Towards closing the nitrogen flow in UK agriculture: An explorative study of integrated food and bioenergy production with increased nitrogen recirculation
Year: 2011
Type: dissertation
Abstract: Nitrogen is an essential growth factor in nature and for food production. It\nexists in many forms, including reactive nitrogen compounds available for plant\nuptake, that can cause environmental impacts in high concentrations. Large\namounts of reactive nitrogen in fertilisers are applied to crop areas, and the\nanthropogenic use of reactive nitrogen has increased manifold during the last\ncentury. Nitrogen in harvest residues and animal manure is recycled to crop fields ineffieciently, and the overall flow of nitrogen through agriculture is practically\nlinear, with substantial losses to air and water. Policies regulate some\nnitrogen practices, but seem not to provide a strong incentive for recycling. A\nmore closed \now of reactive nitrogen within agriculture and the rest of society\ncould reduce the need for nitrogen fertilisers, and also reduce environmental impacts\ncaused by nitrogen leaching, notably eutrophication of aquatic ecosystems.\nPressure is also put on agriculture to meet the increased demand for bioenergy.\nIncreased production of cellulosic bioenergy crops can, in this context, have\na positive effect on the environmental performance of agriculture, and can in\nseveral ways be part of strategies for obtaining a more closed flow of nitrogen\nin the socio-agricultural system.\nThis thesis develops and models an alternative agricultural system, with increased\nnitrogen recirculation. Cultivation of cellulosic bioenergy crops are integrated\ninto the food production to provide nitrogen leaching interception.\nThese biomass production systems are combined with nitrogen recycling. Livestock\nare fed more efficiently than in the current system. Manure is collected and\ntreated through anaerobic digestion for production of biogas and stabilisation of\nvolatile nitrogen. Analyses using a model representation of the alternative agricultural\nsystem show that these measures substantially improve the recycling\nof nitrogen in the system, reduce the losses and decrease the need for chemical\nfertiliser input. The thesis concludes that implementation of certain bioenergy\noptions that enhance nitrogen recycling can give an important contribution to\nclosing the nitrogen flow in agriculture. A second conclusion is that a systems\nperspective on nitrogen is essential for implementation of policies promoting an\nincreased nitrogen recycling within the socio-agricultural system.\n
Author: Sara Alongi Skenhall
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W37782690