REDUÇÃO DA ADUBAÇÃO E MELHORIA DAS CARACTERÍSTICAS DO SUBSTRATO COM O USO DO HIDROGEL NA PRODUÇÃO DE MUDAS DE <i>Eucalyptus dunnii</i> Maiden

Abstract

RESUMOO objetivo do estudo foi avaliar se a presença do hidrogel afeta as propriedades físicas e químicas do substrato e a relação do hidrogel com doses de adubação no desenvolvimento de mudas. No substrato com presença e ausência do hidrogel foi realizada análise de características químicas e físicas. A produção de mudas foi conduzida em casa de vegetação sob irrigação reduzida, utilizando delineamento inteiramente casualizado em arranjo bifatorial 2 x 6, em que os níveis do fator "A" referiram-se a presença (6 g L -1 ) ou ausência do hidrogel e os níveis do fator "B", às doses do fertilizante de liberação controlada -FLC (0; 25; 50; 75; 100 e 125% da dose usual). Após 90 dias de semeadura foi realizada a avaliação de parâmetros morfológicos das mudas. O uso do hidrogel apresentou melhoria das características físicas e químicas do substrato, principalmente aos atributos que envolvem retenção e disponibilização de água às plantas. Com a adição do hidrogel e aproximadamente 50-75% da adubação convencional, houve aumento da altura, diâmetro de coleto, massa seca radicular e total, além do índice de qualidade de Dickson. Com o uso do hidrogel e adubação superior a 100% há redução do crescimento das mudas. Já, sem a adição do polímero, o melhor desempenho das mudas é obtido com doses superiores a 100% da adubação convencional. Em geral, o uso do polímero permite a redução em, pelo menos, 25% da adubação convencional (6 g L -1 ), podendo ser reduzida em até 50%. Palavras-chave: produção de mudas; fertilizantes de liberação controlada; polímero hidrorretentor; economia de fertilizantes. ABSTRACTThe aim of the study was to evaluate if the presence of hydrogel affects the physical and chemical properties of the substrate and the ratio of hydrogel in the fertilization rates of developing seedlings. In the substrate with and without hydrogel, it was carried out an analysis for the chemical and physical characteristics. The production of seedlings was conducted in a greenhouse under reduced irrigation using a randomized design factorial arrangement 2 X 6 in which the levels of factor 'A' referred to the presence (6 g L -1 ) or absence of hydrogel and the levels of factor 'B' to the doses of controlled-release fertilizer -FLC

Precision tools for irrigation management of tomato seedlings

“…This result indicate that the irrigation depth applied to the substrate with hydrogel was readily available to the seedlings. Navroski et al (2016) found larger SBD when using gel on the substrate or soil, and explained this result by the improved water retention and use by plants.…”

“…Similar result was found during the vegetative development of sweet pepper plants with the use of hydrogel (TITTONELL; GRAZIA; CHIESA, 2002). Navroski et al (2016), and Bernardi et al (2012) evaluated the use of hydrogel (6 g L -1 ) for the production of eucalyptus seedlings and found that the use of hydrogel favored the development of the seedlings, reducing the requirement of nutritional supplementation in about 20%.…”

“…This result indicates more root development in the substrate with hydrogelnot associated to their growth in depth, which was limited due to the tray cell area, but to the development of secondary roots. Navroski et al (2016) associated the development of these roots with the effect of the use of hydrogel. Secondary roots are associated with water absorption, thus, seedlings with high numbers of these roots tend to have better resistance to water deficit.…”

Irrigation Regimes on Growth and Metabolic Processes of Enterolobium contortisiliquum Seedlings

“…These results corroborate those obtained by Navroski et al (2015) and Felippe et al (2016) on the production of the genus Eucalyptus seedlings. The increase in biomass with the addition of water-retaining polymer occurs due to the reduction of percolation of irrigation water and improvement in the aeration and drainage in soil (Bernardi et al, 2012) as well as the reduction in nutrient leaching (Navroski et al, 2015), which contributes directly to the improvement of the nutritional status of the plant, reducing the consumption of fertilizers from 25% to 50% (Navroski et al, 2016).…”

“…In addition, the use of synthetic conditioners is reported to contribute toward an increase in the water retention capacity of the substrate, which reduces the frequency of irrigation, and thus, allows more effective use of resources from the culture medium and water, which ultimately optimizes crop yield (Navroski et al, 2015). Moreover, the use of water-retaining polymers improves the chemical and physical characteristics of the substrate, allowing better utilization of the nutrients incorporated into the culture medium (Felippe et al, 2016;Navroski et al, 2016) This investigation sought to identify the influence of different watering regimes and the addition of water-retaining polymer to the substrate on the initial growth and metabolic processes of E. contortisiliquum seedlings. The main questions that we aimed to answer are: a) Is the growth of E. contortisiliquum seedlings dependent on the watering regime adopted?…”