Nitrogen Fertilization and Rhizobial Inoculation Effects on Kura Clover Growth
- Philippe Seguina,
- Craig C. Sheaffer *b,
- Nancy J. Ehlkeb,
- Michael P. Russellec and
- Peter H. Grahamc
- a Dep. of Plant Sci., McGill Univ., Macdonald Campus, 21111 Lakeshore Rd., Sainte Anne-de-Bellevue, QC, Canada H9X 3V9
b Dep. of Agron. and Plant Genet., Univ. of Minnesota, 1991 Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108-6026
c Dep. of Soil, Water, and Climate, Univ. of Minnesota, 1991 Buford Circle, St. Paul, MN 55108-6028
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 N2 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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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