Avaliação de duas cultivares de cana-de-açúcar submetidas a diferentes lâminas de irrigação por gotejamento subsuperficial, no noroeste paulista
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Data
2015-12-17
Autores
Silva Júnior, Hélio Moreira da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Um dos principais problemas que limita a produtividade e a longevidade dos canaviais brasileiros são as restrições climáticas, principalmente devido à distribuição irregular das chuvas ao longo do ano. Tal problema pode ser minimizado com o uso da irrigação, no entanto, há necessidade de se determinar criteriosamente a lâmina de máxima eficiência. O presente trabalho teve por objetivo avaliar o crescimento e os componentes de produção de duas cultivares de cana-de-açúcar, submetidas a diferentes lâminas de irrigação, em três ciclos de cultivo. O delineamento experimental utilizado foi em blocos casualizados com arranjo fatorial (2 x 6), sendo duas cultivares de cana-de-açúcar (RB92579 e RB855453) e seis lâminas de irrigação (testemunha, 50%, 75%, 100%, 125%, 150% da evapotranspiração da cultura, ETc), com quatro repetições. Durante a condução do experimento foram obtidas as seguintes variáveis, a cada quatro meses: perfilhamento; altura de plantas; índice de área foliar (IAF); comprimento, largura e número das folhas; área foliar. As cultivares RB855453 e RB92579 responderam às lâminas de irrigação. Quanto à matéria seca, a RB92579 apresentou resultados semelhantes em todos as lâminas avaliadas, enquanto a RB855453 apresentou melhor resultado entre as lâminas 100 e 150% da ETc. Para acúmulo de açúcar por ha a cultivar RB855453 foi superior à RB92579, quando irrigada. Para ATR, a cultivar RB92579 obteve melhores resultados nas lâminas: testemunha, 75, 100 e 125% ETc. Já a cultivar RB855453 obteve melhores valores de ATR nas lâminas: testemunha e 125% ETc e redução em 75% da ETc. Como a comercialização da cana é por R$.t-1 ou por ATR, a cultivar RB92579 foi a mais rentável na lâmina com 125% da ETc, que se mostrou a mais produtiva para TCH e ATR. A cultivar RB855453 caracterizou-se como grande produtora de matéria fresca e também de açúcar, especialmente na lâmina 125% da ETc.
One of the main problems that reduces productivity and longevity of Brazilian sugarcane are the climatic constraints, mainly due to the irregular distribution of rainfall during the year. Such problem can be minimized with the use of irrigation, however, it is necessary to estimate criteriously the water depth of maximum eficiency. The present study aimed to evaluate the growth and production components of two cultivars of sugarcane, subjected to different water depths in three growing cycles. The experimental design was randomized in blocks with factorial arrangement (2 x 6), given by two varieties of sugar cane (RB92579 and RB855453), six irrigation depths (testify, 50%, 75%, 100%, 125%, 150% of the crop evapotranspiration, ETc), and with four repetitions. During the experiment the following variables were evaluated, every four months: tillering; plants height; leaf area index (LAI); length, width and number of leaves; leaf area. The varieties RB855453 and RB92579 responded to water depths. About the amount of dry matter, the RB92579 presented similar results in all the water depths evaluated, while RB855453 showed better results with water depths between 100 and 150% of ETc. The variety RB855453 showed higher values than RB92579 for accumulation of sugar per area, when irrigated. For ATR, the RB92579 obtained the best results in growing on the treatments: testify, 75, 100 and 125 of ETc. The variety RB855453 obtained the ATR best values with testify and 125% ETc and the worst value with 75% ETc. Once the sugarcane marketing is given by R$ t-1 or for ATR, the variety RB92579 was the most profitable with the depth 125% ETc, showing the highest values of TCH and ATR. The variety RB855453 was characterized and classified as a great producer of fresh matter and sugar with the treatment 125% of ETc.
One of the main problems that reduces productivity and longevity of Brazilian sugarcane are the climatic constraints, mainly due to the irregular distribution of rainfall during the year. Such problem can be minimized with the use of irrigation, however, it is necessary to estimate criteriously the water depth of maximum eficiency. The present study aimed to evaluate the growth and production components of two cultivars of sugarcane, subjected to different water depths in three growing cycles. The experimental design was randomized in blocks with factorial arrangement (2 x 6), given by two varieties of sugar cane (RB92579 and RB855453), six irrigation depths (testify, 50%, 75%, 100%, 125%, 150% of the crop evapotranspiration, ETc), and with four repetitions. During the experiment the following variables were evaluated, every four months: tillering; plants height; leaf area index (LAI); length, width and number of leaves; leaf area. The varieties RB855453 and RB92579 responded to water depths. About the amount of dry matter, the RB92579 presented similar results in all the water depths evaluated, while RB855453 showed better results with water depths between 100 and 150% of ETc. The variety RB855453 showed higher values than RB92579 for accumulation of sugar per area, when irrigated. For ATR, the RB92579 obtained the best results in growing on the treatments: testify, 75, 100 and 125 of ETc. The variety RB855453 obtained the ATR best values with testify and 125% ETc and the worst value with 75% ETc. Once the sugarcane marketing is given by R$ t-1 or for ATR, the variety RB92579 was the most profitable with the depth 125% ETc, showing the highest values of TCH and ATR. The variety RB855453 was characterized and classified as a great producer of fresh matter and sugar with the treatment 125% of ETc.
Descrição
Palavras-chave
Evapotranspiração, Sacarum spp., Bioenergia, Produtividade, Irrigação