Nitrogênio e potássio são os nutrientes mais extraídos e exportados pela cultura do rabanete, sendo imprescindíveis para a produtividade e qualidade das raízes produzidas. Desta forma, o presente estudo foi desenvolvido com o objetivo de avaliar alterações no crescimento de plantas e qualidade de raízes de rabanete em função de doses de potássio e fontes de nitrogênio. O experimento foi conduzido em delineamento inteiramente casualizado, com tratamentos arranjados em esquema fatorial 4 x 2, sendo quatro doses de potássio (K), 0, 70, 140 e 210 kg ha-1 de K2O e duas fontes de nitrogênio (N), sulfato de amônio e nitrato de cálcio, com quatro repetições. As plantas foram avaliadas quanto ao crescimento, rendimento, qualidade bioquímica das raízes e atividade da redutase do nitrato nas folhas. Os tratamentos não influenciaram as características de crescimento e rendimento: massa fresca de folhas, massa seca de folhas, área foliar total, comprimento e diâmetro de raiz. A adubação potássica aumentou o conteúdo de vitamina C nas raízes de rabanete e a atividade da redutase do nitrato nas folhas, principalmente quando a fonte de N utilizada foi o nitrato de cálcio. O maior valor de índice SPAD foi obtido na dose de 51 kg ha-1 de K2O. A utilização do sulfato de amônio propiciou maior teor de sólidos solúveis nas raízes.
The increasing water demand of crops in response to climate change; the prospect of expanded irrigated areas; the population growth; and competition with multiple uses of water affect the availability of water resources for agriculture. Thus, measures are required that involve the adoption of irrigation-management strategies able to increase water savings without compromising crop yield, especially in semi-arid conditions, where water resources are limited, and in large-scale commercial cultivation such as in 'Tommy Atkins' and 'Palmer' mango, the second most widely grown irrigated fruit crop. The objective of this study was to examine the influence of irrigation systems (drip and micro-sprinkler) and deficit-irrigation strategies on the yield and water use efficiency (WUE) of 'Tommy Atkins' and 'Palmer' mango trees. The study was developed through two experiments conducted in the Irrigated Perimeter of Ceraíma, located in municipality of Guanambi - BA, Brazil. Two trials were carried out in a completely randomized design. For the 'Tommy Atkins' cultivar, 12 strategies were tested, involving regulated deficit irrigation (RDI) by micro-sprinkler irrigation and partial rootzone drying (PRD) by drip, in three production cycles. For ‘Palmer’ mango, 10 irrigation strategies were evaluated under the same previously described conditions, in only one production cycle. The reduction in water application in RDI was 25 and 50% of the crop evapotranspiration (ETc); and, in PRD, 20, 40 and 60% ETc. ‘Tommy Atkins’ mango achieved higher yields under micro-sprinkler irrigation with full irrigation and in the strategies involving the application of 50 and 75% ETc in stages II and III. These two strategies also provided greater WUE, along with PRD40. Water use efficiency was lower in the third evaluation cycle when compared with the first. ‘Palmer’ mango showed higher yields and WUE under drip irrigation, with the best yields achieved with full irrigation and in the strategies of PRD100, 80%, 60% and RDI with 50% ETc in stage III. The best WUE was obtained in PRD with 60 and 40% ETc.
In October 2020, sooty moulds were found covering the leaves of neem trees (Azadirachta indica) in Vitória da Conquista, Bahia, Brazil. Sooty moulds usually grow on honeydew secreted by insects. However, in this observation, insects were not visible on the sooty mould‐infected plants. Rather, the sooty mould grew on the host secretions. Inoculation was performed to confirm the ability of the fungus to grow on host nectaries. Based on the morphological features and phylogenetic analysis, Capnodium alfenasii was identified as the sooty mould agent. To our knowledge, this is the first report on the occurrence of this fungus on neem plants.
RESUMO:Estudou-se o efeito de duas estratégias de irrigação na produção e eficiência de uso da água (EUA) da mangueira "Palmer", em dois experimentos: Irrigação com Déficit Controlado (RDI) sob microaspersão e Irrigação Lateralmente Alternada (PRD), sob gotejamento, em Guanambi-BA, com delineamento experimental em blocos casualizados com cinco tratamentos e quatro repetições. Na RDI: T1, irrigação plena, 100% ETc, nas três fases de desenvolvimento dos frutos: fase I, pegamento dos frutos; fase II, expansão dos frutos e fase III, maturação fisiológica; T2, 100% da ETc nas fases II e III e 50% da ETc na fase I; T3, 100% da ETc nas fases I e III e 50% da ETc na fase II; T4, 100% ETc nas fases I e II e 50% da ETc na fase III; T5, irrigação com 50% da ETc nas fases I, II e III; e na PRD nas três fases: T1, irrigação plena, 100% da ETc no sistema de gotejamento convencional; T2, 100% ETc; T3, 80% da ETc; T4, 60% da ETc e T5, 40% da ETc. A PRD com 40% da ETc reduz a produtividade da mangueira "Palmer" quando comparado à irrigação plena e PRD com 100% daETc. A RDI com 50% da ETc na fase III possibilita maior produtividade comparado à aplicação de 50% da ETc nas três fases. Não houve alteração na EUA entre os tratamentos. PALAVRAS-CHAVE: Mangiferaindica,manejo da irrigação, fruticultura PRODUCTION AND EFFICIENCY OF WATER USE IN 'PALMER' HOSE UNDER IRRIGATION STRATEGIES WITH WATER DEFICITABSTRACT: Aiming at evaluating the effect of two irrigation strategies on the production and water-use efficiency (WUE) of 'Palmer' mango trees, we developed two experiments: one of them used Regulated Deficit Irrigation (RDI), irrigated by micro sprinklers, and the other one 1 Acadêmico (a) de Agronomia, IF Baiano, Guanambi-Bahia.
SUMMARY:We aimed to understand two strategies of deficit irrigation and their effects on yield and water-use efficiency (WUE) in 'Tommy Atkins' mango trees, for three consecutive cycles. In the experiment with Regulated Deficit Irrigation (RDI), the treatments were: T1, full irrigation at every fruit development stage, 100% of ETc; T2, 100% of Etc at stages II and III Rootzone Drying (PRD) for the three crop stages: T1, 100% of ETc, conventional dripping irrigation; T2, 100%; T3, 80% of ETc; T4, 60% of ETc and T5, 40% of ETc. As for the treatments T2, T3, T4 and T5, the side to be irrigated was alternated every 15 days. At the end of 3 production cycles, we observed a reduction in productivity when RDI was applied at SI.The water-use efficiency was higher in the first cycle in relation to the third cycle under RDI.The PRD with 80% of ETc maintains the productivity and with 40% of ETc, increases WUE. KEYWORDS: evapotranspiration, fruit production, Mangifera indica IRRIGAÇÃO COM DÉFICIT EM CICLOS CONSECUTIVOS
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