Irrigation Effects on Vegetative and Reproductive Development of Three Soybean Cultivars1
- D. A. Ashley and
- W. J. Ethridge2
Previous investigations have demonstrated a response in soybean [Glycine max (L.) Merr.] yields to supplemental water applications during reproductive development, but few have described the effects of irrigation during different development periods on fruiting patterns and vegetative development in relation to yields. Variables included in this field experiment were four moisture regimes — unirrigated, full season irrigation, irrigation begun at bloom stage, and irrigation begun at pod fill stage — and three cultivars, ‘Ransom’, ‘Hamptom 266A’, and ‘Coker 102’. Data were collected for seed yield, pod number and dry weight, dry weight of vegetative components during reproductive development and seasonal soil moisture status. The soil was a sandy loam (Rhodic Paleudult, clayey, kaolinitic, thermic family). Full season and bloom stage irrigation treatments produced higher yields than the unirrigated check except for Hamptom 266A in 1974. Yields from plants receiving the podfill stage irrigation treatment were higher than the unirrigated check in drier seasons of 1972 and 1973 but not in 1974. Irrigation beginning at pod fill produced yields equal to the full season and bloom stage treatments in some cases and somewhat lower yields in other cases. Higher yields and greater response to irrigation was obtained from shorter, less vegetative Ransom plants than the other two cultivars. Water applications prior to blooming greatly increased vegetative dry weight, and number as well as dry weight of pods. Beginning irrigation during reproductive development had little effect on vegetative dry weight, but usually resulted in a greater number of pods late in the season than the unirrigated check.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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