Common beans are the main source of protein in underdeveloped countries, and nitrogen (N) is one of the nutrients the most limits the productivity of this crop. This study, under field conditions, aimed to: a) determinate through efficiency indices how N is used by 16 cultivars of common beans; and b) classify these cultivars regarding use efficiency and responsivity to N application. The experimental design was in randomized blocks in split-plot scheme, with four replicates. Main plots consisted of 16 cultivars of common beans commercially classified as ‘Carioca type’. Subplots comprised two rates of N: 20 and 120 kg ha-1 applied as top-dressing. The evaluations were number of pods per plant and grains per pod, hundred-grain weight, shoots dry matter at full flowering, straw and grains dry matter at physiological maturity and grain yield. Based on the dry matter and its nutrient contents, the N accumulations were calculated in shoots and grains. The agronomic, physiological, agro-physiological, recovery and use efficiencies of N were calculated. Cultivar BRSMG Uai stands out by agronomic, physiological, recovery and use efficiencies of N. Genotypes BRSMG Uai, BRS FC402, IPR Campos Gerais, IPR Maracanã and TAA Bola Cheia are efficient and responsive to top-dressing N application.

The crop succession and nitrogen splitting fertilization are managements that can affect the common bean technological quality and, consequently, the profitability of producer and the food biological value. The aim of this study was to evaluate whether crop succession and N splitting fertilization promote differences in the technological quality of common bean grains. The experiment was carried out during winter over two agricultural years in southeastern Brazil. A randomized block design was used in a split-plot scheme, with four replications. The plots were composed of three crop successional systems (maize sole, maize + Urochloa ruziziensis, U. ruziziensis sole) and the subplots contained nine combinations of N splitting fertilization at a rate of 90 kg•ha -1 N top-dressing in the phenological stages V 3 , V 4 , and R 5 of the common bean and a control without fertilization. The evaluated variables were: sieve yield greater than or equal to 12 (SY ≥ 12), crude protein content, cooking time, and hydration ratio. Crop succession promotes differences in the technological quality of common bean; however, the N splitting fertilization did not change the technological attributes of grains. The highest technological quality of common bean was obtained after succession with U. ruziziensis sole, generating large size and crude protein content of grain, followed by the succession with maize + U. ruziziensis intercropping, and finally, the succession with maize sole. Therefore, the crop succession is a fundamental factor for obtaining common bean with higher technological quality, affecting the food biological value and the profitability of producers.

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Biomass and nitrogen accumulation in white oat (Avena sativa L.) under water deficit 1 Knowledge on nitrogen absorption rate by crops can indicate important managements, especially the definition of rates of this nutrient and the best time for topdressing application. This study aimed to evaluate and compare the accumulation of biomass and nitrogen in white oat cultivated under severe, moderate and no water deficit. Treatments consisted of levels of irrigation, with four repetitions. The treatments under severe water deficit (L1), moderate deficit (L3) and no deficit (L5) received 11%, 60% and 100% of the water volume evapotranspired by the crop (ETc). For each treatment, six plants were collected in each replicate. After collection, plants were separated into leaves, culm and reproductive structures (panicle + grains). Second and third order regressions were tested to model the behavior of biomass and nitrogen accumulation in white oat leaves, culms, reproductive structures and total over time. The maximum total nitrogen accumulation in white oat plants in the treatments L1, L3 and L5 was 50 kg ha-1 , 163 kg ha-1 and 246 kg ha-1 , respectively. Severe water deficit drastically reduced biomass and nitrogen accumulation in white oat. Severe water deficit causes earlier peak of biomass and nitrogen accumulation, reduces nitrogen accumulation rate and shortens cycle of white oats.

RESUMO – A escolha da espécie de crotalária associada ao adequado espaçamento entrelinhas de milho possibilitao retorno econômico com o cereal e os benefícios dos adubos verdes. Assim, o objetivo desse trabalho foi avaliar ocrescimento e desempenho agronômico do milho, a quantidade e o acúmulo de nitrogênio na palhada provenientesdos sistemas de cultivo de milho exclusivo e consorciado com Crotalaria juncea, Crotalaria spectabilis e Crotalariaochroleuca e a mistura dessas espécies (“mix”). O delineamento experimental foi o de blocos casualizados, emesquemas de parcelas subdivididas, com quatro repetições. As parcelas foram compostas por dois espaçamentosentrelinhas de milho: 0,45 e 0,90 m. As subparcelas foram compostas por cinco sistemas de cultivo: milho exclusivo;milho + C. juncea; milho + C. spectabilis; milho + C. ochroleuca; milho + “mix” (C. juncea, C. spectabilis e C.ochroleuca). O consórcio com a C. juncea reduz a produtividade do cereal. No entanto, sua utilização no “mix” éviável. Os espaçamentos de 0,45 e 0,90 m não influenciam o crescimento e a produtividade do milho, e a palhada dossistemas de cultivo. Os consórcios com crotalárias proporcionam maior quantidade de palhada em comparação aomilho exclusivo, embora o acúmulo de nitrogênio não seja alterado.Palavras-chave: Zea mays L., Crotalaria juncea, Crotalaria spectabilis, Crotalaria ochroleuca, adubos verdes.GROWTH, YIELD AND STRAW OF EXCLUSIVE AND INTERCROPPED MAIZEWITH CROTALARIAS IN DIFFERENT ROW SPACINGSABSTRACT - The choice of the crotalaria species associated to the adequate maize row spacing allows the economicreturn with the cereal and the benefits of the green fertilizers. Thus, the objective of this work was to evaluate thegrowth and agronomic performance of maize, the amount and nitrogen accumulation in the straw from the exclusiveand intercropped systems of maize with Crotalaria juncea, Crotalaria spectabilis and Crotalaria ochroleuca, andthe mixture of these species (“mix”). A randomized complete block design with four replications was used. The plotswere composed of two maize row spacings, 0.45 and 0.90 m. The subplots were constituted of five systems: exclusivemaize; maize + C. juncea; maize + C. spectabilis; maize + C. ochroleuca; maize + “mix” (C. juncea, C. spectabilis andC. ochroleuca). The consortium with C. juncea reduced cereal productivity. However, its use in the “mix” is feasible.Rows spacings of 0.90 and 0.45 m did not affect maize growth and yield, and straw of systems. The consortium withcrotalaria provided more straw compared to exclusive maize, although the N accumulation did not change.Keywords: Zea mays L., Crotalaria juncea, Crotalaria spectabilis, Crotalaria ochroleuca, green manure crops.

No Brasil, existe uma ampla disponibilidade de cultivares de feijoeiro de vários grupos comerciais. Nesse sentido, estudos para avaliar o potencial produtivo dos genótipos são necessários para a indicação das melhores cultivares aos produtores. Objetivou-se avaliar o desempenho agronômico e qualitativo de cultivares de feijoeiro dos grupos comerciais carioca e especial e indicar os melhores genótipos dentro de cada grupo. O experimento de campo foi conduzido na Unesp, Jaboticabal, SP, na safra de inverno de 2017. Foram utilizadas dez cultivares de feijoeiro comum, sendo cinco do grupo comercial carioca: BRS Estilo, BRS MG Majestoso, BRS Ametista, BRS Notável e BRS Cometa e cinco do grupo comercial especial: BRS MG Realce, BRS Embaixador, BRS FC 305, BRS Executivo e BRS Ártico. O delineamento experimental foi o de blocos casualizados, com quatro repetições. Os resultados foram submetidos à análise de variância (Teste F) e as médias comparadas pelo teste de agrupamento de Scott-Knott a 5% de probabilidade. Para as características de desempenho agronômico, a cultivar BRS MG Majestoso se destacou dentro do grupo comercial carioca e as cultivares BRS Embaixador e BRS Executivo dentro do grupo comercial especial. Na qualidade dos grãos, se destacaram as cultivares BRS Estilo no grupo comercial carioca e a BRS Embaixador no grupo comercial especial.

Soil CO 2 emissions (fCO 2 ) in agricultural areas have been widely studied in global climate change research, but its characterization and quantification are restricted to small areas. Because spatial and time variability affect emissions, tools need to be developed to predict fCO 2 for large areas. This study aimed to investigate soil magnetic susceptibility (MS) and its correlation with fCO 2 in an agricultural environment. The experiment was carried out on a Typic Eutrudox located in Guariba-SP, Brazil. Results showed that there was negative spatial correlation between fCO 2 and the magnetic susceptibility of Air Dried Soil (MS ADS ) up to 34.3 m distant. However, the fCO 2 had no significant correlation with MS ADS , magnetic susceptibility of sand (MS SAND ) nor clay (MS CLAY ). However, MS ADS could be a supplemental mean of identifying regions of high fCO 2 potential over large areas.

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