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

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.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.Migrated from OJS platform August 202