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Agronomy Journal Abstract -

Effect of Potassium Fertilizers on Malting Barley Infected with Common Root Rot1


This article in AJ

  1. Vol. 78 No. 1, p. 197-200
    Received: Mar 18, 1985

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  1. C. A. Timm,
  2. R. J. Goos,
  3. B. E. Johnson,
  4. F. J. Sobolik and
  5. R. W. Stack2



Malting barley (Hordeum vulgare L.) in North Dakota has a history of yield and quality responses to small additions of KCl fertilizer on soils with ample native supplies of exchangeable potassium (K). Five field experiments were established in central or western North Dakota in 1983 to determine if a chloride (Cl)-induced repression of common root rot, incited by Cochliobulus sativus, was a possible explanation for these past responses. The soils were fine loamy Haploborolls, Argiborolls, or Haplaquolls with greater than 800 kg K ha−1 exchangeable K in the plow layer. Experimental design was a factorial combination of two K rates, 23 and 94 kg K ha−1, by two K sources, KCl and K2SO4, plus a control treatment. A randomized complete block design with five or six replicates was employed. Fertilization with KCl significantly decreased root rot incidence at the boot stage at two of five sites and significantly decreased disease severity at the dough stage at three of the five sites. The high rate of KCl visually reduced the severity of spot blotch symptoms on the flag leaves at one site. Nitrate concentrations in plant foliage tended to be depressed at the highest rate of KCl. Chloride concentrations in plant foliage were dramatically increased by KCl application, although concentrations of Cl in control treatments appeared adequate enough to preclude an actual Cl nutritional deficiency. Grain yields were significantly increased by the high rate of KCl at one site. Fertilization with K2SO4 significantly increased disease severity at two sites but otherwise had no effect on disease incidence, severity, or grain yield. This research substantiated that Cl-induced disease repression may explain the history of KCl response in North Dakota, but the reason for this effect is not known.

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