The response of corn to flooding and soil moisture stress

Date

1987

Abstract

The yield response of corn (IPB Var. 1) to flooding of various durations at different stages of growth was studied using size 16 earthen pots. The same at different water table depths and various other soil moisture treatments were also studied using the drainage-type lysimeters at the Land and Water Resources Engineering Experimental Farm of UPLB. The optimum soil moisture condition and crop coefficients at various stages of growth were also determined from the lysimeter experiment. Thirty (30) days after seeding (DAS) was found more sensitive to flooding than 15 DAYS, 45 DAS, and 60 DAS growth stages. Yield reduction of corn was more associated with the growth stage than duration of flood. Also, the longer durations of floods were more harmful if they occurred during earlier stages. For a given duration of flooding, there were no significant differences in the 1000 grain weight and dry matter content as a result of flooding at various stages of growth. However, for a given growth stage, longer flood durations resulted in lower 1000 grain weight and dry matter content. Except for the 30 DAS treatment, no significant differences in plant height were observed in all growth stages. In all growth stages flooding of varying durations did not result in significant change in plant height. The yield response equation of corn to flooding was expressed as Y=Yp (SI/SIc)^b where, Y is the predicted yield, Yp is the potential yield, SI is the stress index or the flood duration in days and b is the slope or susceptibility factor. A set of curves was also developed after the mathematical analyses of yield data and it shows relationships among relative grain yield flood duration and growth stage of corn. From the lysimeter experiment, the highest yield was obtained in the 70 cm water table depth treatment. The soil moisture tension ranged from 3 bars (50% available moisture depletion) at root zone depth of 30 cm o 1/3 bar (field capacity) at depth of 60 cm. Analysis of grain yield was done with respect to stress index which was expressed as the ratio of total water use (AET) to the potential evapotranspiration(PET). The highest yield was obtained when the AET/PET ratio was about 0.80. The crop coefficients for various stages of crop growth were computed from actual water use at the 70 cm water table depth, since this depth resulted in the highest yield. The values ranged from 0.38 to 1.05. The higher values of crop coefficient were noted during 8th and 9th weeks period (50 DAS-63 DAS). This study strongly recommends that the irrigation of corn field should be based on the soil moisture depletion, which largely depends upon the evaporative demand of

Document Type

Master Thesis

Language

English

LC Subject

Corn

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 995 1987 A2 S52

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