The objective of this study was to determine the effect of Azospirillum brasilense inoculation and different nitrogen (N) rates applied as topdressing on the productivity of a maize crop and the nutritional value of maize silage. Two experiments were conducted in the 2012/2013 and 2013/2014 harvests. Treatments were distributed in a randomized block design in a factorial arrangement, which consisted of two maize hybrids (AS 1572 and Defender) coupled with nitrogen rates (0, 60, 120, 240, and 480 kg ha^-1), inoculated or uninoculated with A. brasilense. Inoculated seeds were treated with the A. brasilense strains Ab-V5 and Ab-V6. Inoculation with A. brasilense showed interaction with the hybrids, agricultural years, and nitrogen rates for the maize plant yield. In the 2012/2013 agricultural year, inoculation increased the AS 1572 hybrid silage yield by 6.16% and, in the 2013/2014 harvest, A. brasilense inoculation produced an increase of 16.15% for the Defender hybrid. Nitrogen fertilization applied at 0, 60, and 120 kg ha^-1 N benefited the plants inoculated with A. brasilense. The statistical equations revealed that N rates between 0 and 184 kg ha^-1 in A. brasilense inoculated plants raised the plant productivity for silage when compared with the control plants. Regarding the nutritional value of the silage, inoculation with A. brasilense increased the ether extract levels and total digestible nutrients and reduced the amount of acid detergent fiber. For all this, positive results with inoculation for silage yield are dependent on nitrogen fertilization rate. Inoculation with A. brasilense can promote changes in the maize silage quality, but with obtained results it is not possible to definitely conclude upon nutritive value of maize silage.

Biological nitrogen fixation and plant hormone synthesis promoted by Azospirillum spp. bacteria play a role in enhancing crop productivity and reducing losses. This may constitute a strategy to enhance crop productivity and reducing losses, thereby increasing nitrogen fertilization efficiency. This research aimed to evaluate the effects of Azospirillum brasilense Ab-V5 and Ab-V6 strain inoculation and nitrogen fertilization on the agronomic characteristics and productivity of two maize hybrids (Zea mays L.) AS 1572 and AG 9030. Experiments were carried out at Santa Maria, RS, Brazil in the 2013/2014 and 2014/2015 growing seasons using a 2 × 2 × 5 factorial arrangement to distribute two maize hybrids, inoculated, or not, with Azospirillum brasilense, and five nitrogen doses (0, 60, 120, 240, and 480 kg ha⁻¹). Kernel yield, mass, and dimensions, as well as kernel number on the cobs, stalk diameter, plant height, ear insertion height, prolificacy, nitrogen use efficiency (NUE), and their correlations were measured. Compared to uninoculated plants, higher kernel yield (p < 0.05) was observed for AS 1572 hybrid when inoculated with A. brasilense, with an increase of 0.978 Mg ha⁻¹ or 10.95%. This effect was primarily due to the higher NUE rate and the increase (p < 0.05) in the number of kernels per cob. The AG 9030 hybrid showed no response to inoculation. A. brasilense inoculation increased the NUE rate of the AS 1572 hybrid in the condition N zero dose at N 60 kg ha⁻¹ dose. Nitrogen fertilization increased crop productivity, notably by raising kernel mass and other productivity components, but reduced the NUE rate. The maximum technical efficiency obtained for the AS 1572 hybrid was of 10.705 Mg ha⁻¹ with a N dose of 342 kg ha⁻¹, whereas the AG 9030 hybrid produced a maximum grain yield of 10.089 Mg ha⁻¹ with a dose of 350 kg ha⁻¹ of N. We conclude that the inoculation with A. brasilense increases NUE, maize grain yield, and agronomic characteristic in the AS 1572 hybrid.

Neste trabalho objetivou-se avaliar a influência de espécies em consórcio com azevém sobre a composição botânica e estrutural e o valor nutritivo dos pastos em um sistema de transição agroecológica. Foi avaliada a cultura do azevém (Lolium multiflorum Lam.) consorciada com aveia-preta (Avena strigosa Schreb.), trevo-branco (Trifolium repens L.) e amendoim-forrageiro (Arachis pintoi Krapov. & Gregory). O delineamento experimental foi o inteiramente casualizado, com três tratamentos e três repetições. O primeiro pastejo foi realizado 21 dias após a emergência das plantas nas pastagens de azevém + aveia-preta e azevém + amendoim-forrageiro e 28 dias após a emergência na pastagem de azevém + trevo-branco. O segundo pastejo na pastagem de azevém + aveia-preta ocorreu 30 dias após o primeiro pastejo, enquanto nas demais pastagens ocorreu 37 dias depois. As taxas de acúmulo de matéria seca (MS) do início do período de exclusão até o pico de produção de MS foram de 77,7; 75,0 e 71,3 kg/ha/dia de MS para as pastagens consorciadas com trevo-branco, amendoim-forrageiro e aveia-preta, respectivamente. A razão folha/colmo até o segundo pastejo foi elevada em todas as pastagens. A redução dos teores de PB conforme os dias de exclusão no pasto de azevém + aveia-preta é menor que nos pastos de azevém consorciado com trevo-branco ou amendoim-forrageiro.

It was evaluated in this work, crop yield, fermentative quality and nutritional value of the silage of cultivars of white (Avena Sativa L.) and black (Avena Strigosa Schreb) oats cut at two development stages. It was used an experimental randomized block design in a 4 x 2 factorial scheme, consisting of four oat cultivars (two cultivars of black oats: Aveia Preta Comum and UTFP 971; and two cultivars of white oats: ER 91156- 1- 2- 1 and SI 98105- b), with four replicates. The cultivars were ensiled at flowering and dough grain stages. Oat cut at dough grain stage, especially genotypes from white oat, allows the obtainment of a more productive and qualitative silage. Cultivar, genotype, and maturation stage affect protein fractioning and oat silage carbohydrates.

This experiment was carried out to evaluate the effects of the row spacing between corn plants on silage quality. Different spacing between corn rows (40, 60, and 80 cm) was used, but the population of plants was maintained around 65,000/ha in all treatments. Analysis of variance was carried out and means were compared by Tukey's test at 5% of probability. A reduction in row spacing provided better spatial distribution of plants, but did not alter morphological composition or dry matter production. The corn with most equidistant spatial distribution (lowest row spacing) showed an increase in lignin concentration, neutral detergent fiber, and total carbohydrates, and showed a decrease in total digestible nutrients when compared with 80 cm row spacing. However, the organic digestibility matter was not affected by the treatments. The content and quality of protein were higher for 80 cm row spacing compared with the other levels; also, protein content was reduced as the spacing between rows became smaller. The only mineral affected was calcium, which had the lowest value at higher levels of spacing. Although differences were detected for many variables, the most appropriate spacing between rows should also take into account economic and practical aspects when choosing the best plant arrangement