Terminal infiltration rates under sagebrush canopies were about 35% higher than interspace areas at 3 study sites in northern New Mexico. Differences in infiltration rates among strata may largely be attributed to a greater amount of litter yield and basal cover, and 2 to 3 times higher percentage of organic carbon under the canopy of sagebrush compared to the interspace. Infltration rates and sediment concentration of runoff within the canopy zone and interspace areas were not affected chemical control treatments. Total sediment production was about 29 to 41% higher under the canopy of tebuthiuron treated sagebrush compared to the canopy zone of untreated rangeland. However, these differences were not consistent and were significant at only 1 study site. Total sediment production was related primarily to a combination of soil texture, sagebrush canopy cover, and total vegetation production. Authors are former graduate research assistant and associate professors, Department of Animal and Range Sciences, New Mexico State University, Las Cruces 88001. Received for publication as journal article no. 1 143 from the New Mexico Agricultural Experiment Station. Manuscript accepted 25 July 1985. Sagebrush (Artemisia tridentata) is an aromatic, evergreen shrub growing on an estimated 2.2 million ha of rangeland in northern New Mexico and an additional 37 million ha in the western United States (Berry 1979). Approximately 70% of the sagebrush-dominated rangelands in New Mexico are degraded and produce less forage than their potential (McDaniel and Garrison 1982). Reasons often given to justify renovation of the sagebrush rangelands include the need to increase forage for wildlife and livestock, and to reduce soil degradation (Scifres 1980). Herbicide applications are an accepted tool to improve sagebrush rangelands, but have not been widely used in New Mexico. Control of sagebrush with 2,4-D [(2,4-dichlorophenoxy) acetic acid] at rates of 2.2 kg acid equivalence/ ha, while reported elsewhere as successful in killing sagebrush (Elwell and Cox 1950, Hull and Vaughan 1951, Hyder 1953, Evans et al. 1979, among others), has not been successfully employed in New Mexico (McDaniel and Balliette 1984). Three years of repeated spray trials with 2,4-D at 2.2. kg a.e./ ha did not kill more than 50%O of Wyoming (A.t. var. 160 JOURNAL OF RANGE MANAGEMENT 39(2), March 1986 This content downloaded from 207.46.13.150 on Thu, 28 Jul 2016 04:32:40 UTC All use subject to http://about.jstor.org/terms wyomenisis) or mountain (A.t. var. vaseyana) sagebrush in northern New Mexico (Balliette 1984). Tebuthiuron (N{5-(l,l -dimethylethyl)1,3,4-thiadiazol-2-yl]-N,N'dimethylurea) at 0.56 kg active ingredient/ha offers significant promise for sagebrush control in New Mexico. Date of application or phenological stage of sagebrush growth does not limit tebuthiuron activity, and the herbicide usually kills more than 80% of the plants (McDaniel and Balliette 1984). Similar levels of sagebrush control following tebuthiuron treatments have been reported in Oregon and Wyoming (Britton and Sneva 1984, Whitson and Alley 1984). Increased forage production is a primary reason to control sagebrush with herbicides. Reduction of soil erosion is often given as an additional benefit; however, little information exists for New Mexico rangelands about the impact of sagebrush control on infiltration rates and sediment production. Sagebrush rangelands in poor condition lose considerable amounts of soil by wind and water erosion (Rosa and Tigerman 1951, Tisdale et al. 1969, and Blackburn 1973). Management and control of sagebrush can increase cover and yield of herbaceous species and reverse the soil degradation that has occurred over the past century (Young et al. 1980). Our primary objective was to determine the short-term impact on infiltration rates, sediment concentration of runoff, and total sediment production from sagebrush rangelands treated with herbicides. A secondary objective was to identify vegetation and soil characteristics related to these watershed parameters.