Responses of flue-cured tobacco to moisture regimes.

Date

1985

Abstract

Twenty-four drainage-type lysimeters at the Central Experiment Station of UPLB were used to determine the water requirements of flue-cured tobacco and to develop equations describing the relationships between yield, nicotine, and reducing sugar and the ratio of the actual over the potential evapotranspiration (Ea/Ep). The treatments, replicated three times, consisted of all combinations of irrigating and not irrigating the crop at three growth stages. The amount of weekly irrigation was the Ep during the preceeding week as estimated using Penman equation. The crop coefficient, kc, is the level of Ea/Ep which gives the optimum yield quantity and quality. Its values were found to be 0.4, 0.8 and 0.7 at the first, second, and third growth stages, respectively. The yield of Coker 254 was a quadratic function of Ea/Ep during the growing season. Maximum yield was achieved when Ea/Ep=0.79. Stepwise regression showed that the critical period of irrigation was from 33 to 67 DAT. The nicotine contents of the 5th, 10th, and 15th leaves increased with decreasing Ea/Ep while the reducing sugar contents and the reducing sugar-nicotine ratio increased with increasing Ea/Ep. The best results, in terms of high yield, low nicotine, high reducing sugar, and desirable reducing sugar-nicotine ratio was achieved at an Ea/Ep ranging from 0.7 to 0.8.

Document Type

Master Thesis

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 995 1985 A2 J38

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