Does the residual effect of n-fertilization applied on corn phase maintain forage production of the following pasture phase in an integrated crop-livestock system?

Nutrient cycling represents an important nutrient source in the Integrated Crop-Livestock Systems (ICLS). In general, only the crop phase of the ICLS is fertilized, however little is known about this residual effect of nitrogen fertilization from summer crop to succeeding winter pasture. This research aimed to evaluate the forage growth dynamic and botanical composition of a mixed pasture of black oat (Avena strigosa Schreb) and ryegrass (Lolium multiflorum Lam.) affected by two canopy height managements (high and low) and nitrogen fertilization applied to either the summer crop (corn) or winter pasture phase of an ICLS. The experiment was established in 2012 in southern Brazil. Black oat and ryegrass were growing during winter season and corn (Zea mays L.) during summer season, being this paper related to the 2014 pasture period. Treatments were composed by two canopy heights (25 and 10 cm) and two N-Fertilization Times (N-Pasture or N-Corn) of 200 kg of N ha-1. Canopy height was regulated by beef steers grazing through continuous stocking with a variable stocking rate. Forage mass was lower in the 10 cm canopy height on average, however this forage mass was composed by greater proportion of ryegrass leaves and lower proportion of dead material in relation to the treatment with 25 cm canopy height. The N-fertilization applied directly on pasture phase (N-Pasture) increased forage mass, tiller population density, participation of ryegrass and ryegrass leaf proportion in the forage mass. Furthermore, when pasture was fertilized with N, the forage accumulation rate increased about 69%, highlighting that the corn N-fertilization did not present significant effect on forage productivity. The residual effect of corn N-fertilization was not enough to maintain high forage accumulation. Thus, the pasture N-fertilization is fundamental to keep high-productive crop-livestock system

Produção animal e comportamento ingestivo de bovinos em sistema integrado de produção agropecuária

This trial aimed to assess animal performance and production in a mixture pasture of black oat and annual ryegrass in an integrated crop-livestock system by means of a 2x2 factorial experiment replicated in three randomized blocks. The plots consisted of two canopy heights (10 and 25cm) kept by continuous grazing and submitted to two-nitrogen fertilization (NP – nitrogen applied on pasture in autumn time; and NG – nitrogen applied on corn crop in springtime). The total amount of nutrients applied over the year was the same for all treatments. Forage nutritive value, herbage allowance, forage mass, and pasture carrying capacity increased with nitrogen application (urea – 45% N) on pasture, with no effect on animal performance, resulting in higher animal production per area. Lower sward canopy height led to lower forage mass, longer grazing diurnal time, and shorter rumination diurnal time.Este estudo objetiva avaliar, em sistema integrado de produção agropecuária, o desempenho e a produção animal em pastagem de aveia preta e azevém. O delineamento experimental utilizado foi o de blocos ao acaso em esquema fatorial (2x2), com três repetições. Os fatores foram duas alturas do pasto (10 e 25cm) mantidas sob pastejo com lotação contínua e taxa de lotação variável, além de passarem por duas épocas de adubação nitrogenada no sistema (NP – adubação nitrogenada feita na pastagem, no outono e NG – adubação nitrogenada feita na lavoura - cultura de grãos). A quantidade total de nutrientes aplicados por ano foi a mesma para todos os tratamentos. A aplicação do nitrogênio (ureia – 45% N) na pastagem indicou aumento no valor nutritivo, oferta e massa de forragem, assim como na capacidade de suporte, sem alterar o desempenho animal, resultando em maior produção animal por unidade de área. A menor altura de dossel condicionou menor massa de forragem, maior tempo diurno de pastejo e menor tempo diurno de ruminação

Implicações produtivas de pastejo sob alta severidade em azevém anual manejados com lotação intermitente

Grazing management has as one of the main objectives the vigorous regrowth, since the remaining leaf area has a high correlation with the regrowth potential of pastures. Thus, the objective of the present work was to evaluate the effect of high severity punctual interventions (70%) on productive characteristics of Italian ryegrass pastures managed under intermittent stocking method. The experiment was conducted in the experimental area of ​​the Federal Technological University of Paraná. The treatments consisted of four defoliation strategies from a single entry height (20cm): constant severity 40%; severity of 40% with punctual interventions of 70% in the second; severity of 40% with punctual interventions of 70% in the fourth cut; and severities of 40% and 70% interspersed. The treatments were applied in a completely randomized design with three replications, totaling 12 experimental units. It was evaluated: solar radiation interception, forage production and morphogenic characteristics (leaf appearance rate, phyllochron, leaf elongation rate and leaf senescence rate). The pre-defoliation solar radiation interception did not differ between treatments, only in the post-defoliation situation. For morphogenic characteristics, treatments with high defoliation severity presented the highest values. Forage production did not differ between treatments. Within the conditions applied in the present study (i.e. pre-cut height), punctual interventions of high severity (70%) do not affect the productive capacity of Italian ryegrass.O manejo de desfolha possui como um dos principais objetivos o rebrote vigoroso após o rebaixamento, uma vez que a área foliar remanescente possui alta correlação com o potencial de rebrote dos pastos. Desta forma, o objetivo do presente trabalho foi avaliar o efeito de intervenções pontuais de alta severidade (70%) sobre características produtivas de pastos de azevém anual manejados sob desfolhações intermitentes. O experimento foi conduzido na área experimental da Universidade Tecnológica Federal do Paraná. Os tratamentos consistiram de quatro estratégias de desfolha a partir de uma única altura de entrada (20cm): severidade constante de 40%; severidade de 40% com intervenções pontuais de 70% no segundo corte; severidade de 40% com intervenções pontuais de 70% no quarto corte; e severidades de 40% e 70% intercaladas. Os tratamentos foram aplicados em delineamento inteiramente casualizado com três repetições, totalizando 12 unidades experimentais. Foram avaliadas as variáveis de interceptação de radiação solar, produção de forragem e características morfogênicas (taxa de aparecimento foliar, filocrono, taxa de alongamento foliar e taxa de senescência foliar). A interceptação de radiação solar pré desfolha não diferiu entre os tratamentos, apenas na situação pós desfolha. Para as características morfogênicas os tratamentos com alta severidade de desfolha, apresentaram os maiores valores morfogênicos. A produção de forragem não diferiu entre os tratamentos. Dentro das condições aplicadas no presente estudo (i.e. altura pré-corte), intervenções pontuais de alta severidade (70%) não afetam a capacidade produtiva do azevém anual

Silagem de milho colhida com diferentes alturas e adição de inoculante microbiano e enzimático.

Objetivou-se avaliar a qualidade da silagem de milho colhida com diferentes alturas e adição de inoculante microbiano e enzimático. O delineamento experimental utilizado foi inteiramente casualizado, com os tratamentos em esquema fatorial 3 x 2 + 1 (três alturas, com ou sem inoculante e um padrão representado pela forragem verde), utilizando-se seis repetições (silosexperimentais). As alturas de corte avaliadas foram 20, 40 e 60 cm. O teor de matéria seca, pH,condutividade elétrica, atividade de água e perdas de matéria seca não foram alteradas pelas alturas de corte com ou sem inoculante. A forragem verde apresentou maior pH e condutividade elétrica em relação a silagem. A estabilidade aeróbica foi inferior na forragem verde em relação à silagem.Entretanto, a elevação da altura reduziu a estabilidade aeróbica da silagem, que não foi influenciada pela adição de inoculante. A elevação da altura de corte das plantas de milho de 20 para 60 cm reduza estabilidade aeróbica da silagem, não havendo grande impacto da inclusão de aditivo microbiano a base de bactérias homofermentativas e enzimas fibrolíticas sobre o processo fermentativo em silos de laboratório com baixa quantidade de silagem.The objective was to evaluate the quality of corn silage harvested at different heights and with the addition of microbial and enzymatic inoculant. The experimental design used was completely randomized, with treatments in a 3 x 2 + 1 factorial scheme (three heights, with or without inoculant and a pattern represented by green forage), using six replications (experimental silos). The evaluated cutting heights were 20, 40 and 60 cm. Dry matter content, pH, electrical conductivity, water activity and dry matter losses were not affected by cutting heights with or without inoculant. Green forage showed higher pH and electrical conductivity compared to silage. Aerobic stability was lower in green forage compared to silage. However, the height increase reduced the aerobic stability of the silage, which was not influenced by the addition of inoculant. The elevation of the cutting height of the corn plants from 20 to 60 cm reduces the aerobic stability of the silage, with no great impact of the inclusion of a microbial additive based on homofermentative bacteria and fibrolytic enzymes on the fermentation process in laboratory silos with a low amount of silage

Ingestive behavior of Angus yearling steers in natural grassland subjected to fertilization and over sown of temperate species

The objective was to evaluate the ingestive behavior of Angus yearling steers grazing natural grasslands of Southern Brazil, submitted or not to the application of fertilizers: NG= natural grassland; FNG= fertilized natural grassland, and FONG= fertilized natural grassland improved with the over sown of temperate forage species. Three Angus yearling steers and a variable number of put-and-take animals were used per experimental unit, to maintain a forage allowance of 13 kg of dry matter/100 kg of body weight. Ingestive behavior of tester animals was visually assessed in four seasons of the year through instantaneous records of activity every ten minutes during the daytime period. There was no effect of pasture treatments on ingestive behavior. An interaction between seasons and periods of the day was observed for daily grazing and rumination time (P <0.05). The grazing activities were clustered at the beginning and the end of the day in summer, autumn and winter, while in spring it was similar in the 1 st three quarters of the day, with higher activity in the period close to sunset. The animals spent more time grazing in the spring despite the better quality of forage in this season. Regardless of the season, longer residence and grazing time were found in water foci areas. We conclude that grazing time on natural pastures is influenced by forage mass and forage allowance, and bite rate is influenced by the chemical composition of the sward