Productivity of Urochloa brizantha ‘Marandu’ influenced by strategic rest periods and nitrogen levels

Abstract

The effects of two strategic rest periods and associated nitrogen levels on the agronomic and productive characteristics of Urochloa brizantha 'Marandu' were evaluated. The trial was conducted in a completely randomized 4 × 2 split-plot design, with four blocks. The treatments consisted of associations between two rest periods and four nitrogen levels. The rest periods included one at the end of 28 days (RP 28days ) and another when the canopy height was 40 cm (RP 40cm ) and nitrogen levels of 0, 150, 300, and 450 kg N ha -1 year -1 was applied as ammonium sulfate. The following variables were evaluated: rest period (RP) per cycle, total dry matter (TDM), dry matter (kg ha -1 ) and proportion (%) of leaf blade (LB), stem, and senescent material (SM), tiller mass, forage density, leaf area index, height, leaf:stem ratio, and crop growth rate (CGR). The variables height, TDM, LB dry matter, stem dry matter, CGR, and forage density exhibited a linear relationship with RP 28days and a quadratic relationship with RP 40cm with increasing N levels. The proportions of LB and stem had linear relationships with N levels for RP 28days and RP 40cm . The leaf:stem ratio was affected by increasing N levels and it fit the quadratic model for both rest strategies. The SM proportion had a quadratic relationship only with RP 28days . The tiller mass had a linear relationship with RP 28days , whereas SM dry matter showed a linear relationship for RP 40cm . The use of the RP 40cm reduced the period needed to begin a new grazing cycle. The level of 450 kg N ha -1 is recommended for RP 28days and levels between 380 to 400 kg N ha -1 provided better results for RP 40cm .apresentaram comportamento linear para PD 28dias e quadrático para o PD 40cm com crescentes doses de N. As proporções de LF e colmo apresentaram comportamento linear com as doses de N para PD 28dias e PD 40cm . A relação folha:colmo apresentou efeito com as doses de N, se enquadrando no modelo quadrático para ambos as formas de período de descanso. A proporção de MM apresentou comportamento quadrático somente no PD 28dias . A massa por perfilho apresentou efeito linear para o PD 28dias , enquanto a massa seca de MM apresentou efeito linear para o PD 40cm . O uso do PD 40cm permitiu reduzir o tempo de espera para o aproveitamento da forragem nas parcelas. A dose de 450 kg de N ha -1 é recomendada para o PD 28dias e doses entre 380 a 400 kg de N ha -1 permitiram melhores resultados para PD 40cm . Palavras-chave: Frequência de pastejo. Intervalo de pastejo. Pastejo rotativo.

Recuperação de pastagem de braquiária marandu com aplicação de nitrogênio e enxofre

“…A Urochloa brizantha cv Marandu provinda do continente africano, foi introduzida no Brasil em 1967 (Rodrigues et al, 2017). É a cultivar mais plantada no Brasil, possui alta adaptabilidade ao solo e condições climáticas do cerrado brasileiro, alta produtividade de massa seca, adaptabilidade a solos de média e alta fertilidade, persistente e tolerante ao ataque de cigarrinha (Deois spp.)…”

“…É a cultivar mais plantada no Brasil, possui alta adaptabilidade ao solo e condições climáticas do cerrado brasileiro, alta produtividade de massa seca, adaptabilidade a solos de média e alta fertilidade, persistente e tolerante ao ataque de cigarrinha (Deois spp.) (Marchi et al, 2017;Rodrigues et al, 2017;Leite et al, 2019).…”

“…Incremento de 4762 kg ha -1 de MS e 6600 kg ha -1 de MS, respectivamente Domingues et al (2021). usando Urochloa brizantha BRS Paiaguás para avaliar o efeito da fertilização com N (0, 75, 150, 300 e 600 kg ha -1 de N, na forma de sulfato de amônio) nas características produtivas e nutricionais, verificaram as máximas produtividades obtidas de 21.225 e 13.710 kg ha -1 ano -1 de MS para o primeiro e segundo ciclo, respectivamente Rodrigues et al (2017). avaliando o efeito de duas formas de período de descanso (28 dias e altura de 40 cm) combinado com doses de nitrogênio (0, 150, 300 e 450 kg ha -1…”

Forage performance and cattle production as a function of the seasonality of a Brazilian tropical region

“…Marandu is the most expressive forage in Brazil, with 50 million hectares of cultivated area (Leite et al, 2018). This cultivar presents high forage yield and good adaptation to soils and tropical climatic conditions (Rodrigues, Santos, Silveira Junior, & Santos, 2017). Brazilian pastures are also composed of other species of the genus Urochloa (U. decumbens, U. humidicola, U. brizantha cv.…”

Concentration and moment of niacin application on Urochloa brizantha in relation to nitrogen fertilization

“…As with other species of forage grasses, those belonging to the Urochloa genus are highly responsive to nitrogen fertilization, not only in terms of productivity but also with a direct relationship with the bromatological quality of the plants and the way of grazing management (RODRIGUES et al 2017, TEIXEIRA et al 2018. However, the participation of nitrogen as an indispensable input in animal protein production results in need for investments to purchase this nutrient, and, mainly in intensive production systems, these investments can result in large part of the total production costs (COSTA et al 2015).…”