Previous syntheses on the effects of environmental conditions on the outcome of plant-plant interactions summarize results from pairwise studies. However, the upscaling to the community-level of such studies is problematic because of the existence of multiple species assemblages and species-specific responses to both the environmental conditions and the presence of neighbors. We conducted the f...

© 2006 Department of Agriculture and Agri-Food, Government of Canada. kg/person/year), providing rural Tibetans with 80% of their total calories and, in many cases, their only signifi cant source of fi ber (15). Traditionally, preparation and consumption of barley in Tibet includes tsampa, a shelf-stable barley fl our product made from ground, roasted barley. Utilization of barley as a food sou...

Baseline information about dryland forest phenology is necessary to accurately anticipate future ecosystem shifts. The overarching goal of our study was to investigate the variability of vegetation phenology across a dryland forest landscape in response to climate alterations. We analyzed the influence of site characteristics and climatic conditions on the phenological patterns of an Arizona, U...

Limited information is available on control of broadleaf weeds in barley and response of barley cultivars to herbicides. Field experiments were conducted from 2007 to 2009 to evaluate post-emergence herbicides for control of broadleaf weeds in four barley cultivars. Herbicide treatments included 2,4-D sodium salt at 500 g ai ha 1, carfentrazone-ethyl at three rates (15, 20 and 25 g ai ha 1), an...

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz(+)) and 2,4-diacetylphloroglucinol (Phl(+)) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization fr...

[1] Predicted precipitation regime changes in arid ecosystems have the potential to alter soil C balance, but the influence of changes in different aspects of precipitation (amount, seasonality, and intensity) and the factors contributing to such effects are poorly understood. We used a process-based ecosystem model (PALS) that was modified, parameterized, and evaluated for a Mojave Desert ecos...

Drylands represent the planet's largest terrestrial biome and evidence suggests these landscapes have large potential for creating feedbacks to future climate. Recent studies also indicate that dryland ecosystems are responding markedly to climate change. Biological soil crusts (biocrusts) ‒ soil surface communities of lichens, mosses, and/or cyanobacteria ‒ comprise up to 70% of dryland cover ...

The Global Drylands Observing System proposed in this issue should reduce the huge uncertainty about the extent of desertification and the rate at which it is changing, and provide valuable information to scientists, planners and policy-makers. However, it needs careful design if information outputs are to be scientifically credible and salient to the needs of people living in dry areas. Its de...

Cotton (Gossypium hirsutum L.) plants grown under field water deficits exhibited an 80 to 85% reduction in leaf area index, plant height, and dry matter accumulation compared with irrigated controls. Midday photosynthetic rates of dryland plants decreased 2-fold, and canopy temperatures increased to 40 degrees C at 80 days after planting compared with canopy temperatures of 30 degrees C for irr...

Clearing of trees and native vegetation over the past 160 years has led to increasing rates of dryland salinization in the Goulburn-Broken Catchment area. In its dryland section, within the Goulburn Highlands, South West Goulburn, and the Broken Highlands subcatchments, hydrologic balance exists. But in the Riverine Plains comprising the Goulburn and Broken Plains sub-catchments, where average ...