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Nitrogen Fertilization and Rhizobial Inoculation Effects on Kura Clover Growth
Author(s) -
Seguin Philippe,
Sheaffer Craig C.,
Ehlke Nancy J.,
Russelle Michael P.,
Graham Peter H.
Publication year - 2001
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/agronj2001.1262
Subject(s) - agronomy , seeding , rhizobia , human fertilization , loam , inoculation , microbial inoculant , biology , dry matter , fertilizer , nitrogen fixation , horticulture , soil water , bacteria , ecology , genetics
Kura clover ( Trifolium ambiguum M.B.) is a persistent, rhizomatous forage legume; however, its use is currently limited by slow establishment. We determined the effects of rhizobial inoculation and N fertilization on kura clover growth and N 2 fixation in the seeding year. Kura clover was seeded with or without a commercial rhizobial inoculant and with and without N fertilization in three environments. Fertilization treatments consisted of 100 kg N ha −1 either applied at seeding or split in 10 kg N ha −1 applications every other week after seeding. Nitrogen fertilization increased seeding‐year herbage accumulation in all locations, but the response to fertilizer N was greater on a loamy sand with low organic matter and available N than on a silt loam with high soil organic matter. Rhizobial inoculation failed to consistently improve seeding‐year herbage accumulation compared with no inoculation; a positive response was observed in only one of three environments. Dry matter accumulation responses of root and rhizome to N fertilization and rhizobial inoculation were similar to that of herbage. Dinitrogen fixation in the seeding year varied between 9 and 25 kg ha −1 fixed N, depending on the environment. Seeding‐year inoculation increased postseeding year herbage yield. Also, when a positive response to N fertilization occurred in the seeding year, the response was maintained in the postseeding year. A commercial rhizobial inoculant was ineffective in establishing adequate nodulation in the seeding year in a N‐limited soil, indicating the need to identify more effective rhizobia for kura clover.