Desenvolvimento e produtividade da cana-de-açúcar em ambiente protegido sob diferentes níveis freáticos / Development and productivity of the sugarcane in greenhouse under different water table

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The aim of this work was to evaluate the effect of level and time of freatic elevation on variables related to plant growth, development, productivity and technological parameters of sugarcane crop. The experiment was carried out in a 120-m2 greenhouse, set up at the research station of the Rural Engineering Department Luiz de Queiroz College of Agriculture (ESALQ), São Paulo University. The experimental design was Randomized Complete Block with [(2x2x3)+1+2], totaling 15 treatments and 4 repetitions. The treatments constituted of: (a) elevation of the water table to 25 and 50 cm, (b) time of the water table elevation for 4, 6, 8 e 12 days, (c) stages of development 3, 6 and 9 months, and (d) constant water table of 40 and 60 cm during the cycle. There were in the experiment 60 concrete tubes with 0.40 m of internal diameter and 1.10 m of high, filled with Red-Yellow Alic Latosol. The following variables were analyzed: height of plant, tillering number, leaf area, length and diameter of stalks, productivity as well as technological parameters such as: BRIX, POL, FIBRE, AR and ATR. The analyses of sugarcane juice were performed in the laboratory of sugar and ethanol technology of ESALQ. The results obtained in growth analyses such as: tillering numbers, leaf area, height of plants, length and diameter of stalks, showed that the crop growth did not present significant differences between the applied treatments. The same was observed for the production of stalks and percentage of Brix. The most influenced technological parameter was the time of application of the treatments, except for the fiber percentage that was influenced by the water table and stage of development. The constant water table of 60 and 40 cm depth during caused larger ATR incomes. Growth parameters such as: tillering number, stalk diameter and plant height, did not presented significant differences between the treatments. Significant differences were only observed in length of stalks and foliar area for the T14 treatment, which presented the lowest averages. For the technological parameters, Brix, Pol and ATR, lower concentrations were observed when the treatments were applied in the end of the cycle. T15 treatment presented the largest ATR concentration differing significantly. The T15 treatment showed the lower concentration of reducing sugar (AR) and the highest concentration was observed for the T8 treatment, with no signficant differences for the other treatments. The highest fiber percentage was observed in treatment T1, differing significantly from the treatment T8, T12 and T13, with the lower fiber percentages. The production of sugar ratoon cane was bigger when applying the treatments in the end of the cycle (270 DAC), independent of the duration of the treatments. For the water table, the 40 cm of depth during all the culture cycle (T15) presented a reduction of 40% in relation to the sugarcane-plant, evidencing a possible reduction of crop cycles.

ASSUNTO(S)

ambiente protegido (plantas) cana-de-açúcar - produtividade water table technological parameters. desenvolvimento vegetal sacharum spp crescimento vegetal production lençóis freáticos.

ACESSO AO ARTIGO

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