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Impacte de diferentes culturas de cobertura nos nemátodes do solo num campo na Golegã
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A intensificação da produção agrícola associada ao uso de nematodicidas tem vindo a causar a degradação do solo, comprometendo as propriedades físico-químicas e o status biológico. Dada a urgência de encontrar alternativas sustentáveis, as culturas de cobertura emergem como solução promissora.
Este estudo avaliou o impacto das culturas de cobertura na nematofauna e na incidência de nemátodes fitoparasitas, em particular, os nemátodes de quisto do género Heterodera. O ensaio foi realizado na Golegã, onde foram testadas três culturas de cobertura: consociação de brássicas e gramíneas, consociação de brássicas, gramíneas e leguminosas, e consociação de gramíneas e leguminosas. As amostras de solo foram recolhidas antes da sementeira, dois meses depois e após a incorporação das culturas no solo.
Os resultados demonstraram que a consociação de brássicas e gramíneas foi a mais eficaz na redução da população de nemátodes fitoparasitas, promovendo simultaneamente o aumento das populações de nemátodes de vida livre, bacteriófagos e predadores, essenciais à boa saúde do solo. A mistura de gramíneas e leguminosas, pelo contrário, levou ao aumento da população das fitoparasitas. A consociação de brássicas, gramíneas e leguminosas desencadeou um efeito intermédio, reduzindo moderadamente as populações fitoparasitas e promovendo o crescimento das populações de bacteriófagos.
A identificação morfológica dos nemátodes Heterodera spp. revelou-se problemática e, por vezes, inconclusiva. Entre os quistos observados, 50% pertenciam à espécie Heterodera schachtii, 30% à espécie Heterodera zeae, enquanto que nos restantes 20% não foi possível identificar a espécie. A confirmação da identificação destas espécies foi efetuada através da observação das características morfológicas e da análise molecular, confirmando a importância de ambos os métodos para uma identificação precisa.
A presença destas duas espécies é justificada pelo histórico da parcela, com o cultivo de milho e de beterraba, observando-se a viabilidade dos quistos de H. schachtii (nemátode de quisto da beterraba-sacarina) após 16 anos sem a realização da cultura hospedeira.
Impact of different cover crop cultures on soil nematodes in a field in Golegã The intensification of agricultural production associated with the use of nematicides has been causing soil degradation, compromising its physico-chemical properties and biological status. Given the urgency of finding sustainable alternatives, cover crops emerge as a promising solution. This study evaluated the impact of cover crops on nematofauna and on the incidence of nematodes, in particular of cyst nematodes of Heterodera genus. The trial was conducted in the Golegã region, where three cover crop mixtures were tested: a mixture of brassicas and grasses, a mixture of brassicas, grasses, and legumes, and a mixture of grasses and legumes. Soil samples were collected before sowing, two months after sowing, and after the incorporation of the cover crops into the soil. The results showed that the mixture of brassicas and grasses was the most effective in reducing the population of plant-parasitic nematodes, while simultaneously promoting the increase of free-living nematodes, bacterivorous and predators. Conversely, the mixture of grasses and legumes led to an increase in the population of plant-parasitic nematodes. The mixture of brassicas, grasses, and legumes showed an intermediate effect, moderately reducing the populations of plant-parasitic nematodes and promoting the growth of bacteriophage populations. The morphological identification of Heterodera spp. nematodes proved problematic and, in some cases, inconclusive. Among the cysts observed, 50% belonged to the species Heterodera schachtii, 30% to the species Heterodera zeae, while in the remaining 20% it was not possible to identify the species. The confirmation of these species was carried out through the observation of morphological characteristics and molecular analysis, highlighting the importance of combining both methods for accurate identification. The presence of these two species is justified by the history of the plot, with maize and sugar beet cultivation, with the viability of H. schachtii cysts being observed after 16 years in the absence of the host crop.
Impact of different cover crop cultures on soil nematodes in a field in Golegã The intensification of agricultural production associated with the use of nematicides has been causing soil degradation, compromising its physico-chemical properties and biological status. Given the urgency of finding sustainable alternatives, cover crops emerge as a promising solution. This study evaluated the impact of cover crops on nematofauna and on the incidence of nematodes, in particular of cyst nematodes of Heterodera genus. The trial was conducted in the Golegã region, where three cover crop mixtures were tested: a mixture of brassicas and grasses, a mixture of brassicas, grasses, and legumes, and a mixture of grasses and legumes. Soil samples were collected before sowing, two months after sowing, and after the incorporation of the cover crops into the soil. The results showed that the mixture of brassicas and grasses was the most effective in reducing the population of plant-parasitic nematodes, while simultaneously promoting the increase of free-living nematodes, bacterivorous and predators. Conversely, the mixture of grasses and legumes led to an increase in the population of plant-parasitic nematodes. The mixture of brassicas, grasses, and legumes showed an intermediate effect, moderately reducing the populations of plant-parasitic nematodes and promoting the growth of bacteriophage populations. The morphological identification of Heterodera spp. nematodes proved problematic and, in some cases, inconclusive. Among the cysts observed, 50% belonged to the species Heterodera schachtii, 30% to the species Heterodera zeae, while in the remaining 20% it was not possible to identify the species. The confirmation of these species was carried out through the observation of morphological characteristics and molecular analysis, highlighting the importance of combining both methods for accurate identification. The presence of these two species is justified by the history of the plot, with maize and sugar beet cultivation, with the viability of H. schachtii cysts being observed after 16 years in the absence of the host crop.
Descrição
Mestrado em Engenharia Agronómica / Instituto Superior de Agronomia, Universidade de Lisboa
Palavras-chave
culturas agrícolas Heterodera identificação nemátodes de quisto nemátodes de vida livre agricultural crops cyst nematodes free-living nematodes identification
Contexto Educativo
Citação
Azevedo, D.S. Impacte de diferentes culturas de cobertura nos nemátodes do solo num campo na Golegã. Lisboa: ISA, 2024, 68 p. Dissertação de Mestrado
Editora
Instituto Superior de Agronomia, Universidade de Lisboa