Outcomes of net-present value analyses were projected for patterned applications of herbicide sprays and pellets to mixed brush in south Texas. Picloram + 2,4,5-T (1:1) were applied but 1987 costs of triclopyr + picloram sprays, currently registered and considered the biological equivalent treatment, were used for analyses. Projected internal rates of return (IRR) ranged from 7.3 to 8.5% when 60 to 65% of the landscape was sprayed in a variable-rate pattern (VRP) at 0, 0.6, and 1.1 kg/ha; sprayed in strips with the higher dosage alternating with untreated strips; or completely sprayed with 1.1 kg/ha. Investment capital requirements were reduced when the VRP or strips were used by 49% and 35%, respectively, compared to complete treatment of the landscape with herbicide sprays. Treatment of 80% of landscapes at 2 locations with tebuthiuron in VRPs generated IRRs roughly equivalent to those from 2.2 kg ai/ha of tebuthiuron pellets applied in strips. Complete treatment of management units with 2.2 kg/ha of the pellets generated more additional beef and higher IRRs than did treatment with either pattern, but required from 50% to 75% greater investments of capital. Economic response also differed among sites of differing forage production capabilities and between otherwise similar sites because of variation in botanical composition of the brush stands. For example, IRRs at the locations, respectively, were 6.3 and 1.3% when 2.2 kg/ha of tebuthiuron were applied to sites with deep soils (drainages), 3.1 and <0% following treatment of uplands, and were negative following application to shallow ridges. Sites with a greater proportion of the woody cover contributed by tebuthiuron-susceptible species such as whitebrush yielded greater IRRs from the investment than did sites with heavy cover of honey mesquite (tebuthiuron tolerant). 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 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.