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Critical Levels of Sulfur in Bur Clover 1
Author(s) -
Jones M. B.,
Ruckman J. E.,
Lawler P. W.
Publication year - 1972
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/agronj1972.00021962006400010018x
Subject(s) - sulfur , legume , dry matter , nutrient , grassland , red clover , agronomy , biology , organic matter , botany , horticulture , chemistry , ecology , organic chemistry
Sulfur deficiencies are widespread in areas of California annual grassland where bur clover ( Medicago hispida ) is an important legume. The growth of this species is greatly increased by applications of S where S is deficient. The purpose of this study was to obtain information useful in assessing the sulfur status of annual grasslands in which bur clover occurred. The clover was grown in nutrient solution with varying levels of available S. Total S and SO 4 ‐S concentrations in immature and mature leaves and in middle and lower stems were studied in relation to dry matter production. The concentration of total S where yields were 95% of maximum (“critical concentrations”) was 0.225% for both immature and mature leaf blades and was 0.080% for middle and lower stems. The “critical concentrations” for SO 4 −S were 160, 140, 100, and 160 ppm for immature and mature leaves and middle and lower stems, respectively. Organic S (total S minus SO 4 −S) reached a maximum at about 0.250% in leaves and about 0.100% in the stems. Where S was applied in luxury amounts unmetabolized sulfur accumulated as SO 4 −S. Highest concentrations were found in the lower stems, lesser amounts in the upper stems, and least SO 4 −S was found in the leaves.