Uso de enxofre na cultura da cebola em sistemas orgânico e convencional para o manejo de tripes e míldio e análise de rendimento

Abstract

RESUMOO objetivo deste estudo foi avaliar o efeito de doses de enxofre aplicado em cobertura no solo no manejo de tripes, Thrips tabaci (Thysanopetra: Thripidae), e de míldio, Peronospora destructor, produtividade e rendimento pós-colheita de cebola, em sistemas orgânico e convencional. Palavras-chave: Allium cepa, Thrips tabaci, Peronospora destructor, agroecologia, produtividade. ABSTRACTThe objective of this study was to evaluate the effect of sulphur doses applied in soil cover on the management of thrips, Thrips tabaci (Thysanopetra: Thripidae), downy mildew (Peronospora destructor), yield and postharvest of onion under organic and conventional system. In separate experiments for both systems were applied the following treatments: sulphur doses of 25 kg ha-1, 50 kg ha-1, and 75 kg ha-1 and control without application. Sulphur doses were applied associated with cover fertilization at 33 and 36 days after transplanting for organic and conventional systems, respectively. The sulphur source was the Sulfacal® fertilizer (Ca = 16%, S = 13%). Phytosanitary management, yield and post-harvest were not influenced by the treatments. The addition of sulphur did not alter the other physical-chemical attributes of the soil. Leaf sulphur level was increased according to a positive linear relationship in organic system y = 4.2 + 0.02x (R2 = 0.41%, p = 0.0023) and was incremented by the dose of 75 kg ha-1 in the conventional system.

Acúmulo de macronutrientes em bulbos de cebola em função de épocas de aplicação de enxofre em condição tropical de baixa altitude

“…The maximum accumulation of sulfur by the plant occurs during the period of full development, during bulbing (Pôrto et al, 2007;Souza et al, 2017). In this phase, there is a greater translocation of photoassimilates for the formation of the bulb and, consequently, a greater demand for nutrients, probably due to the increase in metabolic activity associated with hormonal activity and cell division and growth for the formation of new tissues (Noda, 2018).…”

Qualidade de sementes de soja provenientes de plantas tratadas com produtos alternativos isolados e associados a fungicida

“…Em função disso, medidas alternativas de controle têm sido buscadas como a utilização de quitosana (Katiyar et al, 2015), Bacillus subtilis (Lanna Filho et al, 2010), enxofre (De Souza et al, 2017) e hipoclorito de sódio (Walter et al, 2009). No entanto, existem poucas informações sobre a interferência na qualidade fisiológica e sanitária de sementes de soja, cujas plantas foram submetidas a tratamentos alternativos para o controle de doenças foliares.…”