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Condujimos experimentos en invernadero para comparar las respuestas fotosintéticas y de crecimiento de dos zacates anuales invasores ( "Downy brome" = Bromus tectorum L. y"Medusahead" = Taeniatherum caput-medusae (L.) [Nevski]), 6 zacates cespitosos y 7 zacates rizomatosos a la aplicación del her bicida sulfosulfuron (1 -(2-ethylsulfonylimidazo [1,2 -a]pyridin -3 ylsulfonyl)-3-( 4, 6-dimethoxypyrimidin -2-yl)urea). Nuestros obje tivos fueron identificar patrones generales de respuesta de las especies y probar la hipótesis de que el sulfosulfuron indujo una reducción de la actividad fotosintética y que el crecimiento de los tallos sería mas pronunciado en plantas pequeñas en relación a plantas grandes. Las plantas pequeñas se trataron con sulfosul furon (70 g ai ha') en un experimento realizado en primavera las grandes en uno efectuado en verano. " Wildryes" y " Bromes" fueron consistentemente dañados, mientras que 5 de los "Wheatgrasses "no fueron susceptibles al sulfosulfuron. Los zacates rizomatosos generalmente experimentaron mas daño por el sulfosulfuron que los zacates cespitosos. Estos resultados sug ieren que el sulfosulfuron podría ser una herramienta útil de manejo de pastizales para controlar las especies invasoras no deseadas de zacates anuales sin afectar significativamente el crecimiento y fisiología de los zacates deseables del pastizal. r ange grasses AbstractWe conducted greenhouse experiments to compare photosynthetic and growth responses of 2 invasive annual grasses (downy brome = Bromus tectorum L. and medusahead = Taeniatherum caput-medusae (L.) [Nevski]), 6 caespitose grasses, and 7 rhizomatous grasses to the herbicide sulfosulfuron (1-(2-ethylsul-idin-2-yl)urea). Our objectives were to identify general patterns of species responsiveness and test the hypothesis that sulfosulfuron induced reduction in photosynthetic activity and shoot growth would be more pronounced in small relative to larger plants. Small plants in a spring experiment and large plants in a summer experiment were treated with sulfosulfuron (70 g ai ha'). Wildryes and bromes were consistently injured; whereas, 5 of the 7 wheatgrasses were not susceptible to sulfosulfuron. Rhizomatous grasses generally experienced greater damage fromThese results suggest that sulfosulfuron would provide a useful rangeland management tool to control unwanted invasive annual grasses without significantly hindering growth and physiology of desirable rangeland grasses.

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Farmers in the Zuni area of the semiarid American Southwest have successfully cultivated maize and other crops for over three millennia without using artificial fertilizers. Zuni agricultural fields are among the oldest, more or less continuously cultivated areas in the United States. Traditional Zuni agriculture is based on runoff farming, a system whereby runoff and organic‐rich sediment generated in small watersheds are captured and directed onto fields for crop use. We conducted a study to compare soil properties associated with paired and unpaired cultivated, abandoned, and uncultivated fields to evaluate the long‐term effects of cultivation on soil quality. Sampling and analytical methods of this research are especially applicable to geoarchaeological studies of anthropogenic effects on soil fertility and agricultural sustainability in ancient and traditional historical farming systems. Results of the Zuni soil study indicate that cultivation has altered some soil properties, including bulk density, organic carbon, total nitrogen, and C:N ratios in paired fields, but there is no indication that agricultural soils are degraded. This assessment supports the perception of Zuni farmers that long‐term cultivation has not caused a decline in agricultural productivity. © 2005 Wiley Periodicals, Inc.