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Accumulation and Distribution of K, Ca, and Mg by Selected Determinate Soybean Cultivars Grown With and Without Irrigation 1
Author(s) -
Karlen D. L.,
Hunt P. G.,
Matheny T. A.
Publication year - 1982
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1982.00021962007400020021x
Subject(s) - loam , irrigation , growing season , cultivar , agronomy , point of delivery , nutrient , dry matter , soil water , tonne , biology , horticulture , zoology , chemistry , ecology , organic chemistry
Reports on nutrient accumulation and distribution by determinate soybeans [ Glycine max. (L.) Merr.] when grown under field conditions have seldom compared irrigated and nonirrigated management or attempted to measure differences among cultivars. To provide this information we grew three or four determinate soybean cultivars from Maturity Group VI, VII, or VIII with or without irrigation on a Norfolk loamy sand (fine‐loamy, siliceous, thermic Typic Paleudults) during 1978 and 1979. Plant samples were collected periodically throughout the growing season to measure dry matter accumulation and distribution among the leaves, petioles, stems, and pods. Plant fractions were analyzed for K, Ca, and Mg to measure nutrient accumulation and distribution. The two growing seasons during which the soybeans were grown had distinctly different rainfall patterns. In 1978 a drought existed for most of the reproductive growth period, while in 1979 a drought occurred during the vegetative growth stages. Also, in 1979 the soil water content below 30 cm was generally higher throughout the entire growing season. Potassium, Ca, and Mg concentrations and accumulations were all greater during 1979, but even with irrigation, yields averaged only 1.95 metric tons/ha compared to irrigated yields of 3.16 metric tons/ha in 1978. Nonirrigated yields averaged 1.72 and 1.62 metric tons/ha in 1978 and 1979. The lower yields in 1979 may have been caused by very wet soils following Hurricane David which may have reduced O 2 levels during pod fill. The uptake patterns of K, Ca, and Mg showed different responses to water stress, probably because of differences in the mechanism by which these nutrients move to plant roots. Potassium uptake under nonirrigated (stressed) conditions fluctuated with water availability, whereas K uptake under nonstressed (irrigated) conditions was relatively constant until physiological maturity. Calcium and Mg uptake were relatively constant regardless of stress until physiological maturity. Differences in nutrient concentrations and accumulations among cultivars were generally not statistically significant, although the Ransom cultivar frequently had the highest nutrient concentrations and also produced the highest seed yield. Irrigation did not significantly change the cation concentrations within the soybean plant. Therefore, differences in cation accumulation were primarily caused by increased plant growth.