Zoysiagrass establishment from sprigs following application of herbicides, nitrogen, and a biostimulator

Abstract

Sprigs of 'Meyer' zoysiagrass (Zoysia japonica Steud.) were treated with urea nitrogen, a biostimulator, and one of three preemergence herbicides or one of two postemergence herbicides to hasten establishment in two field studies. Monthly application of N at 48 kg · ha-1 during the growing season had no influence on sprig establishment the first year, but slightly increased (+5%) zoysiagrass cover the second year. Presoaking sprigs in a solution containing (mg · L-1) 173 aoxin and 81 cytokinin, and iron at 1.25 g · L-1 before broadcasting of sprigs, and biweekly sprays (g · ha-1) of 53 auxin and 24 cytokinin, and iron at 0.2 g · L-1 or (g · ha-1) 68 auxin and 36 cytokinin, and iron at 1.45 g · L-1 after broadcasting sprigs had no effect on zoysiagrass cover or rooting. Preemergence and postemergence herbicide use generally enhanced zoysiagrass cover by reducing smooth crabgrass competition [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl]. Oxadiazon enhanced zoysiagrass coverage more than dithiopyr, pendimethalin, quinclorac, or fenoxaprop. Oxadiazon and dithiopyr provided similar levels of crabgrass control, but dithiopyr reduced 'Meyer' zoysiagrass midsummer root growth. Chemical names used: 3,5,- pyridinedicarbothioic acid, 2-[difluromethyl]-4-[2-methyl-propyl]-6- (trifluoromethyl)S,S-dimethyl ester (dithlopyr); [±]-ethyl 2-[4-[(6-chloro- 2-benzoxazolyl)oxy]phenoxyl propanoate (fenoxaprop); 3-[2,4-dichloro-5-(1- methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); 3,7-dichloro-8-quin-olinecarboxylic acid (quinclorac).