• Comparative Growth Stages and Plant Parts for Critical Nitrate-N Concentration of Squirreltail

      Hylton, L. O.; Ulrich, A. (Society for Range Management, 1969-05-01)
      The critical nitrate-N concentration for growth of squirreltail, Sitanion hystrix (Nutt.) J. G. Smith, was not appreciably affected by plant maturity when recently-matured blades rather than entire shoots were analyzed for nitrate-N. The critical nitrate-N concentrations for recently-matured blades were, respectively, 400, 500, and 500 ppm nitrate-N, dry basis, for the early vegetative, late vegetative, and late-boot growth stages. In contrast, the critical nitrate-N concentrations for shoots were 400, 600, and 1300 ppm, respectively, for the same growth stages. Recently-matured blades should, therefore, be collected to determine the N status of squirreltail in the field at any active growth stage. A high N status increased top growth preferentially to root growth. Hence, the ratio of tops to roots increased from 1.0 to 3.0, for N deficient and N sufficient plants, respectively.
    • Critical Nitrate-N Concentrations for Growth of Two Strains of Idaho Fescue

      Hylton, L. O.; Ulrich, A. (Society for Range Management, 1968-09-01)
      Nitrate-N in shoots of different strains of Idaho fescue, Festuca idahoensis, can be used for an adequate diagnosis of their respective N statuses at the late vegetative growth stage. The suggested critical nitrate-N concentration for growth of Elmer Idaho fescue, the improved strain used in this study, is 500 ppm of nitrate-N in the shoots, dry basis. The suggested critical nitrate-N concentration for growth of the nonimproved strain is 140 ppm of nitrate-N, dry basis. These critical concentrations are guides that can be used to determine the N status of Idaho fescue on rangelands. Nitrate-N in shoots of Idaho fescue should be above 500 ppm, dry basis, during active vegetative growth, if maximum forage production is desirable.
    • Sulfur Needs of Spanish Clover and the Relation of Sulfur to Other Nutrients as Diagnosed by Plant Analysis

      Hylton, L. O.; Cornelius, D. R.; Ulrich, A. (Society for Range Management, 1968-05-01)
      Sulfur needs of Spanish clover, Lotus purshianus (Benth.) Clements and Clements, were determined by plant analysis in a nutrient solution study. Top growth was affected more than root growth by changes in S supply. Protein synthesis in the shoots was affected little by S deficiency. Sulfate-S was better than organic-S or total-S to diagnose the S status of the plant adequately. The critical sulfate-S concentration for growth of the plant is about 100 ppm, dry basis, in the middle stem section of the shoots.