A hindcast and forecast of management of agricultural nutrient losses in Denmark: a change in paradigm (Invited)
Abstract
Four major Action Plans on the Aquatic Environment have been implemented in Denmark since 1987 with the aim to reduce by 50% the nitrogen (N) loading and by 80% the phosphorus (P) loading to the aquatic environment. At the same time the Danish National Aquatic Monitoring and Assessment Programme (NOVA) was launched with the aim to follow the effects of the obligatory implemented management strategies in Danish agriculture. Monitoring of the effects took place in 5 small agricultural catchments in soil water, groundwater and surface waters with annual interviews of farmers practices at field level as well as a general monitoring of nutrient concentrations in groundwater, streams, rivers, lakes and estuaries all over Denmark. Considerable changes in agricultural practice (storage of slurry, ban on slurry spreading in autumn and winter, strict requirements to N-use in animal manure, N-norms to all crops to be fixed to 10% below economic optimum, etc.) have resulted in a reduction of the net N-surplus from 136 to 75 kg N ha-1 yr-1 (45%) and the net P-surplus from 19 to around 0 kg P ha-1 yr-1 (100%) during the period 1985-2011..Twenty-five years of experience gathered from NOVA have shown that the losses of total N (TN) and total P (TP) to the marine environment from both point sources and diffuse sources has decreased with 50% and 50%, respectively. The reduction in TN losses alone amounts to 40%, whereas no general reduction in TP from diffuse losses can be detected. Despite the great efforts in improving the management of N and P in Danish agriculture the sector is today still the major source of both N (80%) and P (50%) in Danish streams, lakes and coastal waters. The ecological conditions in Danish streams, lakes and estuaries are still below the at least good ecological quality required by the EU Water Framework Directive adopted in year 2000. As global demand for food is increasing the Danish Government last year initiated a commission to publish a white book on ';Nature and Agriculture'. The commission has just published their recommendations for the future regulation and management of the Danish agricultural production as the aquatic environment still needs to be improved, and concurrently, the airborne nutrient load on nature must be reduced, and agriculture must help reduce the overall climate change impact. The Commission suggests that the current environmental regulation of agriculture with general fertilizer norms and limits on production cannot alone deal with the challenges, because the costs will be too high for the farmers. They, conclude that it is necessary to explore new territory and make regulation more targeted. Trends in the use of chemical fertilizers in Danish agriculture 1950-2012 and the responses following adopted Action Plans (APAE= Action Plan Aquatic Environment).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.H33M..02K
- Keywords:
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- 0402 BIOGEOSCIENCES Agricultural systems;
- 0470 BIOGEOSCIENCES Nutrients and nutrient cycling;
- 0496 BIOGEOSCIENCES Water quality