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Crop Science Abstract -

Forage Yield and Nitrogen Partitioning Responses of Alfalfa to Two Cutting Regimes and Three Soil Nitrogen Regimes1


This article in CS

  1. Vol. 27 No. 5, p. 909-914
    Received: Oct 30, 1986

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  1. M. W. Trimble,
  2. D. K. Barnes,
  3. G. H. Heichel and
  4. C. C. Sheafter2



Plant breeders need to thoughtfully select appropriate crop management systems for the evaluation of alfalfa (Medicago sativa L.) populations. The objective of this study was to determine if genotype ✕ treatment interactions were associated with frequency of cutting and soil N concentrations. Twenty-eight alfalfa populations representing four winterhardy germplasm sources were evaluated in six treatments using hill plots at three Minnesota locations. The six treatments consisted of three soil N regimes, referred to as high, ambient, and low (approximately 200, 20, and 10 kg NO3/ha, respectively) and each tested over three and four-cut regimes. The experimental design was a randomized complete block with a split-plot treatment arrangement. Whole plots were the six treatments Subplots were the 28 populations. Measurements included herbage, crown, and root yield; plant number per plot; winter injury; nodule mass; root disease; tap root size; and N concentratin in the herbage, crowns, and and roots. The high soil N regime reduced nodulation and increased herbage yield during the establishment year, indicating that plant available N was limiting herbage production in the ambient N and low N regimes. The high soil N increased N concentration in the herbage, crowns and roots, but did not change the N proportion in those palnt parts. The germplasm ✕ soil N regime interaction was not significantly for herbage yield, but it was significant for total root and lateral root yield. Cutting regime affected all measurements except tap root size. Significant germplasm ✕ cutting regime interactions were observed for herbage and root yield, winter injury, and tap root size. Germplasms differed in their ability to partition biomass to herbage and to roots. The results suggested that crop management systems must be chosen carefully because they can affect the rank in performance among alfalfa populations for many agronomic traits.

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Copyright © 1987. Crop Science Society of America, Inc.Copyright © 1987 by the Crop Science Society of America, Inc.