PDF | The corn crop is one of the most cultivated in the world and of corn crop, in function of foliar Azospirillum brasilense inoculation, associated with nitrogen doses. capacidade de expansão do grão em milho-pipoca. Inoculação de Azospirillum brasilense e doses de nitrogênio em milho para In this context, the use of bacteria of the genus Azospirillum brasilense appears. inoculation with Rhizobium tropici in the absence of N fertilization was efficient Crescimento do milho em resposta a Azospirillum brasilense.
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Inoculation with Azospirillum, associated with nitrogen fertilization in maize 1. I Agronomist Engineer, Doctor Science. The azosporillum nitrogen fixation is an alternative to supply the nitrogen needed for maize. The objective of this study was to evaluate the development and yield of maize in response to inoculation with Azospirillum associated with nitrogen fertilization.
The experimental design in both experiments was a randomized complete block, azospirkllum four replications, 2x2x2 factorial, with two levels of nitrogen at sowing zero and 20 kg ha -1two levels of inoculum zero and g ha -1 azospirillym two levels of nitrogen in topdressing zero and kg ha There was evaluated the height of ear insertion, total plant height, leaf N content, shoot dry biomass and grain yield.
The height of ear insertion and total plant height were not influenced by the factors under study. Nitrogen fertilization at sowing increased the leaf N content, causing the opposite effect when combined with inoculation. Inoculation with Azospirillum in the absence of nitrogen, provide productivity increases of Maize Zea mays L. Therefore, biological nitrogen fixation is an alternative to supply part of the nitrogen needed for maize culture.
Inoculation of Azospirillum spp. Several authors have reported the positive effects of the interaction between Azospirillum spp. There is also a wide variety of results in the literature regarding the relationship between inoculation azospirillym nitrogen fertilization. Barros Neto azpspirillum, when working with maize subjected to nitrogen fertilization levels and kg ha -1 of N and inoculation of product based on A.
Inoculation with Azospirillum, associated with nitrogen fertilization in maize
In the same way, Quadros have found increases of up to kg ha -1 on the yield of dry weight of maize shoots, when seeds were inoculated with A. Further studies on the interaction of nitrogen fertilization and its influence on the development of maize culture under inoculation with Azospirillum spp. Thus, the objective of this work was to evaluate the development and yield of maize in response to inoculation with Azospirillum spp.
Two experiments were conducted in the field on the summer harvest.
The application of nitrogen at sowing was made in furrow, and at topdressing, there was a broadcasting application at szospirillum days after plant emergence, at which time the plants had leaves. Fertilization with phosphorus and potassium was carried out in the planting furrow according to the chemical analysis of soils. Each experimental plot consisted of four rows spaced by 0. To obtain the usable area, the two side lines and 0.
The parameters assessed included: In the assessment of ear insertion height and plant total height on the plot usable area, azospiriloum were taken from the soil surface to the insertion of the ear and by the end of the stalk, respectively.
In order to do so, a measurement ruler was used for surveying. Leaf N content was determined using the method described by Tedesco et al. Biomass was determined in leaves, stalks milno ears collected from a linear meter of each plot.
Based on the mean moisture content of the sample, the dry biomass produced in each plot was calculated, then extrapolating to kg ha To estimate the grain yield of the culture, all ears from the usable area of each plot were collected, and then threshing azospkrillum performed with the aid of a manual thresher.
Plant height and ear insertion height were not modified by N fertilization and inoculation at both sites Table 2which can be attributed to genetic characteristics of each hybrid, a result also found by Azospriillum et azosiprillum.
The shoot dry biomass was significantly influenced by the interactions between nitrogen topdressing fertilization and inoculation, as well as between nitrogen fertilization of base and topdressing Table 2. It was found that, both for shoot dry biomass and for yield, the inoculation with Azospirillum spp.
It can also be noted on Table 3 azos;irillum without the application of nitrogen topdressing fertilization, seed inoculation with Azospirillum significantly increased the milh of shoot dry biomass in These results exceed those obtained by Cavallet et al. Despite the increase provided by the inoculation, yield values obtained in this experiment were lower than the productivity of hybrid BR which is kg ha -1 for a population of 55, plants per hectare.
Increases in the production of shoot dry biomass and yield provided by inoculation in this study could be attributed to the stimulus that A. In the early studies on the associations between plants and Azospirillum spp.
Such changes in the root system are related to the production of growth enhancing substances by bacteria, since plant growth regulators phytohormonesmainly the indole acetic acid IAAexcreted by Azospirillum spp.
For the experiment carried out in Cascavel, there was significant interaction among inoculation, Azospirrillum application at sowing and in topdressing for the variables yield, shoot dry biomass and leaf N content Table 2.
Results for such interactions are shown in Table 5. As for productivity, it can be noted that, when inoculation with Azospirillum spp. Quadrosin an experiment under tillage with azospiriillum intent to assess the inoculation of maize genotypes with Azospirillum spp. Dalla Santa et al. It is observed that in the absence of nitrogen application in sowing the inoculation of Azospirillum spp. Despite this increase in relation to control, the yield values obtained in this experiment are inferior to kg ha -1 azospirillym for the hybrid AG YG for a population of 55 to 60 thousand plants per hectare.
Nitrogen topdressing fertilization, associated with inoculation, has reduced productivity and shoot dry biomass production Table 5. These results agree with those obtained me Quadroson the other hand, Barros Neto found that the variation of the amount of nitrogen applied in topdressing kg ha -1 and kg ha -1 had no effect on maize yield, whose seeds were inoculated with pre-commercial product based on Azospirillum brasilense.
In this case, it is possible to consider that the incorporation of milgo amount of nitrogen fertilizer to soil, due to topdressing fertilization, has undermined the effect of inoculation. According to Hartmannthe efficiency of biological fixation in Azospirillum spp. This process of control and regulation of nitrogenase complex activity by modulator environmental factors concentration of assimilated nitrogen and oxygen becomes necessary due to the high demand for energy involved in the process of reducing atmospheric nitrogen N 2 by diazotrophic organisms, some 28 moles of ATP per mole of ammonia produced Baldani et al.
Positive effect of inoculation was obtained in the absence of nitrogen in topdressing, with a higher production of shoot dry biomass and productivity in relation nilho treatment without rm.
However, positive responses jilho not always obtained of increased production as a function of seed inoculation with Azospirillum spp. By the other hand, it is agreed that plant genotype is the key factor to obtain the benefits derived from biological nitrogen fixation, combined with the selection of efficient strains. The application of nitrogen, in topdressing or sowing, has positively influenced shoot dry biomass, as well as productivity, and base nitrogen fertilization has also provided an increase in leaf N content of plants Table 5.
Nilho results highlight the significant effects of nitrogen on the development of maize crop, because nitrogen provides a significant increase in leaf area and in the production of dry matter weight, resulting in greater grain yield Escosteguy et al. Increased leaf N content, found in this study, may have enhanced the effects of nitrogen in plant development, since the formation of grain in maize culture is closely related to the translocation of sugars Crawford et al. On the other hand, the associations between inoculation and nitrogen fertilization, base or topdressing, have caused a reduction in leaf N content.
The contribution of biological nitrogen fixation in grasses or food products, such as maize and wheat, in fertilization programs is an issue that needs further study. In both seasons, the ear insertion height and total plant height were not affected by the factors under study.
In addition, nitrogen topdressing fertilization, associated mikho the use of inoculation, has reduced yield and the shoot dry biomass production. Nitrogen fertilization at sowing has increased leaf N content; however, when complemented by inoculation, it caused a reduction of such a variable. Russian Journal of Plant Physiology, Environmental and physiological advances Canadian Journal of Microbiology, Australian Journal of Plant Physiology, On the economy of plant form and function.
Cambridge, Cambridge University Press.
Hartmann A Ecophysiological aspects of growth and nitrogen fixation in Azospirillum spp. Plant and Soil, Lavras, Universidade Federal de Lavras.
Applied and Environmental Microbiology, miluo Pauletti V Ureia no milho: All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License.
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