Context ​Defoliation management targets applied to forages under the full sun have not yet been properly evaluated for shaded environments such as occur in integrated crop–livestock systems with the presence of trees. Aims This study aimed to determine defoliation targets under full sun and shaded environments for the shade-tolerant perennial summer grass hybrid Axonopus catharinensis (giant missionary grass), widely used in pasture systems of South Brazil and Argentina. Methods Four pre-defoliation canopy heights (15, 25, 35 and 45 cm) and four defoliation severities (20%, 40%, 60% and 80% reduction in pre-defoliation canopy height) were evaluated. Plants were grown in 0.15 m3 wooden boxes filled with sand/vermiculite substrate (1:1 v/v) and irrigated with a complete nutrient solution. An artificial shade structure was made with wooden slats, reducing light intensity by 50% for shaded plants. Key results Herbage accumulation decreased by 54% in shaded plants compared with those under full sun. Regardless of the light environment, the lowest crude protein content (<150 g/kg dry matter) and the highest neutral detergent fibre content (>650 g/kg dry matter) were observed when the defoliation target height was >35 cm. Both shaded and full sun environments showed decreases in tiller density when defoliation severity was >60% of pre-defoliation canopy heights. Conclusions Pre-defoliation canopy heights >35 cm and defoliation severity >60% of pre-defoliation canopy height should be avoided when managing A. catharinensis, regardless of the light environment. Implications Recommended targets may be easily implemented by livestock producers and are similar for full sun and shade environments.

Pastures are of central importance in food production and provide multiple ecosystem services. The objective of this paper was to determine whether the intensification of pasture-based animal production systems, through practices such as fertilization and improved pasture species, has a higher capacity in the short-term (five years) to sequester carbon in the soil compared to (1) natural grassland without anthropogenic interactions, (2) natural grassland fertilized and overseeded with exotic species, and (3) annual pastures with frequent soil disturbance. The study assessed the organic carbon stock (OCS), total organic carbon (TOC), particle size, porosity, and density at different soil strata, as well as the root system and forage production. Forage dry matter (DM) production varied significantly with means ranging from 6615 to 13,000 kg ha–1 year–1 for natural grassland (NG) and permanent pasture (PP), respectively. Improved natural grassland (ING) and NG presented a higher density and root diameter than PP and annual pasture (AP). Forage systems significantly influenced soil porosity and density, with NG and ING showing lower soil densities and higher soil porosities. The OCS (0–100 cm) was similar between NG (270 Mg ha–1), ING (255 Mg ha–1), PP (274 Mg ha–1), and AP systems (256 Mg ha–1). Over a period of five years, the intensification of pasture-based animal production systems did not have a significant impact on OCS in the soils of a Brazilian subtropical highland.

As pastagens cultivadas de inverno são um importante componente dos sistemas pecuários no sul do Brasil, oportunizando a produção de carne e leite a custos competitivos. A qualidade de sementes é fundamental para o estabelecimento de pastos produtivos, com alto potencial e livre de contaminação de patógenos e plantas indesejáveis. O objetivo do trabalho foi avaliar a qualidade de sementes de forrageiras de inverno adquiridas por produtores rurais no Planalto Catarinense, no verão/outono de 2017 e 2019. Foram amostrados 78 lotes de sementes de forrageiras adquiridas no mercado local em 12 municípios da região. Parâmetros de germinação, pureza, outras sementes e material inerte foram analisadas em laboratório de análise de sementes credenciado no Ministério da Agricultura Pecuária e Abastecimento. A maior parte dos lotes de sementes analisadas estão abaixo do que preconiza a legislação vigente. Isto compromete o estabelecimento, produção e rentabilidade dos pecuaristas.

The animal performance on pasture is directly correlated to canopy structure since this influences the herbage consumption. This study was evaluated the effects of four pre-grazing canopy heights (12, 20, 28 and 36 cm) of Andropogon lateralis Ness on herbage intake and feeding behavior of steers in a natural grassland under intermittent stocking management, using the same proportion of defoliation (40% reduction in pre-grazing height, i.e., post-grazing heights of 7.2, 12.0, 16.8 and 21.6 cm). The experiment was conducted on a total area of 14,000 m2, divided into sixteen paddocks of 875 m2. Thirty-two steers were used, divided into uniform pairs according to the live weight (LW) at the start of the experiment (244 ± 23.0 kg). Each paddock was subdivided into three plots of identical area; the first two plots were used for the adaptation period and the third for the assessment period. A randomized block design was used with four replicates and two assessment periods. Herbage mass and neutral detergent fiber content increased linearly (P < 0,001) with the increase of pre-grazing canopy heights. In contrast, was not affected by treatments, with mean values of 75 g/kg of dry matter (DM) in the upper stratum and 83 g/kg of DM in lower stratum. The herbage intake was similar between treatments (P = 0.255), averaging 1.78% LW. Grazing time increased linearly in the upper stratum and decreased linearly in the lower stratum with increasing pre-grazing canopy heights. Total time spent grazing, ruminating, and idling did not differ between treatments, with means of 52.6%, 23.0%, and 24.2%, respectively. Pre-grazing canopy heights treatments, based on the predominant species A. lateralis, did not affect the daily herbage intake of steers.