A meta-analysis of biochar application to manage plant diseases caused by bacterial pathogens

The current agricultural scenario faces diverse challenges, among which phytosanitary issues are crucial. Plant diseases are mostly treated with chemicals, which cause environmental pollution and pathogen resistance. In light of the UN Sustainable Development Goals (SDGs), the biochar alternative use to chemical inputs fits into at least six of the proposed goals (2, 3, 7, 13, 15, and 17), highlighting the 12th, which explains responsible consumption and production. Biochar is valuable for inducing systemic resistance in plants because it is a practical and frequently used resource for improving physical, chemical, and biological soil attributes. This review assessed the beneficial and potential effects of applying biochar to agricultural soils on bacterial pathogen management. Such application is a recent strategy; therefore, this research evaluated 20 studies that used biochar to manage plant diseases caused by pathogens inhabiting the soil in different systems. The effectiveness of biochar application in controlling plant diseases has been attributed to its alkaline pH, which contributes to the growth of beneficial microorganisms and increases nutrient availability, and its porous structure, which provides habitat and protection for soil microbiome development. Therefore, the combined effect of improvements on soil attributes through biochar application aids pathogen control. Biochar application helps manage plant diseases through different mechanisms, inducing plant resistance, increasing activities and abundance of beneficial microorganisms, and changing soil quality for nutrient availability and abiotic conditions.

Varabilidade temporal da precipitaçäo pluvial: nível de nitrogênio no solo e produtividade de cultivares de girassol / Temporal variability of the pluvial precipitation: nitrogen amount in the soil over sunflower income

Objetivando avaliar os efeitos provocados pela variabilidade temporal da precipitaçäo pluvial sobre o desenvolvimento e produtividade da cultura do girassol (Helianthus annuus L.) em funçäo da adubaçäo nitrogenada e cultivares, realizaram-se experimentos nos anos de 1995, 1996, 1998, em Alagoinha-PB, e, no ano de 1998, em Esperança-PB, com a cultura do girassol, analisando-se quatro níveis de nitrogênio (0, 30, 60 e 90kg.ha-1), dois cultivares (uma precoce e uma tardia), em blocos casualizados, com 4 repetiçöes. Durante a conduçäo dos experimentos, foram analisados os estádios fenológicos, fitomassa, rendimento e precipitaçäo pluvial durante o ciclo da cultura. Com relaçäo aos resultados, verificou-se para o município de Alagoinha-PB uma precipitaçäo pluvial média anual do período de 1.018,6mm. As respostas dos tratamentos adotados para a cultura sobre as variáveis analisadas estiveram na dependência da distribuiçäo da precipitaçäo pluvial durante as fases de desenvolvimento dos cultivares. Foi observada também uma grande variaçäo na resposta do girassol em relaçäo aos níveis de nitrogênio e às cultivares em funçäo do tempo