SignificanceGrowing food in cities for human consumption could be one means of increasing global food supply in the face of rising population growth and global food security concerns. While previous studies have shown that urban agricultural systems are productive, few studies provide yield figures that incorporate data on the inputs used to achieve the outputs. Across 13 urban community gardens, we show that yields were nearly twice the yield of typical Australian commercial vegetable farms. However, economic and emergy (embodied energy) analyses indicated they were relatively inefficient in their use of material and labor resources. Balancing the sustainability of urban food production with the cost of inputs is important to determine the trade-offs required to achieve high yields.

Land degradation, particularly soil erosion, is currently a major challenge for Nepal. With a high rate of population growth, subsistence-based rural economy, and increasingly intense rainfall events in the monsoon season, Nepal is prone to several forms of land degradation, such as floods, landslides, and soil erosion. To understand the causes, impacts, and possible management options for soil erosion, a review on the causal factors, status, and amelioration measures for land degradation in Nepal was conducted based on recent information available in national and international journals and grey literature. Intense rainfall and conventional tillage practices coupled with poor soil structure and steep slopes are the main drivers of soil erosion. Soil erosion leads to losses in soil and crop productivity, pollution of land and water resources, and a loss of farm income. Strategies to manage erosion include mulching, cover cropping, contour farming, strip cropping, and conservation agriculture practices, along with bioengineering techniques. Land degradation issues are a prime policy focus in Nepal, including national three- and five-year plans. However, these policies have been generally ineffective in reducing soil erosion, landslides, and floods in relation to the set targets. Realistic plans need to be formulated in Nepal focusing more on capacity enhancement and local participation to actively influence land-degradation processes.

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Chejara VK, Kriticos DJ, Kristiansen P, Sindel BM, Whalley RDB & Nadolny C (2010). The current and future potential geographical distribution of Hyparrhenia hirta. Weed Research50, 174–184. Summary Hyparrhenia hirta is a pasture grass that has become highly invasive in several parts of the world, including Australia where it has become a serious environmental weed in recent decades. Knowledge of the likely potential distribution and relative abundance of this invasive species, under current and future climate scenarios, will help biosecurity and weed control authorities to plan better strategies to manage the invasion. The CLIMEX modelling package was used to investigate the impacts of climate change on the potential global distribution of H. hirta, based on eco‐physiological data. The worldwide potential distribution of H. hirta under current climatic conditions is vast and far greater than the current distribution, with suitable climate conditions extending over much of the tropics and subtropics. Under future climate scenarios, the range of H. hirta is likely to expand into areas currently too cold for its survival and contract from areas that are projected to become hotter and drier under climate change. The effects of likely climatic scenarios on the global potential distribution of H. hirta are sufficiently great that they should be considered routinely in strategic control plans for biotic invasions. Changes in the potential range of an invasive species such as H. hirta, under global warming scenarios, will mean that it could invade new jurisdictions. Knowledge of this emerging threat could help to formulate effective prevention, surveillance and response measures in these presently marginally unsuitable regions.

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This study is the first to demonstrate an increase in fruit abscission in an evergreen tree in response to pruning. The effect appeared to be related to competition for carbohydrates between post-pruning shoot growth and fruit development and was local, with shoot growth on pruned branches having no effect on fruit abscission on unpruned branches.

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