Showing results for: Nitrogen
This paper, which looks at the impact of agricultural intensification on soils across Europe, suggests that differences in the intensity of land use significantly affects soil ecosystems and the services they provide. High intensity arable land use is found to a have lower diversity and biomass of soil organisms than lower intensity arable or permanent grassland, and that this affects the carbon and nitrogen cycles in the environment.
This interesting paper calculates the a. nitrogen footprint and b. nitrogen investment factor associated with the average production of 12 agricultural commodities in the EU – 6 plant and 6 livestock products (excluding fish and aquatic products). The nitrogen footprint is defined as the total N losses to the atmosphere resulting from the production of a defined unit of food, while the N investment factor calculates the amount of N input needed to produce a specified amount of N in the food. Since N is the building block of protein, the latter is a useful way of looking at the issue, particularly when it comes to considering the relative merits of plant (eg. pulses and legumes) versus animal sources of protein.
This IFPRI (International Food Policy Research Institute) policy note summarises the results of a study that compares the effects that different technologies have on crop yields and resource use, in particular arable land, water and nutrient inputs. It models technology-induced changes in crop yields and considers how the mix of technology uptake can influence the global food market through changes in food prices and trade flows, as well as calorie availability, in particular for developing countries.
A new study by researchers at University of Calgary published in the Proceedings of the National Academy of Sciences, suggests that the long-term legacy of past fertilizer applications must be considered in reducing nitrate contamination of aquatic ecosystems. The study finds that nitrogen fertilizer leaks out in the form of nitrate into groundwater for much longer than was previously thought. The long-term tracer study revealed that three decades after synthetic nitrogen (N) was applied to agricultural soils, 12–15% of the fertilizer-derived N was still residing in the soil organic matter, while 8–12% of the fertilizer N had already leaked toward the groundwater.
New evidence suggests that a chemical mechanism operating in the roots of a tropical grass used for livestock feed holds enormous promise for reducing the emission of nitrous oxide. N2O is the most harmful of the warming gases, with a global warming potential 296 times that of carbon dioxide. According to the UN Food and Agriculture Organisation (FAO), the livestock sector accounts for 65 percent of the nitrous oxide emitted.
A report commissioned by the United Nations Environment Programme (UNEP) has been published , focusing on the environmental problems caused by nitrogen, phosphorous and other nutrient flows and identifying the actions that could be taken to reduce excessive nutrient use. The research was led by Mark Sutton at the UK’s Centre for Ecology and Hydrology and carried out by 50 exports from 14 countries.
The Global Partnership on Nutrient Management (GPNM) and the International Nitrogen Initiative (INI) have published a ‘key messages’ statement for Rio+20. The document highlights the problems caused by excessive nutrient use on the one hand, and insufficient use on the other, and identifies nine key actions as being central to improving nutrient use efficiency, thereby improving food and energy production while reducing N and P losses that pollute our environment.
FCRN mailing list member Anna Flysjö has successfully defended her thesis. The thesis takes the form of a summary overview section and 6 papers (5 of them published journal papers). Details as follows:
The PhD project has focused on some of the most critical methodological aspects influencing GHG emission estimates of milk and dairy products and how the methodology can be improved. In addition, the CF for different types of dairy products has been analysed. Based on these results, mitigation options have been identified along the entire dairy value chain.
This paper considers uncertainties in estimating global N2O emissions from agriculture and in projecting future emissions. As regards mitigation, it highlights the potential achievable through dietary change (away from meat and dairy consumption), and of food waste reductions.
Two studies, one in Nature and the other in Science present evidence to demonstrate the importance of biodiversity in maintaining long term ecosystem productivity and sustainability.
The Soil Association has published 'Just say N2O: From manufactured fertiliser to biologically-fixed nitrogen.' This report reviews the extent to which organic systems can meet the double challenge of reducing nitrogen losses and building stores of soil organic nitrogen so as to reduce dependency on manufactured nitrogen.
This is an interesting presentation, given by Eric Davidson of Woods Hole Research Center, at the recent Planet under Pressure conference in March 2012. The presentation is a summary of a paper he has forthcoming in Environmental Research Letters.
A couple of papers by FCRN mailing-list members on soil carbon sequestration: these conclude that the benefits of soil carbon sequestration activites (through the incorporation of organic matter and/or reduced tillage) have been overstated and may distract attention from other priorities, including halting deforestation and improving N use efficiency.