parte aérea e rendimento equivalentes aos tratamentos inoculados com as estirpes de rizóbio.

ABSTRACT. The aim of this study was to evaluate the effects of foliar application of molybdenum and small dose of nitrogen at planting on common bean production when using seed inoculation with rhizobia. Two field experiments were conducted, applying a randomized block design and a factorial arrangement (3x2x2) + 1, with three replicates. Treatments consisted of inoculation with Rhizobium spp. (strain CIAT 899T, strain UFLA 02-100, and uninoculated), foliar application of molybdenum (0 and 80 g ha-1), and fertilization with N-urea at planting (0 and 20 kg ha-1), with an additional N treatment of 40 applied at planting and 40 kg ha-1 applied as topdressing. The foliar application of molybdenum did not favor the nodulation, but its effect on yield was dependent on the chemical soil characteristics, providing highest yield in soil at Patos de Minas with pH more acid and with higher phosphorus and organic matter concentrations. Small dose of nitrogen applied at planting did not reduce nodulation of bean inoculated with rhizobia, but it can reduce the seeds emergence, thus negatively affecting yield. The native rhizobia promoted nodulation, the plant growth, shoot N accumulation and yield similar to the treatments that received inoculations of rhizobia strains.

ABSTRACT: Optimization of symbiosis between nitrogen-fixing bacteria and legumes has been extensively studied, seeking agricultural sustainability. To evaluate the symbiotic efficiency of nitrogen-fixing bacterial strains belonging to the Bradyrhizobium genus with pigeon pea (Cajanus cajan (L.) Millsp.) cv. Fava-Larga, experiments were conducted in Leonard jars (axenic conditions), pots with soil, and in the field. Ten strains were tested in Leonard jars, and three strains, in addition to BR 29, were selected according to their ability to promote the growth of pigeon pea, for further tests in pots with different soil types (Inceptsol and Oxisol) and in the field (Oxisol). Treatments were compared with strains BR 2003 and BR 2801 (approved as inoculants for pigeon pea), with a non-inoculated control with mineral N fertilization, and with another non-inoculated control (absolute control) with low mineral N concentration (Leonard jars) or without mineral N fertilization (soil). The efficiency of Bradyrhizobium strains in axenic conditions varies among strains, being higher when pigeon pea cv. Fava-Larga establishes symbiosis with the strains UFLA 03-320, UFLA 03-321, UFLA 04-212, BR 2801, and BR 2003. The soil type influences the symbiotic efficiency of Bradyrhizobium-pigeon pea in soil in the greenhouse, mainly in Inceptsol, in which strains UFLA 04-212, BR 2801, and BR 2003 increased N accumulation in the plant. The strain UFLA 03-320 increased shoot dry matter and N accumulation in the shoot equivalent to the mineral N treatment under field conditions. UFLA 03-320, BR 29, UFLA 03-321, and UFLA 04-212 promoted yields similar to those of the reference strain (BR 2801), and of the mineral N treatment with 70 kg ha-1 urea-N. These results confirm that pigeon pea establishes efficient symbiosis, which provides the N required for its growth. All strains, except for BR 2003, show potential for recommendation as inoculants for grain production. The strain UFLA 03-320 also shows potential for use in green manure crops.

ABSTRACT Management of biological nitrogen fixation in common bean still requires improvement. The objective of this study was to verify the compatibility of nitrogen fertilization with biological N2 fixation to increase common bean yield and profitability. Four field experiments were performed in four municipalities of Minas Gerais, Brazil, during the 2009 and 2010 winter crop season. The 2009 crop experiments were set up under a no-till system and the 2010 crop was conducted using conventional tillage. A randomized block experimental design was used with four replications and seven treatments combining application rates of mineral N (at sowing and/or topdressing) and seed inoculation with Rhizobium tropici strain CIAT899. Inoculation with 20 kg ha-1 N-urea at sowing and seed inoculation does not interfere with nodule dry matter and promotes yield comparable to that observed with 80 kg ha-1 N-urea with economic profitability in both no-till and conventional tillage systems. These results show the possibility of economic savings with respect to N fertilizers, but also a significant ecological contribution by avoiding problems associated with misuse of these fertilizers, such as eutrophication of waterways and denitrification.

Cowpea (Vigna unguiculata) cultivation in northern and northeastern Brazil provides an excellent source of nutrients and carbohydrates for the poor and underprivileged. Production surplus leads to its consumption in other regions of Brazil and also as an export commodity. Its capacity to establish relationships with atmospheric nitrogen-fixing bacteria is crucial to the reduction of production costs and the environmental impact of nitrogen fertilizers. This study assessed the symbiotic efficiency of new strains of symbiotic nitrogen-fixing bacteria with cowpea and their tolerance to pH and aluminum. Twenty-seven strains of bacteria from different soils were evaluated under axenic conditions. These strains were compared to the following inoculant strains: INPA03-11B, UFLA03-84 and BR3267 and two controls that were not inoculated (with and without mineral nitrogen). Six strains and the three strains approved as inoculants were selected to increase the dry weight production of the aerial part (DWAP) and were tested in pots with soil that had a high-density of nitrogen-fixing native rhizobia. In this experiment, three strains (UFLA03-164, UFLA03-153, and UFLA03-154) yielded higher DWAP values. These strains grow at pH levels of 5.0, 6.0, 6.8 and at high aluminum concentration levels, reaching 10(9) CFU mL-1. In particular UFLA03-84, UFLA03-153, and UFLA03-164 tolerate up to 20 mmol c dm-3 of Al+3. Inoculation with rhizobial strains, that had been carefully selected according to their ability to nodulate and fix N2, combined with their ability to compete in soils that are acidic and contain high levels of Al, is a cheaper and more sustainable alternative that can be made available to farmers than mineral fertilizers.

O objetivo deste trabalho foi avaliar a eficiência simbiótica de estirpes de bactérias fixadoras de nitrogênio do gênero Bradyrhizobium com guandu-anão. Os experimentos foram conduzidos em vasos de Leonard, em vasos com solo e em campo. Foram testadas 11 estirpes em vasos de Leonard, e as que apresentaram maior eficiência em promover o crescimento do guandu-anão foram avaliadas em vasos com solo (Latossolo Vermelho-Amarelo e Cambissolo) e em campo (Latossolo Vermelho-Amarelo). Em todos os experimentos, os tratamentos foram comparados a dois controles positivos (estirpes aprovadas como inoculantes para as cultivares de guandu-anão BR 2003 e BR 2801) e a duas testemunhas sem inoculação, uma com alta concentração de N mineral, e a outra, a depender do experimento, sem N mineral (solo) ou com baixa concentração de N (vasos de Leonard). Algumas estirpes proporcionaram crescimento vegetal semelhante ou superior às estirpes-referência e às testemunhas em vaso de Leonard. Em vasos com solo, o tipo de solo influenciou os tratamentos. No campo, não houve diferença entre os tratamentos, e as estirpes nativas promoveram bom crescimento. O guandu-anão é capaz de estabelecer associação simbiótica com bactérias fixadoras de N2, e a estirpe UFLA 03-320 apresenta potencial para ser recomendada para a cultura junto com a estirpe BR 2801.

The objective of this work was to evaluate the symbiotic efficiency of nitrogen-fixing bacterial strains, from the genus Bradyrhizobium, with dwarf pigeon pea. The experiments were carried out in Leonard jars, in pots with soil and in the field. In Leonard jars, 11 strains were tested, and the most effective in promoting pigeon pea growth were evaluated in pots with soil (Oxisol and Cambisol) and in the field (Oxisol). In all experiments, treatments were compared to two positive controls (strains approved as inoculants for pigeon pea cultivars, BR 2003 and BR 2801) and to two controls without inoculation, one with a high concentration of mineral N, and the other, depending on the experiment, without mineral N (soil) or with low N concentration (Leonard jars). Some strains have provided plant growth similar or superior to the reference strains and to the controls in Leonard jars. In the pot experiment with soil, the soil type influenced the treatments. In the field, there was no difference among treatments, and the native strains promoted a good plant growth. Dwarf pigeon pea is able to establish a symbiotic association with nitrogen-fixing bacteria, and the strain UFLA 03-320 has the potential to be recommended for this crop together with the BR 2801 strain.

Objetivou-se avaliar o efeito do fertilizante mineral NPK associado ao resíduo orgânico "cama de frango", sobre as características agronômicas da soja bem como os teores de nutrientes em um Cambissolo. O experimento foi conduzido no município de Itutinga, sul de Minas Gerais, no delineamento em blocos casualizados, com três repetições em esquema de parcela subdividida. A cultivar utilizada no experimento foi a BRS Favorita RR. Os tratamentos aplicados às parcelas foram constituídos por quatro doses de "cama de frango" (0; 3; 6 e 9 Mg ha-1), aplicados em área total. As subparcelas constituíram as cinco doses do fertilizante mineral formulado NPK 04-30-10 (0; 100; 200; 300 e 400 kg ha-1), aplicados ao sulco de semeadura. A adubação com o fertilizante mineral proporciona aumento na altura de planta e de inserção do primeiro legume, número de legumes por planta e na produtividade de grãos da cultura da soja. A adubação com o resíduo orgânico "cama de frango" eleva a altura de planta e de inserção do primeiro legume, massa de 100 grãos, número de legumes por planta e o rendimento de grãos de soja, porém em doses mais elevadas favorece o acamamento das plantas. A utilização da cama de frango é viável em termos agronômicos e econômicos na cultura da soja. A adição de cama de frango eleva os teores de potássio e enxofre no solo.

The objective of this study was to evaluate the effect of mineral fertilizer NPK associated with the organic waste "poultry litter" on the agronomic characteristics of soybean as well as nutrient levels in the Cambisol. The experiment was carried out in Itutinga, southern Minas Gerais state, Brazil, in a randomized blocks experimental design with three replications in split-plot. The cultivar used was BRS Favorita RR. The treatments applied to plots consisted on four doses of "poultry litter" (0; 3; 6 and 9 Mg ha-1), applied in the total area. The subplots were the five doses of mineral fertilizer NPK 04-30-10 (0; 100; 200; 300 and 400 kg ha-1), applied to the groove seeding. Fertilization with mineral fertilizers provides an increase in plant and first pod height, number of pods per plant and yield of soybean. Fertilization with organic waste "poultry litter" increases the plant and first pod height, weight of 100 grains, number of pods per plant and yield of soybean, however at higher doses favors the lodging of plants. The use of poultry litter is viable in agronomic and economic terms in the soybean crop. The addition of poultry litter increases the contents of potassium and sulfur in the soil.

Com o objetivo de avaliar o efeito de épocas de semeadura do híbrido de sorgo silageiro Volumax, foi conduzido um experimento no Campus da Universidade Federal de Lavras, em Lavras/MG, em dois anos agrícolas 2006/07 e 2007/08. O delineamento utilizado foi o de blocos ao caso, com cinco tratamentos e três repetições, compreendendo cinco épocas de semeadura (30 de outubro, 15 e 30 de novembro e 15 e 30 de dezembro). Foram avaliados o rendimento de massa verde, seca e proteína bruta além dos teores de P, Ca, K, Mg e S na forragem. Os resultados obtidos permitiram constatar decréscimos no rendimento de forragem com o atraso na época de semeadura. A semeadura de 30 de dezembro proporcionou menores teores de nutrientes na forragem do sorgo.

To evaluate the effect of sowing dates of hybrid silage sorghum Volumax, an experiment was conducted on the campus of the Universidade Federal de Lavras, Lavras/MG, in two crop years 2006/07 and 2007/08. The design was to block the case, with five treatments and three replicates with five sowing dates (October 30, November 15 and 30 and December 15 and 30). We evaluated the yield of green mass, dry mass and crude protein and levels of P, Ca, K, Mg and S in forage. The results revealed a decline in forage yield with delayed sowing date. The sowing of December 30 provided lower levels of nutrients in forage sorghum.

O objetivo deste trabalho foi avaliar o efeito do pH do meio de cultivo na eficiência simbiótica de estirpes de Rhizobium, em solo com e sem calagem. Foram realizados experimentos em casa de vegetação, com e sem calagem, e no campo, apenas com calagem. O delineamento experimental utilizado foi de blocos ao acaso com quatro repetições, e os tratamentos foram cinco estirpes de Rhizobium (UFLA 02-100, UFLA 02-68, UFLA 04-195, UFLA 04-202 e CIAT 899), cultivadas em meio de cultura 79 com diferentes valores de pH (5,0, 6,0 e 6,9), e testemunhas sem inoculação, com ou sem nitrogênio mineral. Foram avaliados número e massa de matéria seca de nódulos, massa de matéria seca da parte aérea, eficiência relativa, teor e acúmulo de nitrogênio na parte aérea e nos grãos, número de vagens por planta, número de grãos por vagem e rendimento e massa de 100 grãos. O valor de pH ideal para o meio de cultivo variou com as estirpes e com a variável analisada. Os tratamentos que receberam calagem foram superiores aos demais. No campo, independentemente do pH do inoculante, as populações nativas do solo e as estirpes introduzidas promoveram rendimento de grãos semelhante ao da testemunha com 70 kg ha-1 de N e ao da estirpe referência CIAT 899.

The objective of this study was to evaluate the effect of the culture medium pH in the symbiotic effectiveness of Rhizobium strains in soil, with and without liming. Assays were performed in greenhouse, with and without liming, and in the field, with liming. The experimental design was randomized blocks with four replicates, and treatments were five strains (UFLA 02-100, UFLA 02-68, UFLA 04-195, UFLA 04-202 and CIAT 899), grown in a 79 culture medium with different pH values (5.0, 6.0 and 6.9), and two controls without inoculation: with or without mineral nitrogen. Variables analyzed were number and weight of dry nodules, shoot dry matter, relative efficiency, nitrogen content and accumulation in shoots and grains, number of pods per plant, number of grains per pod, and yield and weight of 100 grains. The optimum pH value for the culture medium varied with the strains and the variable analyzed. Treatments with liming were superior to the others. In the field, regardless of the inoculant pH, the native soil populations and the introduced strains promoted grain yields similar to those of the control with 70 kg ha-1 of N and to those of the reference strain CIAT 899.

O objetivo foi avaliar o efeito das palhadas de milheto (Pennisetum typhoides (Burm.) Stapf) e milheto + feijão-de-porco (Canavalia ensiformes (L.) DC.) e diferentes doses de nitrogênio, na nutrição mineral do feijoeiro. O delineamento foi em blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas, em Latossolo Vermelho, em plantio direto. As parcelas foram constituídas pelas palhadas e as subparcelas por um fatorial 2 x 4 + 1, representado por duas doses de N na semeadura (30 e 60 kg ha-1) e quatro em cobertura (0, 40, 80 e 120 kg ha-1), mais um tratamento adicional, correspondente a 30 kg ha-1 de N na semeadura, sem cobertura, com inoculação das sementes com Rhizobium tropici e aplicação foliar de Co e Mo. A palhada de milheto + feijão-de-porco proporcionou maiores teores foliares de N e Mg. A cobertura nitrogenada aumentou o teor do nutriente até a dose de 116 kg ha-1, proporcionando incrementos lineares nos teores de K e S. Para os teores de Mg houve interação tripla. O tratamento adicional aumentou o teor de N sob palhada de milheto, os teores de K e Cu e o rendimento de grãos sob ambas palhadas e reduziu os teores de Ca e Mg, sob palhadas de milheto e milheto + feijão-de-porco, respectivamente. As doses de N em cobertura aumentaram o rendimento de grãos em ambas as doses de base, com maior resposta na de 30 kg ha-1 de N.

This study was carried out to evaluate the effect of straws of millet (Pennisetum typhoides (Burm.) Stapf) and millet plus jack bean (Canavalia ensiformes (L.) DC.) intercropping and nitrogen fertilization levels on bean mineral nutrition in a no-till system. The experiment was carried out in a randomized blocks design and four replications in a split-plot arrangement, with the straws in the plots and nitrogen levels at sowing (30 and 60 kg ha-1) and at topdressing (0, 40, 80 and 120 kg ha-1) as a 2 x 4 + 1 factorial in sub-plots, plus an additional treatment with 30 kg ha-1 at sowing, without topdressing, and seed inoculation with Rhizobium tropici with Co and Mo foliar application. The millet plus jack bean straw provide the highest N and Mg contents. N topdressing levels increased N foliar concentration up to 116 kg ha-1, providing a linear effect in K and S contents and differenced effects on Mg concentration, depending on the N level at sowing and straw combinations. The additional treatment increased the N concentration only in millet straw, K and Cu in two straws, and reduced the Ca and Mg contents, under millet and millet plus jack bean straws, respectively. The topdressing levels increased the grain yield, with the bigger response in 30 kg ha-1 at of N sowing.