Fertirrigação e pulverização foliar com silício em cana-de-açúcar e em cana-energia cultivada sob déficit hídrico
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Data
2021-08-31
Autores
Teixeira, Gelza Carliane Marques [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O cultivo irrigado de cana-de-açúcar e de cana-energia tem expandido nos últimos anos. Contudo, ao mesmo tempo tem ocorrido intensificação da restrição hídrica causada pelas mudanças climáticas. Por isso, é primordial pesquisas focadas em aumentar a tolerância dessas espécies de grande interesse agrícola, permitindo o uso da água com sustentabilidade. O fornecimento de silício (Si) pode contribuir para aumentar a eficiência no uso da água atenuando os danos causados pelo déficit hídrico. Mas não se conhece os efeitos do Si no cultivo de plantas de cana-de-açúcar e de cana-energia sob déficit hídrico com duração de 7 até 60 ou 160 dias após o transplantio. Além disso, exige-se um aprimoramento da técnica de aplicação. Essa pesquisa foi realizada objetivando avaliar os efeitos da aplicação de Si via fertirrigação associada com a pulverização foliar em parâmetros fisiológicos, bioquímicos e nutricionais em plantas de cana-de-açúcar e de cana-energia cultivadas sob déficit hídrico severo de dois períodos de duração. Foram realizados quatro experimentos em condição controlada. Inicialmente, foi avaliado o efeito da fertirrigação associada com pulverização foliar de Si aplicada somente na fase de formação de mudas em plantas de cana-de-açúcar (experimento I) e de cana-energia (experimento II) cultivadas sob déficit hídrico severo por período de 7 a 60 dias após o transplantio. Posteriormente, avaliou-se o efeito do Si nos mesmos modos de aplicação na fase de mudas e com complemento após o transplantio em plantas de cana-de-açúcar (experimento III) e de cana-energia (experimento IV) cultivadas sob déficit hídrico severo por período de 7 a 160 dias após o transplantio. O déficit hídrico severo diminuiu o conteúdo de água e o potencial hídrico das plantas, induzindo estresse oxidativo e prejudicando as trocas gasosas e a eficiência fotossintética com consequente diminuição da homeostase nutricional e do crescimento das plantas em ambos os períodos de duração. A aplicação de Si via fertirrigação e foliar foi eficiente e permitiu obter efeitos benéficos usando baixas doses do elemento. O fornecimento de Si via fertirrigação associado com a pulverização foliar apenas da fase de formação das mudas promoveu acúmulo suficiente para mitigar os efeitos causados pelo déficit hídrico por período de 7 até 60 dias após o transplantio, por meio da modulação do sistema antioxidante, favorecendo o metabolismo fisiológico, principalmente, na cana-de-açúcar. As aplicações de Si complementares após o transplantio causaram efeito benéfico em parâmetros fisiológicos e bioquímicos diminuindo os danos causados pelo déficit hídrico por período de 7 até 160 dias após o transplantio em ambas as espécies. O Si também modificou a relação C:N:P e aumentou a eficiência de uso de C, N e P em plantas de cana-de-açúcar e de cana-energia sob déficit hídrico por ambos os períodos. Espera-se que o Si seja amplamente utilizado nos sistemas de produção da cana-de-açúcar e da cana-energia para manter o suprimento global das necessidades de bioenergia presentes e futuras, mas com sustentabilidade hídrica.
The irrigated cultivation of sugarcane and energy cane has expanded in recent years. However, at the same time there has been an intensification of water restriction caused by climate change. Therefore, research focused on increasing the tolerance of these species of great agricultural interest, allowing the sustainable use of water, is essential. The supply of silicon (Si) can contribute to increase the efficiency of water use, mitigating the damage caused by the water deficit. But the effects of Si on the cultivation of sugarcane and energy cane plants under water deficit for 7 to 60 or 160 days after transplanting are not known. Furthermore, an improvement in the application technique is required. This research was carried out aiming to evaluate the effects of Si application via fertigation associated with foliar spraying on physiological, biochemical and nutritional parameters in sugarcane and energy cane plants cultivated under severe water deficit for two periods of duration. Four experiments were carried out in a controlled condition. Initially, the effect of fertigation associated with Si foliar spraying applied only in the seedling formation phase in sugarcane (experiment I) and energy cane (experiment II) plants cultivated under severe water deficit for a period was evaluated 7 to 60 days after transplantation. Subsequently, the effect of Si was evaluated in the same modes of application in the seedling stage and with complement after transplanting in sugarcane (experiment III) and energy cane (experiment IV) plants cultivated under severe water deficit for a period of 7 to 160 days after transplantation. The severe water deficit reduced the water content and water potential of plants, inducing oxidative stress and impairing gas exchange and photosynthetic efficiency, with a consequent decrease in nutritional homeostasis and plant growth in both duration periods. The application of Si via fertigation and foliar was efficient and allowed to obtain beneficial effects using low doses of the element. The Si supply via fertigation associated with foliar spraying only during the seedling formation phase promoted sufficient accumulation to mitigate the effects caused by the water deficit for a period of 7 to 60 days after transplantation, through the modulation of the antioxidant system, favoring the physiological metabolism, mainly in sugarcane. Complementary Si applications after transplanting had a beneficial effect on physiological and biochemical parameters, reducing damage caused by water deficit for a period of 7 to 160 days after transplantation in both species. Si also modified the C:N:P ratio and increased the efficiency of C, N and P use in sugarcane and energy cane plants under water deficit for both periods. Si is expected to be widely used in sugarcane and energy cane production systems to maintain global supply of present and future bioenergy needs, but with water sustainability.
The irrigated cultivation of sugarcane and energy cane has expanded in recent years. However, at the same time there has been an intensification of water restriction caused by climate change. Therefore, research focused on increasing the tolerance of these species of great agricultural interest, allowing the sustainable use of water, is essential. The supply of silicon (Si) can contribute to increase the efficiency of water use, mitigating the damage caused by the water deficit. But the effects of Si on the cultivation of sugarcane and energy cane plants under water deficit for 7 to 60 or 160 days after transplanting are not known. Furthermore, an improvement in the application technique is required. This research was carried out aiming to evaluate the effects of Si application via fertigation associated with foliar spraying on physiological, biochemical and nutritional parameters in sugarcane and energy cane plants cultivated under severe water deficit for two periods of duration. Four experiments were carried out in a controlled condition. Initially, the effect of fertigation associated with Si foliar spraying applied only in the seedling formation phase in sugarcane (experiment I) and energy cane (experiment II) plants cultivated under severe water deficit for a period was evaluated 7 to 60 days after transplantation. Subsequently, the effect of Si was evaluated in the same modes of application in the seedling stage and with complement after transplanting in sugarcane (experiment III) and energy cane (experiment IV) plants cultivated under severe water deficit for a period of 7 to 160 days after transplantation. The severe water deficit reduced the water content and water potential of plants, inducing oxidative stress and impairing gas exchange and photosynthetic efficiency, with a consequent decrease in nutritional homeostasis and plant growth in both duration periods. The application of Si via fertigation and foliar was efficient and allowed to obtain beneficial effects using low doses of the element. The Si supply via fertigation associated with foliar spraying only during the seedling formation phase promoted sufficient accumulation to mitigate the effects caused by the water deficit for a period of 7 to 60 days after transplantation, through the modulation of the antioxidant system, favoring the physiological metabolism, mainly in sugarcane. Complementary Si applications after transplanting had a beneficial effect on physiological and biochemical parameters, reducing damage caused by water deficit for a period of 7 to 160 days after transplantation in both species. Si also modified the C:N:P ratio and increased the efficiency of C, N and P use in sugarcane and energy cane plants under water deficit for both periods. Si is expected to be widely used in sugarcane and energy cane production systems to maintain global supply of present and future bioenergy needs, but with water sustainability.
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Palavras-chave
Plantas Nutrição, Cana-de-açúcar, Água Uso, Irrigação com águas residuais