Navegando por Autor "Fontes Neto, Daniel Torres"

Agora exibindo 1 - 1 de 1
  • Imagem de Miniatura
    Dissertação
    Acesso aberto (Open Access)
    Extrato de Ascophyllum nodosum (L.) Le Jolis sob diferentes doses na cultura da soja
    (Universidade Estadual do Norte do Paraná, 2017-08-22) Fontes Neto, Daniel Torres; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449; Bellettini, Silvestre; https://orcid.org/0000-0001-6769-544X; http://lattes.cnpq.br/0540747739983343; Saldanha, Lilian de Aguiar; http://lattes.cnpq.br/7215869321119292
    Bioactivators are complex substances that promote overall plant balance, favouring the expression of their genetic potential. They can also increase resistance to biotic and abiotic stresses, improve soil fertility, promote plant growth and enhance productivity. Anthropogenic activities within agrosystems influence soil quality; accordingly, the microbial community is highly sensitive to such changes, making it an excellent bioindicator of soil quality. Bioactive substances derived from the marine alga Ascophyllum nodosum have proven highly beneficial for crop yield and quality, as well as soil health. The aim of this study was to evaluate the effect of A. nodosum extract applied at different rates on the soybean crop. Field trials were conducted over the 2014/15 (Trial 1) and 2015/16 (Trial 2) growing seasons, with an additional greenhouse experiment carried out in 2016/17. Field trials were arranged in a randomised complete block design, comprising 4 treatments with 5 replicates (Trial 1) and 5 treatments with 4 replicates (Trial 2). In Trial 1, treatments comprised an untreated control (T1), and applications of A. nodosum 29% extract at 2.0 mL kg⁻¹ of seed, followed by topdressing sprayings with increasing rates of seaweed extract: 0.5 L ha⁻¹ (T2), 1.0 L ha⁻¹ (T3) and 2.0 L ha⁻¹ (T4). In Trial 2, treatments were: untreated control (T1); seed treatment at 2.0 mL kg⁻¹ plus topdressing spraying at 1.0 L ha⁻¹ of 29% extract (T2); seed treatment at 2.0 mL kg⁻¹ of 29% extract plus topdressing sprayings with increasing rates of 9% extract: 1.0 L ha⁻¹ (T3), 2.0 L ha⁻¹ (T4) and 3.0 L ha⁻¹ (T5). The third experiment was carried out under greenhouse conditions in a completely randomised design, comprising two treatments: untreated control (T1), and seed treatment at 2.0 mL kg⁻¹ of 29% extract plus topdressing spraying at 1.0 L ha⁻¹ of 9% extract (T2). Topdressing applications were performed at growth stages R1 and R5, with the total rate divided equally between the two sprayings. Evaluations included Total Organic Carbon (TOC), Microbial Biomass Carbon (MBC), Basal Soil Respiration (BSR), Metabolic Quotient (qCO₂) and Microbial Quotient (qMIC), alongside routine soil chemical analysis and crop agronomic assessments. Data were subjected to analysis of variance, with means compared by Tukey’s test (p < 0.05). In the 2014/15 trial, treatment T3 produced the most favourable results across all evaluated variables. In the 2015/16 trial, although differences were not statistically significant due to abiotic influences, T3 consistently showed a trend towards higher yield and improved microbial indicators. In the greenhouse trial, T2 significantly increased stem diameter and leaf area, demonstrating enhanced tolerance to water stress. Seed treatments combined with foliar applications of commercial Ascophyllum nodosum extracts (Acadian® and/or Toggle®) proved effective in soybean, increasing yield under varying moisture conditions without adversely affecting the soil microbial community.