Nitrogênio E Potássio Na Fixação Simbiótica De N2 Por Soja Cultivada No Inverno

Novo, Maria do Carmo de Salvo Soares; Tanaka, Roberto Tetsuo; Mascarenhas, H. A. A.; Bortoletto, Nelson; Gallo, Paulo Boller; Pereira, José Carlos Vela Novo Alves; Vargas, A A T

doi:10.1590/s0103-90161999000100021

Cited by 10 publications

(7 citation statements)

References 12 publications

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“…In these environments, N application probably helped to overcome environmental constraints that may have limited the supply of N or its uptake by the crop. Examples of such constraints include poor establishment of the nodule system (Ham et al, 1975, Israel andBurton, 1997), extremely low soil-N at planting (Al-Ithawi et al, 1980, Starling et al, 1998, Taylor et al, 2005, Wood et al, 1993, plant water stress (Chen et al, 1992, Purcell and King, 1996, Reese and Buss, 1992, soil pH problems (Parker and Harris, 1977), low soil temperature (Soares Novo et al, 1999), or an absence of (native) Bradyrhizobium arising from a cropping history without legumes (Bodrero et al, 1985b).…”

Section: Grain Yield Response To N Fertilizationmentioning

confidence: 99%

“…However, antagonism between nitrate concentration in the soil solution and the N 2 fixation process in the nodules is the main constraint the crop faces in terms of increasing N uptake (Streeter, 1988) when no other abiotic stress that reduce BNF activity occurs, e.g. soil moisture (Purcell et al, 2004), soil pH (Parker and Harris, 1977) or soil temperature (Soares Novo et al, 1999). Maximum N 2 fixation occurs between the R3 and R5 stages of soybean development , and any gaps between crop N demand and N supply by N 2 fixation must be met by N uptake from other sources.…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review

Salvagiotti

Cassman

Specht

et al. 2008

Field Crops Research

806

604

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Although relationships among soybean (Glycine max [L.] Merr) seed yield, nitrogen (N) uptake, biological N 2 fixation (BNF), and response to N fertilization have received considerable coverage in the scientific literature, a comprehensive summary and interpretation of these interactions with specific emphasis on high yield environments is lacking. Six hundred and thirty-seven data sets (site-year-treatment combinations) were analyzed from field studies that had examined these variables and had been published in refereed journals from 1966 to 2006. A mean linear increase of 0.013 Mg soybean seed yield per kg increase in N accumulation in above-ground biomass was evident in these data. The lower (maximum N accumulation) and upper (maximum N dilution) boundaries for this relationship had slopes of 0.0064 and 0.0188 Mg grain kg −1 N, respectively. On an average, 50-60% of soybean N demand was met by biological N 2 fixation. In most situations the amount of N fixed was not sufficient to replace N export from the field in harvested seed. The partial N balance (fixed N in above-ground biomass − N in seeds) was negative in 80% of all data sets, with a mean net soil N mining of −40 kg N ha −1 . However, when an average estimated below-ground N contribution of 24% of total plant N was included, the average N balance was close to neutral (−4 kg N ha −1 ). The gap between crop N uptake and N supplied by BNF tended to increase at higher seed yields for which the associated crop N demand is higher. Soybean yield was more likely to respond to N fertilization in high-yield (>4.5 Mg ha −1 ) environments. A negative exponential relationship was observed between N fertilizer rate and N 2 fixation when N was applied on the surface or incorporated in the topmost soil layers. Deep placement of slow-release fertilizer below the nodulation zone, or late N applications during reproductive stages, may be promising alternatives for achieving a yield response to N fertilization in high-yielding environments. The results from many N fertilization studies are often confounded by insufficiently optimized BNF or other management factors that may have precluded achieving BNF-mediated yields near the yield potential ceiling. More studies will be needed to fully understand the extent to which the N requirements of soybean grown at potential yields levels can be met by optimizing BNF alone as opposed to supplementing BNF with applied N. Such optimization will require evaluating new inoculant technologies, greater temporal precision in crop and soil management, and most importantly, detailed measurements of the contributions of soil N, BNF, and the efficiency of fertilizer N uptake throughout the crop cycle. Such information is required to develop more reliable guidelines for managing both BNF and fertilizer N in high-yielding environments, and also to improve soybean simulation models.

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Section: Grain Yield Response To N Fertilizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review

Salvagiotti

Cassman

Specht

et al. 2008

Field Crops Research

806

604

View full text Add to dashboard Cite

show abstract

“…Novo et al (1999) estudando o efeito do potássio sobre a fixação biológica verificaram, com a cultivar de soja IAC-8, aumento na massa seca e no número de nódulos com a adição de 30,4 e 27,9 kg ha -1 de K 2 O, respectivamente. Entretanto, no estudo não foi observada correlação significativa entre os nutrientes presentes na palha das coberturas e o número de nódulos nas plantas de soja.…”

Section: Fonte: Elaboração Dos Autoresunclassified

Produção de soja e germinação carpogênica de Sclerotinia sclerotiorum sob diferentes coberturas de solo

et al. 2013

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ResumoO trabalho teve por objetivo avaliar a influência de diferentes coberturas vegetais de solo sobre a germinação carpogênica de Sclerotinia sclerotiorum e sobre o desenvolvimento e rendimento da cultura da soja. Os tratamentos constaram da palhada de braquiária, canola, cártamo, crambe, girassol e nabo forrageiro, mais um controle sem cobertura. As culturas de cobertura foram semeadas em vasos contendo 4,4 dm³ de solo do tipo Latossolo Vermelho Distroférrico. Após 45 dias o material vegetal foi cortado em pedaços de modo a padronizar a quantidade de palha para 2800 kg ha -1 . Posteriormente, sementes de soja foram semeadas e sete dias após a emergência das plântulas foram alocados dois escleródios de S. sclerotiorum por vaso. Em relação à germinação carpogênica, foi analisado o tempo para a germinação dos escleródios e formação dos apotécios, número de estipes e apotécios por escleródio e a porcentagem de apotécios formados. Na cultura da soja foi determinada a altura de plantas no florescimento e na colheita, índice relativo de clorofila, massa seca da parte aérea e de raiz, número de vagens por planta, número de sementes por vagem, rendimento, número de nódulos por planta e a massa seca de nódulos. Com exceção ao cártamo, constatou-se que o uso de cobertura vegetal do solo reduziu a formação de estipes e apotécios de S. sclerotiorum. As coberturas com braquiária, girassol e nabo forrageiro aumentaram em 16, 10 e 6 dias respectivamente o período para a formação do apotécio, porém, somente braquiária reduziu a porcentagem de apotécios formados. A cobertura do solo com palha de girassol prejudicou o desenvolvimento e o rendimento da cultura da soja. Palavras-chave: Glycine max, coberturas vegetais, germinação de escleródios AbstractThe aim of this work was to evaluate the influence of different soil cover crops on the carpogenic germination of Sclerotinia sclerotiorum and the development and yield of soybean. The treatments consisted of mulches of brachiaria, canola, safflower, crambe, sunflower and forage radish mulch, and a control with no cover mulch. The crops were sown in pots containing 4.4 dm³ of soil type Rhodic Acrustox. After 45 days the plant material was cut into pieces in order to standardize the amount of straw to 2800 kg ha -1 . Soybean seeds were sown and seven days after seedling emergence two sclerotia were allocated in each pot. With regard to carpogenic germination, we analyzed the time to germination of sclerotia and formation of apothecia, number of stipes and apothecia per sclerotia and the percentage

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“…Novo et al (1999) verificaram que o processo simbiótico da soja cultivada no inverno ameno, em determinadas regiões do Brasil, apresentou-se limitado, por causa das temperaturas mais baixas, que prejudicaram o pleno funcionamento dos rizóbios. Nesse caso, a aplicação de nitrogênio em cobertura, na forma de ureia, contribuiu positivamente para o incremento de produtividade da soja.…”

Section: Introductionunclassified

Efeito do nitrogênio suplementar sobre os componentes de rendimento da soja em condição de estresse hídrico

et al. 2014

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Effect of additional nitrogen on soybean yield components in water stress conditionNitrogen is the nutrient required in the largest amounts by soybean. Its limitation to the plants can compromise the final yield of the crop. The aim of this study was to evaluate the effect of additional nitrogen on soybean yield components through the use of different sources, doses and times of application. The study was carried out in a crop area in Arroio Grande, RS. The reproductive stages in which the nitrogen was applied were: R1; R3; R5.1; R5.2; R5.3; R5.4; R5.5; R6 and R7, via ammonium nitrate and amidic sources, in the following doses: 0, 30, 60, 90 and 120 kg ha -1 . The variables evaluated were: number of pods, number of grains per pod and thousand grain weight of the lower, middle and upper thirds separately and total, as well as yield. Randomized blocks were performed with three replicates. Data were subjected to variance analysis and regression analysis was applied. The variables that did not show interaction with doses were analyzed by the Tukey's multiple comparison test, at 5% probability. The application of nitrogen in the soybean reproductive stages positively influenced some yield components. However, it did not increase the yield, possibly due to water stress to which the crop was subjected..

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Nitrogênio E Potássio Na Fixação Simbiótica De N2 Por Soja Cultivada No Inverno

Cited by 10 publications

References 12 publications

Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review

Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review

Produção de soja e germinação carpogênica de Sclerotinia sclerotiorum sob diferentes coberturas de solo

Efeito do nitrogênio suplementar sobre os componentes de rendimento da soja em condição de estresse hídrico

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