Maturadores em cana-de-açúcar: qualidade da matéria-prima, poder calorífico da palha e residual na cultura
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Data
2017-02-20
Autores
Véliz, José Espinoza
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Universidade Estadual Paulista (Unesp)
Resumo
A cana-de-açúcar é uma cultura de grande importância econômica no Brasil, tanto pela produção de açúcar e etanol quanto pela produção de diversos subprodutos. Nas diferentes fases fenológicas da cultura, a fase de maturação é de alta importância em variedades de maturação precoce no início da safra, onde a cultura depende das condições climáticas, podendo, em condições desfavoráveis, proporcionar baixo teor de açúcar, acarretando em prejuízos quantitativos e qualitativos da matéria-prima. Deste modo, o uso de maturadores torna-se estratégia fundamental de manejo para atingir rendimentos satisfatórios. No presente estudo, objetivou-se avaliar a eficácia de maturadores na qualidade tecnológica, bioenergética, enzimática e fisiológica, além dos efeitos residuais na planta e soqueira. O estudo foi realizado com a variedade RB966928 (precoce), em cana-planta (2014/2015) e cana-soca (2015/2016), em Igaraçu do Tietê-SP. Os tratamentos foram os seguintes: glifosato, nas doses de 0,35; 0,45; 0,50 e 1,00 L ha-1 de produto comercial (PC) (0,126; 0,162; 0,240 e 0,480 kg de equivalente ácido (ea), respectivamente); trinexapaque-etílico, nas doses de 0,60; 0,80; 1,00 e 1,20 L ha-1 de PC, equivalente a 0,150; 0,200; 0,250 e 0,300 L i.a., respectivamente; sulfometurom-metílico, na dose de 0,02 kg ha-1 de PC ou 0,015 kg de i.a.; e testemunha sem aplicação de maturadores. Os tratamentos foram aplicados 60, 45, 30 e 15 dias antes da colheita (DAC), no período de março a maio (safra 2014/2015). Os resultados em pré-colheita permitiram concluir que, independente do maturador e da dose, todos alteraram a qualidade da matéria-prima, em que quanto maior DAC maior o acúmulo de sacarose. O glifosato elevou o teor de sacarose à medida que aumentou a dose e DAC, prejudicando a produtividade de colmos (TCH), de pol (TPH) e de açúcar (TAH) em cana-planta. O glifosato a 0,35 L ha-1 não prejudicou a TCH em função de DAC, e aumentou TPH e TAH, aos 45 DAC. No entanto, houve efeito residual do maturador aplicado em cana-planta para doses acima de 0,50 L ha-1 para cana-soca, prejudicando clorofila, crescimento da planta, porém aumentando o poder calorífico do palhiço. Trinexapaque-etílico melhorou a qualidade da matéria-prima à medida que se aumentou a dose e DAC, o que reduziu a altura das plantas, mas sem reduzir TCH em cana-planta. No entanto, o incremento da sacarose foi comprometido pela redução de TCH acima de 45 DAC. Em cana-planta, com trinexapaque-etílico em doses abaixo de 1,0 L ha-1 aos 60 DAC, houve um aumento de TPH e TAH, conteúdo de clorofila, número e altura de perfilhos. Os resíduos de trinexapaque-etílico em doses acima de 1,00 L ha-1, aplicadas em cana-planta aos 15 DAC, reduziram a TCH em cana-soca. Os maturadores, em doses recomendadas, aumentaram o teor de sacarose à medida que incrementaram os DAC, com maior magnitude para glifosato a 0,45 L, seguido de sulfometurom-metílico a 0,02 kg e trinexapaque-etílico a 0,80 L ha-1. O glifosato prejudicou a produtividade de cana e açúcar, tanto em cana-planta quanto em cana-soca. O sulfometurom-metílico a 0,02 kg e trinexapaque-etílico a 0,80 L ha-1 aumentaram a TPH e TAH até aos 60 DAC. O sulfometurom-metílico a 0,02 kg ha-1 manteve os níveis de clorofila, aumentou o poder calorífico do palhiço e não prejudicou a altura e número de perfilhos. Em geral, no ponteiro da planta, houve maior concentração de resíduos dos maturadores entre 15 a 45 DAA, assim como na rebrota. Na rebrota, o trinexapaque-etílico a 0,80 L ha-1 e sulfometurom-metílico a 0,02 kg ha-1 alteraram os componentes lignocelulósicos, assim como a atividade da enzima invertase ácida (SAI), invertase neutra (NI), sacarose fosfato sintase (SPS) e sacarose sintase (SuSy) a os 15 e 60 DAA. Todos os tratamentos incrementaram o conteúdo de sacarose quando aplicados com mais DAC. No entanto, o glifosato provocou dano em cana-planta e cana-soca pelo efeito residual. A dose de glifosato a 0,35 L ha-1 apresentou maior rendimento de açúcar (TAH) aos 45 DAC, trinexapaque-etílico e sulfometurom-metílico nas doses de 0,60 a 1,00 L ha-1 e 0,02 kg ha-1, respectivamente, apresentaram os melhores rendimentos de açúcar sem provocar redução do peso dos colmos.
Sugarcane is a crop of great economic importance in Brazil, both for the production of sugar and ethanol and for the production of various by-products. In the different phenological stages of the crop, the maturation stage is of high importance in early maturing varieties at the beginning of the harvest, where the crop depends on the climatic conditions, and can under favorable conditions, provide low sugar content, leading to quantitative losses and quality of the raw material. In this way, the use of ripeners becomes a fundamental management strategy to achieve satisfactory yields. In the present study, the objective of this study was to evaluate the efficacy of ripeners in the technological, bioenergetic, enzymatic and physiological quality, as well as the residual effects on plant and ratoon. The study was carried out with the variety RB966928 (early), in sugarcane cane-plant (2014/2015) and sugarcane ratoon-cane (2015/2016), in Igaraçu do Tietê-SP. Treatments were as follows: glyphosate at the doses of 0.35; 0.45; 0.50 and 1.00 L ha-1 of commercial product (PC) (0.126, 0.162, 0.240 and 0.480 kg of acid equivalent (ea), respectively); trinexapac-ethyl, at doses of 0.60; 0.80; 1.00 and 1.20 L ha-1 of PC, equivalent to 0.150; 0.200; 0.250 and 0.300 L i.a., respectively; sulfometurom-methyl, at a dose of 0.02 kg ha-1 PC or 0.015 kg a.i. and control without application of maturators. The treatments were applied at 60, 45, 30 and 15 days before harvest (DBH), from March to May (harvest 2014/2015). The pre-harvest results allowed us to conclude that, regardless of the ripener and the dose, all of them altered the quality of the raw material, where the higher DBH provided greater accumulation of sucrose. Glyphosate increased the sucrose content as the dose increased, impairing stem yield (TCH), pol (TPH) and sugar per ha (TAH) in sugarcane. Glyphosate at 0.35 L ha-1 did not impair TCH by DBH, and increased TPH and TAH at 45 DBH. However, there was a residual effect of the ripener applied on cane plant at doses above 0.50 L ha-1 for ratoon cane, damaging chlorophyll, plant growth, but increasing the calorific value of the straw. Trinexapac-ethyl improved the quality of the raw material as the dose and DBH increased, which reduced plant height, but without reducing TCH in cane plant. However, the increment of sucrose was compromised by the reduction of TCH above 45 DAC. In plant cane, with trinexapac-ethyl in low doses at 1.0 L ha-1 at 60 DBH, there was an increase of TPH and TAH, chlorophyll content, number and height of tillers. The trinexapac-ethyl residues above 1.00 L ha-1, applied in cane plant at 15 DBH, reduced TCH in ratoon cane. The ripeners, at recommended doses, increased the sucrose content as they increased DBH, with a higher magnitude for glyphosate at 0.45 L, followed by sulfometurom-methyl at 0.02 kg and trinexapac-ethyl at 0.80 L ha -1. Glyphosate impaired sugarcane and sugar yields, both in sugarcane and in sugar. Sulfometurom-methyl at 0.02 kg and trinexapaque-ethyl at 0.80 L ha-1 increased TPH and TAH up to 60 DBH. The sulfometurom-methyl at 0.02 kg ha-1, maintained chlorophyll levels, increased the calorific value of the straw and did not affect the height and number of tillers. In general, in the pointer of the plant, there was a greater concentration of residues of the ripeners between 15 and 45 DAA, as well as in regrowth. At regrowth, trinexapac-ethyl at 0.80 L ha-1 and sulfometurom-methyl at 0.02 kg ha-1 altered the lignocellulosic components, as well as the activity of the acid invertase enzyme (SAI), neutral invertase (NI), sucrose-phosphate synthase (SPS) and sucrose synthase (SuSy) at 15 and 60 DAA. All treatments increased the sucrose content when applied with more DBH. However, glyphosate caused damage in cane plant and ratoon cane by residual effect. The dose of glyphosate at 0.35 L ha-1 presented higher sugar yield (TAH) at 45 DBH, trinexapac-ethyl and sulfometurom-methyl at doses of 0.60 to 1.00 L ha-1 and 0.02 kg ha-1, respectively, presented the best yields of sugar without reducing the weight of the stalks.
Sugarcane is a crop of great economic importance in Brazil, both for the production of sugar and ethanol and for the production of various by-products. In the different phenological stages of the crop, the maturation stage is of high importance in early maturing varieties at the beginning of the harvest, where the crop depends on the climatic conditions, and can under favorable conditions, provide low sugar content, leading to quantitative losses and quality of the raw material. In this way, the use of ripeners becomes a fundamental management strategy to achieve satisfactory yields. In the present study, the objective of this study was to evaluate the efficacy of ripeners in the technological, bioenergetic, enzymatic and physiological quality, as well as the residual effects on plant and ratoon. The study was carried out with the variety RB966928 (early), in sugarcane cane-plant (2014/2015) and sugarcane ratoon-cane (2015/2016), in Igaraçu do Tietê-SP. Treatments were as follows: glyphosate at the doses of 0.35; 0.45; 0.50 and 1.00 L ha-1 of commercial product (PC) (0.126, 0.162, 0.240 and 0.480 kg of acid equivalent (ea), respectively); trinexapac-ethyl, at doses of 0.60; 0.80; 1.00 and 1.20 L ha-1 of PC, equivalent to 0.150; 0.200; 0.250 and 0.300 L i.a., respectively; sulfometurom-methyl, at a dose of 0.02 kg ha-1 PC or 0.015 kg a.i. and control without application of maturators. The treatments were applied at 60, 45, 30 and 15 days before harvest (DBH), from March to May (harvest 2014/2015). The pre-harvest results allowed us to conclude that, regardless of the ripener and the dose, all of them altered the quality of the raw material, where the higher DBH provided greater accumulation of sucrose. Glyphosate increased the sucrose content as the dose increased, impairing stem yield (TCH), pol (TPH) and sugar per ha (TAH) in sugarcane. Glyphosate at 0.35 L ha-1 did not impair TCH by DBH, and increased TPH and TAH at 45 DBH. However, there was a residual effect of the ripener applied on cane plant at doses above 0.50 L ha-1 for ratoon cane, damaging chlorophyll, plant growth, but increasing the calorific value of the straw. Trinexapac-ethyl improved the quality of the raw material as the dose and DBH increased, which reduced plant height, but without reducing TCH in cane plant. However, the increment of sucrose was compromised by the reduction of TCH above 45 DAC. In plant cane, with trinexapac-ethyl in low doses at 1.0 L ha-1 at 60 DBH, there was an increase of TPH and TAH, chlorophyll content, number and height of tillers. The trinexapac-ethyl residues above 1.00 L ha-1, applied in cane plant at 15 DBH, reduced TCH in ratoon cane. The ripeners, at recommended doses, increased the sucrose content as they increased DBH, with a higher magnitude for glyphosate at 0.45 L, followed by sulfometurom-methyl at 0.02 kg and trinexapac-ethyl at 0.80 L ha -1. Glyphosate impaired sugarcane and sugar yields, both in sugarcane and in sugar. Sulfometurom-methyl at 0.02 kg and trinexapaque-ethyl at 0.80 L ha-1 increased TPH and TAH up to 60 DBH. The sulfometurom-methyl at 0.02 kg ha-1, maintained chlorophyll levels, increased the calorific value of the straw and did not affect the height and number of tillers. In general, in the pointer of the plant, there was a greater concentration of residues of the ripeners between 15 and 45 DAA, as well as in regrowth. At regrowth, trinexapac-ethyl at 0.80 L ha-1 and sulfometurom-methyl at 0.02 kg ha-1 altered the lignocellulosic components, as well as the activity of the acid invertase enzyme (SAI), neutral invertase (NI), sucrose-phosphate synthase (SPS) and sucrose synthase (SuSy) at 15 and 60 DAA. All treatments increased the sucrose content when applied with more DBH. However, glyphosate caused damage in cane plant and ratoon cane by residual effect. The dose of glyphosate at 0.35 L ha-1 presented higher sugar yield (TAH) at 45 DBH, trinexapac-ethyl and sulfometurom-methyl at doses of 0.60 to 1.00 L ha-1 and 0.02 kg ha-1, respectively, presented the best yields of sugar without reducing the weight of the stalks.
Descrição
Palavras-chave
glifosato, maturação, Saccharum spp., sacarose, sulfometurom-metílico, trinexapaque-etílico., glyphosate, maturation, Saccharum spp., sucrose, sulfometurom-methyl, trinexapac-ethyl.