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Publication
PRODUÇÃO DE BIOMASSA E EMISSÃO DE GASES DE EFEITO ESTUFA EM PASTAGENS UTILIZADAS POR BOVINOS DE CARNE
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Authors
Abstract(s)
A presente pesquisa teve como objetivo avaliar a produção de biomassa, composição
botânica e qualidade, bem como a emissão de gases de efeito estufa (GEE) em 3 tipos
de pastagem, utilizadas por bovinos da raça Mertolenga. O estudo decorreu em 2024/25
em Portugal, no Pólo de Elvas do Instituto Nacional de Investigação Agrária e Veterinária,
em 3 pastagens com cerca de 3 ha cada, implantadas em 2023/24: pastagem semeada
uma rica em gramíneas (GRA_75), pastagem semeada rica em leguminosas (LEG_75) e
pastagem natural (NAT) utilizada como referência. Foram colhidas amostras de solo
para análise dos teores de matéria orgânica e nutrientes. Entre 20/02/2025 e 18/7/2025,
a produção de biomassa foi monitorada semanalmente com o Rising Plate Meter (RPM).
Em 28/04/2025 foram colhidas 4 amostras de 0,25 m2 por tratamento para avaliação da
composição botânica. As emissões entéricas de GEE foram estimadas com equipamento
GreenFeed®. Os resultados mostraram que o solo sob pastagem natural apresentou
maior teor de matéria orgânica e de micronutrientes como Fe, Mn, Cu e Zn, enquanto
as pastagens cultivadas apresentaram maior teor de P e Mg. O LEG _75, destacou-se
maiores valores de PB (9,2%), menor teor de fibras e maior digestibilidade (50,9%). Não
se verificaram diferenças significativas na composição botânica, sendo esta dominada por
gramíneas em todos os tratamentos. O trevo subterrâneo foi a espécie semeada com
maior representatividade. A avaliação das emissões entéricas foi limitada pela baixa
adesão dos animais ao GreenFeed®, provavelmente devido ao seu “temperamento
nervoso”, mas também ao curto período experimental e à temperatura ambiente muito
elevada. Concluiu-se que a pastagem natural contribuiu para a acumulação fertilidade do
solo, enquanto a pastagens cultivadas sobretudo as ricas em leguminosas, elevaram a
qualidade nutricional da forragem. Sugere-se que estudos futuros utilizem animais mais
dóceis e em maior número, num período do ano com temperaturas mais amenas.
This research aimed to evaluate biomass production, botanical composition and quality, as well as greenhouse gas (GHG) emissions in three types of pasture used by Mertolenga cattle. The study took place in 2024/25 in Portugal, at the INIAV Elvas, in three pastures of approximately 3 ha each, established in 2023/24: a sown pasture rich in grasses (GRA_75), a sown pasture rich in legumes (LEG_75), and a natural pasture (NAT) used as a reference. Soil samples were collected for analysis of organic matter and nutrient contents. Between February 20, 2025, and July 18, 2025, biomass production was monitored weekly with a Rising Plate Meter (RPM). On April 28, 2025, four 0.25 m2 samples were collected per treatment to evaluate botanical composition. Enteric GHG emissions were estimated with GreenFeed® equipment. The results showed that the soil under natural pasture had higher organic matter and micronutrient contents such as Fe, Mn, Cu, and Zn, while cultivated pasture had higher P and Mg contents. LEG _75 had higher CP values (9.2%), lower fiber content, and higher digestibility (50.9%). No significant differences were observed in botanical composition, which was dominated by grasses in all treatments. Subterranean clover was the most widely sown species. The evaluation of enteric emissions was limited by the animals' low adherence to GreenFeed®, likely due to their "nervous temperament," but also due to the short experimental period and the very high ambient temperature. It was concluded that natural pasture contributed to the accumulation of soil fertility, while cultivated pastures, especially those rich in legumes, improved the nutritional quality of the forage. It is suggested that future studies use more docile animals and in greater numbers during a period of the year with milder temperatures.
This research aimed to evaluate biomass production, botanical composition and quality, as well as greenhouse gas (GHG) emissions in three types of pasture used by Mertolenga cattle. The study took place in 2024/25 in Portugal, at the INIAV Elvas, in three pastures of approximately 3 ha each, established in 2023/24: a sown pasture rich in grasses (GRA_75), a sown pasture rich in legumes (LEG_75), and a natural pasture (NAT) used as a reference. Soil samples were collected for analysis of organic matter and nutrient contents. Between February 20, 2025, and July 18, 2025, biomass production was monitored weekly with a Rising Plate Meter (RPM). On April 28, 2025, four 0.25 m2 samples were collected per treatment to evaluate botanical composition. Enteric GHG emissions were estimated with GreenFeed® equipment. The results showed that the soil under natural pasture had higher organic matter and micronutrient contents such as Fe, Mn, Cu, and Zn, while cultivated pasture had higher P and Mg contents. LEG _75 had higher CP values (9.2%), lower fiber content, and higher digestibility (50.9%). No significant differences were observed in botanical composition, which was dominated by grasses in all treatments. Subterranean clover was the most widely sown species. The evaluation of enteric emissions was limited by the animals' low adherence to GreenFeed®, likely due to their "nervous temperament," but also due to the short experimental period and the very high ambient temperature. It was concluded that natural pasture contributed to the accumulation of soil fertility, while cultivated pastures, especially those rich in legumes, improved the nutritional quality of the forage. It is suggested that future studies use more docile animals and in greater numbers during a period of the year with milder temperatures.
Description
Keywords
emissão de gases pastagens qualidade nutricional raça Mertolenga sustentabilidade ambiental. environmental sustainability gas emissions Mertolenga breed nutritional quality pastures.