Controlling Shrubs in the Arid Southwest with Tebuthiuron
1985; University of Arizona; Volume: 38; Issue: 5 Linguagem: Inglês
10.2307/3899705
ISSN2162-2728
AutoresCarlton H. Herbel, Howard L. Morton, Robert P. Gibbens,
Tópico(s)Plant and fungal interactions
ResumoVarious rates of tebuthiuron pellets were aerially applied on rangelands in the Southwest to determine effects on noxious shrubs. Creosotebush (Larrea tridentata) and tarbush (Flourensia cernua) shrubs were controlled with 0.4 and 0.3 kg active ingredient (a.i.)/ha, respectively, of tebuthiuron pellets. About 1.1 kg a.i./ha of tebuthiuron pellets controlled honey mesquite (Prosopis glandulosa) growing on loamy sands or sandy loams. About 0.6 and 0.5 kg a.i./ha of tebuthiuron pellets controlled whitethorn acacia (Acacia constricta) and desert zinnia (Zinnia pumila), resptctively. Higher rates of tebuthiuron are needed to control those shrubs on deep, fine textured soils than on shallow, coarse textured soils. Woody plants have rapidly invaded new areas in the Southwest (Buffington and Herbel 1965, York and Dick-Peddie 1969). Some woody plants are responsible for reduced forage production and have other adverse effects on livestock operations (Herbel et al. 1983). Dense stands have harmful effects on the environment because of accelerated wind or water erosion in arid areas (Gould 1982). It is estimated that mesquite (Prosopis spp. L.) occurs on 37.7 mil ha, creosotebush (Larrea tridentata [DC.] Cov.) on 18.8 mil ha, and tarbush (Flourensia cernua DC.) occurs on 5.4 mil ha in the U.S. (Platt 1959). Various methods have been used to reduce the density and distribution of these plants (e.g., Fisher et al. 1959, Herbel and Gould 1970, Martin 1975, and Scifres 1977). Tebuthiuron [N-(5{ 1, 1 -dimethylethyl]l,3,4-thiadiazol-2-yl)-N,N'-dimethylurea] is effective for chemical control of many woody plants. In Texas, it killed 80, 70, and 86%, respectively, of live oak (Quercus virginiana Mill.), whitebrush (Aloysia lycioides Cham.), and sand shinnery oak (Q. havardii Rydb.) at 1.1 kg active ingredient (a.i.)/ ha; and 45 and 60% of Macartney rose (Rosa bracteata Wendl.) and blackbrush acacia (Acacia rigidula Benth.), respecAuthors are range scientist, P.O. Box 3JER, Las Cruces, N. Mex. 88003; plant physiologist, Tucson, Ariz.; and range scientist. Las Cruces, Agr. Res. Serv. U.S. Dep. Agr. Cooperative investigations of Agr. Res. Serv., U.S. Dep. Agr., and N. Mex. Agr. Exp. Sta. Mention of trade names or proprietary products does not constitute endorsement by the USDA and does not imply its approval to the exclusion of other products that may be suitable. This paper is Journal Article No. 1066, Agr. Exp. Sta., N. Mex. State Univ.. Las Cruces 88003. Manuscript accepted February 1, 1985. tively, at 2.2 kg a.i./ha (Meyer and Bovey 1979, 1980a, and 1980b; and Jacoby and Meadors 1982). Meyer and Bovey (1979) reported 95, 50, and 85% of honey mesquite (Prosopis glandulosa Torr.) plants killed on a clay loam site in south central Texas with subsurface applications of the wettable powder of tebuthiuron at 9 kg a.i./ ha applied April 1973, April and December 1974, respectively. Jacoby et al. (1982) reported creosotebush kills of 86 and 91 % with applications of 0.5 and 0.7 kg a.i./ha of tebuthiuron on gravelly loams in the eastern portion of the Trans-Pecos area in Texas. Tarbush kills of 68 and 95% were obtained with the use of 0.5 and 0.8 kg a.i./ha of tebuthiuron on silty clay loams in the western part of the Edwards Plateau in Texas (Ueckert et al. 1982). Morton et al. (1978) reported that pelleted tebuthiuron treatments applied to a sandy loam soil in southern Arizona at rates of 0.56, 1.12, and 2.24 kg a.i./ha killed 77, 97, and 99% of creosotebush and 78, 100, and 1 00% of velvet mesquite (P. velutina Wooton) plants, respectively. This study determined effects of various rates of tebuthiuron on honey mesquite, cresotebush, tarbush, and other associated woody plants. Methods and Materials Six range areas werc treated with tebuthiuron in southern New Mexico and Arizona. A major part of the study was conducted on 2 sites on the Jornada Experimental Range, 35 km north of Las Cruces, N. Mex. Annual rainfall at the Jornada Headquarters averages 230 mm and the elevation is 1,260 m. One of the areas treated was a sandy range site dominated by mesquite. The soil is an Onite-Pintura complex (Bullock and Neher 1980). Onite is a coarse-loamy, mixed, thermic Typic Haplargid, and Pintura is a loamy, mixed, thermic Typic Torripsamment. The second treated area was a loamy range site dominated by creosotebush and tarbush. The soil is a Berino-Dona Ana association. They are both fine-loamy, mixed, thermic Typic Haplargids. Tebuthiuron pellets were aerially applied on 5-ha plots at various rates on each of the sites for 4 years, 1977-80 (see Tables I and 2 for actual rates). Applications were made in early summer each year. At treatment, mesquite leaves were mature and beans were ripening. Creosotebush was fruiting, while tarbush was in the leaf stage. Each plot was 62 X 800 m with an untreated area 12 m wide JOURNAL OF RANGE MANAGEMENT 38(5), September 1985 391 This content downloaded from 157.55.39.110 on Sat, 24 Sep 2016 05:51:42 UTC All use subject to http://about.jstor.org/terms Table 1. Mortality of honey mesquite 28 months after application of pelleted tebuthiuron on a sandy site on the Jornada Experimental
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