Flurprimidol effects on Kentucky bluegrass under reduced irradiance

• Published in: Crop science 1999-09, Vol.39 (5), p.1423-1430
• Main Authors: Stier, J.C, Rogers, J.N. III, Crum, J.R, Rieke, P.E
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Analysis; application rate; athletic fields; Biological and medical sciences; Cropping systems. Cultivation. Soil tillage; flurprimidol; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Grasses; growth; growth rate; height; Light; light intensity; lighting; phytotoxicity; plant characteristics; Plant growth; Poa pratensis; quality; root systems; rooting; roots; shade; shear strength; shoots; soccer; Tending. Growth control; Tillage. Tending. Growth control; tillering; traffic; Turf; Turf management; Turfgrasses
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci1999.3951423x

Turf management in shaded conditions is difficult in part because the reduced irradiance causes excessive shoot elongation, reduced tillering and root growth, and weak plants exceptionally prone to damage. Successful installation of natural grass athletic fields in covered or shaded stadia require improved management procedures. The objective of this study was to determine if flurprimidol [alpha-(1- = -methylethyl)-alpha-[(trifluourmethoxy)phenyl]- 5-pyrimidinemethanol], a gibberellic acid (GA)-biosynthesis inhibitor, could be used to increase turf quality for athletic fields in covered stadia and other reduced irradiance situations. Portable plots of Kentucky bluegrass (Poa pratensis L.) were established outdoors and moved inside a covered stadium simulator facility (CSSF). Four rates of flurprimidol (0.56, 1.12, 1.68, and 2.80 kg ha(-1)) were compared against a control. Studies were conducted under ambient (equivalent to 2-3% full summer sunlight) and supplemental (equivalent to 9-18% full summer sunlight) irradiance. The turf was evaluated with and without simulated soccer traffic. Under ambient irradiance conditions, turf quality generally declined to unacceptable levels within 30 d, although the low rate of flurprimidol extended this period for up to 60 d. Supplemental irradiance provided turf of acceptable quality for up to 70 d and the low rate of flurprimidol extended this period for >100 d. Applications repeated within 30 to 40 d virtually stopped measurable shoot growth under all irradiance and traffic regimes. Flurprimidol did not affect turf shear resistance or rooting but did increase tillering. Low rates of flurprimidol should be useful for maintaining turf in reduced irradiance conditions because turf quality is enhanced with minimal risk of phytotoxicity.