Resposta de cultivares de cana-de-açúcar a lâminas de irrigação via gotejamento subsuperficial
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Data
2018-10-30
Autores
Fischer Filho, João Alberto
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Universidade Estadual Paulista (Unesp)
Resumo
A cana-de-açúcar é cultivada em muitos países e em diversos ambientes de produção, sendo a água um fator limitante para que a cultura tenha elevadas produtividades. O objetivo deste trabalho foi avaliar o efeito de lâminas de irrigação, via gotejamento subsuperficial, nas características biométricas, na qualidade tecnológica, produtividade e eficiência do uso da água (EUA) de cinco cultivares, em segunda soca. O delineamento experimental foi o de blocos balanceados, com 12 blocos e dois fatores: cultivares (CTC 4, IACSP93-3046, RB86-7515, IACSP95-5000 e IAC91-1099) e lâminas de irrigação (sequeiro, deficitária e suplementar). A necessidade de água foi estimada por meio das variáveis climáticas. A partir da evapotranspiração da cultura (ETc) estimada foram definidas lâminas de irrigação equivalentes a 100% da ETc para o tratamento suplementar e 50% para o deficitário, e a irrigação foi realizada sempre que ocorreu déficit de 20 mm . O uso da irrigação proporcionou condições para as plantas se estabelecerem e expressarem melhor suas características biométricas, principalmente no início do desenvolvimento vegetativo; com destaque as cultivares RB86-7515 (com maiores alturas, diâmetros de colmos e área foliar), a CTC 4 com maior perfilhamento e a IAC91-1099 (maiores números de folhas e índice de área foliar). Não foram encontradas diferenças estatísticas significativas para sólidos solúveis totais e teor de fibra. As quantidades de sacarose no caldo (POL) e na cana (PC) não diferiram entre as cultivares, porém, a irrigação suplementar proporcionou maiores valores dos parâmetros avaliados. Os teores de pureza de todos tratamentos foram superiores ao recomendado (85%) e diferiram entre as cultivares. No regime de irrigação suplementar a cultivar IAC91-1099 apresentou maior valor de açúcares totais recuperáveis (ATR), igual a 165,62 kg t -1 e as maiores produtividades de colmos e de açúcares, 157,02 e 26,01 t ha -1 , respectivamente, podendo ser recomendada para plantio em áreas de sequeiro e irrigadas por gotejamento subsuperficial. A irrigação deficitária proporcionou ganhos médios nas produtividades de colmo e de açúcar semelhantes às da irrigação suplementar, com economia de água e energia.
Sugar cane is grown in many countries and diverse production environments, with water being a limiting factor for high crop yields. This study aimed to evaluate the effect of irrigation depths , under subsurface drip, on the biometric characteristics, technological quality, productivity and water use efficiency (WUE) of five cultivars in the third crop cycle . The experimental design was of balanced blocks, with 12 blocks and 2 factors: cultivars (CTC 4 , IAC SP 93 - 3046, RB86 - 7515, IAC SP 95 - 5000 and IAC91 - 1099) and irrigation depths (dry, deficit and supplementary) . The need for water was estimated by means of climatic variables. From the evapotranspiration of the crop estimated ( ETc ) irrigation depths equivalent to 100% of the ETc were defined for the supplementary treatment and 50% for the deficit, and irrigation was performed whenever there was a deficit of 20 mm . The use of irrigation provided conditions for plants to establish and better express th eir biometric characteristics, especially at the beginning of vegetative development ; highlighting the cultivars RB86 - 7515 (with higher heights, plant diameters and leaf area), CTC 4 with higher tillering and IAC91 - 1099 (higher leaf numbers and leaf area i ndex). No significant statistical differences were found for total soluble solids and fiber content . The amounts of sucrose in the juice (POL) and the cane (PC) did not differ among the cultivars, however, additional irrigation provided higher values of th e evaluated parameters . The purity levels of all treatments were higher than the recommended (85%) and differed between the cultivars . In the supplementary irrigation, the cultivar IAC91 - 1099 showed the highest total sugar value (ATR), equal to 165.62 kg t - 1 and the highest yields of stalks and sugars, 157.02 and 26.01 t ha - 1 , respectively, and can be recommended for planting in rainfed areas and irrigated by subsurface drip irrigation . The deficit irrigation provides average gains in sugar and sugar yields similar to those of supplementary irrigation, in addition to saving water and energy.
Sugar cane is grown in many countries and diverse production environments, with water being a limiting factor for high crop yields. This study aimed to evaluate the effect of irrigation depths , under subsurface drip, on the biometric characteristics, technological quality, productivity and water use efficiency (WUE) of five cultivars in the third crop cycle . The experimental design was of balanced blocks, with 12 blocks and 2 factors: cultivars (CTC 4 , IAC SP 93 - 3046, RB86 - 7515, IAC SP 95 - 5000 and IAC91 - 1099) and irrigation depths (dry, deficit and supplementary) . The need for water was estimated by means of climatic variables. From the evapotranspiration of the crop estimated ( ETc ) irrigation depths equivalent to 100% of the ETc were defined for the supplementary treatment and 50% for the deficit, and irrigation was performed whenever there was a deficit of 20 mm . The use of irrigation provided conditions for plants to establish and better express th eir biometric characteristics, especially at the beginning of vegetative development ; highlighting the cultivars RB86 - 7515 (with higher heights, plant diameters and leaf area), CTC 4 with higher tillering and IAC91 - 1099 (higher leaf numbers and leaf area i ndex). No significant statistical differences were found for total soluble solids and fiber content . The amounts of sucrose in the juice (POL) and the cane (PC) did not differ among the cultivars, however, additional irrigation provided higher values of th e evaluated parameters . The purity levels of all treatments were higher than the recommended (85%) and differed between the cultivars . In the supplementary irrigation, the cultivar IAC91 - 1099 showed the highest total sugar value (ATR), equal to 165.62 kg t - 1 and the highest yields of stalks and sugars, 157.02 and 26.01 t ha - 1 , respectively, and can be recommended for planting in rainfed areas and irrigated by subsurface drip irrigation . The deficit irrigation provides average gains in sugar and sugar yields similar to those of supplementary irrigation, in addition to saving water and energy.
Descrição
Palavras-chave
Saccharum spp., Eficiência do uso da água, Déficit hídrico, Irrigação localizada, Water use efficiency, Water deficit, Drip irrigation