Aclimatização de mudas de cana-de-açúcar em ambiente protegido sob dois tipos de malhas de sombreamento

Abstract

RESUMOObjetivou-se, com este trabalho, analisar a radiação solar global, a temperatura do ar e seus efeitos no crescimento e desenvolvimento de mudas de cana-de-açúcar em aclimatização sob dois tipos de cobertura em ambiente protegido. A pesquisa foi conduzida na área experimental do Centro de Tecnologias Estratégicas do Nordeste, Igarassu, PE. O ambiente protegido foi coberto com plástico leitoso associado a dois tipos de malhas de sombreamento: malha termorrefletora e malha preta; as variáveis estudadas foram: meteorológicas (radiação solar, temperatura do ar) e biométricas (comprimento do colmo, diâmetro do colmo, comprimento da folha, número de folhas, altura da planta e área foliar). Utilizaram-se 12 bandejas sendo escolhidos, aleatoriamente, quatro tubetes por bandeja por tratamento para o acompanhamento biométrico. O delineamento experimental foi inteiramente casualizado utilizando-se o teste de Tukey (p < 0,05) para comparação entre as médias das variáveis biométricas. O ambiente com malha termorrefletora proporcionou os melhores resultados de desenvolvimento das mudas em decorrência da maior disponibilidade de radiação solar global nesse ambiente de produção. Palavras-chave: cultivo protegido, elementos meteorológicos, microclimaAcclimatization of sugarcane seedlings in a greenhouse under two types of shading screens ABSTRACT This study aimed to analyse the global solar radiation, temperature and their effects on the growth and development of seedlings of sugarcane under acclimatization in two types of coverages in a protected environment. The study was conducted in the experimental area at the Center for Strategic Technologies in the Northeast -Igarassu, PE. The greenhouse was covered with white polyethylene and divided into two: one associated with the thermal reflector mesh and another associated with black mesh. The studied variables were: weather (solar radiation, air temperature) and biometric (stem length, stem diameter, leaf length, leaf number, plant height and leaf area). For biometric monitoring, 12 randomly selected trays with four tubes per tray per treatment were used. The experimental design was completely randomized, using the Tukey test (p < 0.05) for comparison between means. The environment under thermal reflector mesh provided the best results for seedling development because of greater availability of solar radiation in the production environment.

Biophotonics: Acclimation of Pre-Sprouted Sugarcane Seedlings in Protected Environment

“…found a 2.3 ºC increase in the average air temperature inside the protected environment in October. Guiselini et al (2013) observed, in the municipality of Igarassu, PE, an average air temperature inside the protected environment of 0.44 ºC, above the one recorded in the external environment.…”

Effects of Photoselective Shade Nets on Early Growth of Sugarcane Seedlings

“…Moreover, it can be confirmed due to negative correlation of GSR, PAR, and Tair with plant height (r = -0.68, -0.73, and -0.41, respectively) and stem length (r = -0.89, -0.92, and -0.66, respectively). Photoselective shade nets helped attenuate micrometeorological hazards and reduce extreme changes in the protected environments, which are unfavorable to seedling growth, thus allowing maintenance of growth factors within suitable ranges during early seedling development (Guiselini et al, 2013;Ferrari & Leal, 2015).…”

“…Between 13 and 19 DAP (Growth), seedlings were sensitive to micrometeorological elements such as Tair, GSR, and RH ( Figure 1B). Thus, during early growth, shading is crucial in protected environments for sugarcane seedling production against high temperature and solar radiation intensity (Almeida Neto, 2019;Guiselini et al, 2013;Silva et al, 2019). Air relative humidity (RH) was positively correlated with biometric parameters, including plant height (PH) (r = 0.77) and stem length (SL) (r = 0.82).…”

“…This confirms the behavior started at 27 DAP, since which seedlings required more GSR, PAR, and Tair to increase LAI (r = 0.68, 0.63, and 0.56, respectively) and AGRsd (r = 0.29, 0.33, and 0.42, respectively). Guiselini et al (2013) reported that sugarcane seedlings had an increased LAI under greater availability of GSR (37.66 MJ m -² week -1 ) in the growing environment. Physiological changes have also been observed when GSR and PAR rates were reduced in sugarcane plants (Elli et al, 2016).…”

Productive, morphological and qualitative characteristics of sugarcane in the understory tree species in agroforestry systems

“…The angico understory showed higher SL values in the first year, Similarly, one can observe a reduction in SD from 2010 for the understory of Eucalypt and guapuruvu, and similar medians for angico and canafístula, respectively between the years (Table 2). In this context, Guiselini et al (2013) analyzed the acclimation of sugarcane seedlings in greenhouse under two types of shading screens, found a limitation of SL and SD of the sugarcane when grown in an environment with less availability of solar radiation. This feature was not observed in bracatinga understory, where levels were higher in the last two years.…”