Fertilization trajectory of the root crop Raphanus sativus across atmospheric pCO2 estimates of the next 300 years

Plant biomass is known to increase in response to elevated atmospheric CO₂ concentration (pCO₂); however, no experiments have quantified the trajectory of crop fertilization across the full range of pCO₂ levels estimated for the next 300 years. Here we quantify the above- and below-ground biomass response of Raphanus sativus (common radish) across eight pCO₂ levels ranging from 348 to 1791 ppmv. We observed a large net biomass increase of 58% above ground and 279% below ground. A large part of the net increase (38% of the above-ground and 53% of the below-ground) represented biomass fertilization at the high levels of pCO₂ (700–1791 ppmv) predicted if fossil fuel emissions continue unabated. The trajectory of below-ground fertilization in R. sativus greatly exceeded a trajectory based on extrapolation of previous experiments for plants grown at pCO₂ < 800 ppmv. Based on the experimental parameters used to grow these plants, we hypothesize that these experiments represent the maximum CO₂ fertilization that can be achieved for this plant growing under low light levels. If the below-ground biomass enhancement that we have quantified for R. sativus represents a generalized root-crop response that can be extrapolated to agricultural systems, below-ground fertilization under very high pCO₂ levels could dramatically augment crop production in some of the poorest nations of the world, provided that water resources are sufficient and sustainable.     

Cognitive and institutional influences on farmers’ adaptive capacity: insights into barriers and opportunities for transformative change in central Arizona

The prospect of unprecedented environmental change, combined with increasing demand on limited resources, demands adaptive responses at multiple levels. In this article, we analyze different attributes of farm-level capacity in central Arizona, USA, in relation to farmers’ responses to recent dynamism in commodity and land markets, and the institutional and social contexts of farmers’ water and production portfolios. Irrigated agriculture is at the heart of the history and identity of the American Southwest, although the future of agriculture is now threatened by the prospect of “mega-droughts,” urbanization and associated inter-sector and inter-state competition over water in an era of climatic change. We use farm-level survey data, supplemented by in-depth interviews, to explore the cross-level dimensions of capacity in the agriculture–urban nexus of central Arizona. The surveyed farmers demonstrate an interest in learning, capacity for adaptive management and risk-taking attitudes consistent with emerging theory of capacity for land use and livelihood transformation. However, many respondents perceive their self-efficacy in the face of future climatic and hydrological change as uncertain. Our study suggests that the components of transformational capacity will necessarily need to go beyond the objective resources and cognitive capacities of individuals to incorporate “linking” capacities: the political and social attributes necessary for collective strategy formation to shape choice and opportunity in the future.     

Training for benchmarking: The alliedsignal experience

Integration of TQM principles and tools into environmental management decisions is essential to the ultimate success of businesses. Benchmarking is one of the most powerful TQM tools for quickly and effectively improving processes. To realize the maximum benefit from benchmarking, it—like any other TQM tool—must be used appropriately and properly. In this article training techniques are presented that will help companies realize the full potential of their benchmarking efforts.     

Pharmacokinetic model of dioxin and furan levels in adipose tissue from Sawmill work involving chlorophenate fungicides

Sawmill workers in British Columbia (B.C.), Canada, have been exposed to chlorophenate fungicides which are known to be contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Due to concern about the potential of these workers to have significant body burdens of PCDD/Fs, and the absence of measurements in these worker, a single-compartment pharmacokinetic model was developed to estimate the concentration of PCDD/Fs in the fat tissue of the sawmill workers. Data from a large cohort of B.C. sawmill workers and literature-based data on chlorophenate exposures and PCDD/F concentrations in chlorophenates were used in Monte Carlo simulations to predict a PCDD/F body burden distribution. The median concentrations of HxCDF and HpCDF predicted using the model for the B.C. sawmill worker population exceeded the range measured in unexposed populations. PeCDF and OCDF concentrations exceeded the range measured in unexposed populations at the 70th percentile of the model-predicted distribution, and PeCDD at the 90th percentile. The primary limitation of the model was the scarcity of input data about actual dermal and inhalation exposures to chlorophenates.     

New Zealand drivers study: developing a methodology for conducting a follow-up study of newly licensed drivers

PROBLEM: In recent years, there has been a significant reduction in traffic crash injury among young people, but they continue to be overrepresented in the traffic crash statistics. To improve this situation, sound scientific evidence is needed to develop effective policies and programs. METHOD: The aim of the proposed study is to provide this evidence by examining early driving and driving-related experiences of newly licensed drivers as they progress through the learner-, restricted-, and full-license stages of the graduated licensing system and to determine the impact of these experiences on subsequent negative traffic-related outcomes (risky driving behavior, injury traffic crashes, noninjury traffic crashes, infringements, convictions). Given the size and complexity of the proposed study, a comprehensive pilot study was undertaken to determine the feasibility of conducting a New Zealand-wide cohort study of newly licensed drivers. RESULTS: This article describes the pilot study process and the methodology that has been developed for the New Zealand-wide study.     

Snowmobile impact on old field and marsh vegetation in Nova Scotia,Canada: An experimental study

A study was carried out in Nova Scotia, Canada, to experimentally assess the effect of snowmobiles on old field and marsh vegetation. Snowmobile treatments ranging from a single pass to 25 passes (five passes on five separate days) were administered. The first pass by a snowmobile caused the greatest increase in snow compaction-roughly 75% of that observed after five sequential passes. Snowmobile treatment resulted in highly significant increases in snow retention in spring. Frequency was more important than intensity in this regard.Standing crop and species composition were measured the following summer. Standing crop in the field showed a significant reduction with increasing snowmobile use; frequency of treatment (p < 0.01) was more important than intensity (p = 0.125).Stellaria graminea, Aster cordifolius, Ranunculus repens, andEquisetum arvense all showed significant (p < 0.05) differences in percent cover resulting from the treatment. Marginally significant changes were observed inAgrostis tenuis andPhleum pratense Marsh vegetation showed no significant effects of snowmobile treatment. This may have been because of solid ice cover during the winter.The literature is critically reviewed. It is concluded that snowmobile use can have a highly significant effect upon natural vegetation. Management suggestions are made.