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Nitrogen Partitioning in Cowpea as Influenced by Rhizobial Strain and Mineral Nitrogen
Author(s) -
Luyindula N.,
Weaver R. W.
Publication year - 1989
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/agronj1989.00021962008100040009x
Subject(s) - rhizobia , vigna , nitrogen fixation , bradyrhizobium , nitrogenase , inoculation , biology , nitrogen , agronomy , nitrate , strain (injury) , starter , azotobacter chroococcum , horticulture , chemistry , rhizobium , food science , ecology , organic chemistry , anatomy
Partitioning of nitrogen into the pods of legumes is an important yield determinant. The ability of cowpea [ Vigna unguiculata (L.) Walp.] ‘Bush Purple Hull’ to partition N from dinitrogen fixation and assimilated nitrate into pods was measured with the aid of 15 N. Cowpea was inoculated with four strains of Bradyrhizobium species and grown in a glasshouse to maturity. Two nitrate treatments were included; one provided an initial dose of starter N (40 mg plant −1 ) and the other provided split applications of N throughout the growth period (total of 240 mg plant −1 ). With starter N only, the results indicated that the strain of rhizobia did not influence partitioning of biologically fixed dinitrogen or nitrate N into pods. However when inoculated with either of two strains, cowpea partitioned approximately 63% of the total assimilated nitrate from the continuous N treatment into the pods, whereas another strain partitioned approximately 52% into pods. Of the total N from dinitrogen fixation, 53 and 58% was partitioned into the pods for the starter N and continuous N treatments respectively. The strains of rhizobia were similar in the quantity of nodule tissue formed on the roots, but the quantity of N contained in the nodule tissue varied from 40 to 20 mg N plant −1 for the starter N treatment. It appears that strains of rhizobia should be considered when undertaking experiments involving N partitioning.