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Dalgaard T.,University of Aarhus | Bienkowski J.F.,Institute for Agricultural and Forest Environment | Bleeker A.,Energy Research Center of the Netherlands | Dragosits U.,UK Center for Ecology and Hydrology | And 12 more authors.
Biogeosciences | Year: 2012

Improved management of nitrogen (N) in agriculture is necessary to achieve a sustainable balance between the production of food and other biomass, and the unwanted effects of N on water pollution, greenhouse gas emissions, biodiversity deterioration and human health. To analyse farm N-losses and the complex interactions within farming systems, efficient methods for identifying emissions hotspots and evaluating mitigation measures are therefore needed. The present paper aims to fill this gap at the farm and landscape scales. Six agricultural landscapes in Poland (PL), the Netherlands (NL), France (FR), Italy (IT), Scotland (UK) and Denmark (DK) were studied, and a common method was developed for undertaking farm inventories and the derivation of farm N balances, N surpluses and for evaluating uncertainty for the 222 farms and 11 440 ha of farmland included in the study.

In all landscapes, a large variation in the farm N surplus was found, and thereby a large potential for reductions. The highest average N surpluses were found in the most livestock-intensive landscapes of IT, FR, and NL; on average 202 ± 28, 179 ± 63 and 178 ± 20 kg N ha-1 yr-1, respectively. All landscapes showed hotspots, especially from livestock farms, including a special UK case with large-scale landless poultry farming. Overall, the average N surplus from the land-based UK farms dominated by extensive sheep and cattle grazing was only 31 ± 10 kg N ha-1 yr-1, but was similar to the N surplus of PL and DK (122 ± 20 and 146 ± 55 kg N ha-1 yr-1, respectively) when landless poultry farming was included.

We found farm N balances to be a useful indicator for N losses and the potential for improving N management. Significant correlations to N surplus were found, both with ammonia air concentrations and nitrate concentrations in soils and groundwater, measured during the period of N management data collection in the landscapes from 2007-2009. This indicates that farm N surpluses may be used as an independent dataset for validation of measured and modelled N emissions in agricultural landscapes. No significant correlation was found with N measured in surface waters, probably because of spatial and temporal variations in groundwater buffering and biogeochemical reactions affecting N flows from farm to surface waters.

A case study of the development in N surplus from the landscape in DK from 1998-2008 showed a 22% reduction related to measures targeted at N emissions from livestock farms. Based on the large differences in N surplus between average N management farms and the most modern and N-efficient farms, it was concluded that additional N-surplus reductions of 25-50%, as compared to the present level, were realistic in all landscapes. The implemented N-surplus method was thus effective for comparing and synthesizing results on farm N emissions and the potentials of mitigation options. It is recommended for use in combination with other methods for the assessment of landscape N emissions and farm N efficiency, including more detailed N source and N sink hotspot mapping, measurements and modelling. © 2013 Author(s).

Nair N.,University of Western Sydney | Altieri R.,Institute for Agriculture and Forest Systems in the Mediterranean | Esposito A.,Institute for Agriculture and Forest Systems in the Mediterranean | Saville K.,Southern Cross University of Australia
Acta Horticulturae | Year: 2014

This paper is a brief review of recent studies on the feasibility of using olive mill solid waste (OMW) as a major ingredient in the preparation of humified compost (HC), and the application of the HC to soil on the growth of horticultural crops such as Olea europaea (olive), Lycopersicon esculentum (tomato), Lactuca sativa (lettuce), Fragaria vesca (strawberry) and Agaricus bisporus (white button mushroom). OMW-based compost subjected to thermal composting process resulted in significant decrease in the level of polyphenols making it non-phytotoxic. Addition of the compost to olive orchard soil significantly increased total organic carbon and humic substances by 40 and 58% respectively. Similar results on elevated nutritional status and enhanced crop productivity were obtained in trials with other horticultural crops and the cultivated mushrooms. The outcomes of these studies have been the integration of soil health and environmental management practices to achieve sustainable crop production.

Altieri R.,Institute for Agriculture and Forest Systems in the Mediterranean | Esposito A.,Institute for Agriculture and Forest Systems in the Mediterranean | Nair T.,University of Western Sydney
International Biodeterioration and Biodegradation | Year: 2011

This paper presents results obtained on the evaluation of static composting process aimed at bioremediation of the hazardous solid olive mill waste (OMW). The static composting process carried out in gas-permeable polyethylene bags followed the fluctuating temperature and oxygen profiles similar to those seen in aerated composting systems. Static composting resulted in apparent increases and decreases in values for total nitrogen and C:N ratios respectively during the process. The amount of nitrogen (>3%) in the composting end product was in agreement with the Italian legislation (Decreto Legislativo 29 aprile 2010, n. 75) specification for nitrogen fertilizer. A gradual decrease in polyphenols during the storage of compost resulted in a non-phytotoxic composted organic matter high in humic substances. Different respirometric tests also stated high biological stability of the end compost product. © 2011 Elsevier Ltd.

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