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Key findings

Key findings from of the ACP to date:

  1. The underlying soil type and geology can override the effect of nutrient source pressures. There was no clear link between stream nitrogen (N) and phosphorus (P) concentrations and nutrient loading at small catchments scale. Targeted and efficient mitigation measures are required.
  2. Airborne Lidar surveying and new analytical methods of water quality data produced information on pathways and delivery sites that can facilitate targeted and efficient mitigation measures and up-scaled to larger areas. There is a need to identify Critical Source Areas (CSAs) and critical times to tailor advice.
  3. Long-term weather shifts and short-term weather extremes influence N and P loss to water differently. Weather needs consideration and may require different mitigation strategies and real time advice.
  4. There are time lags between agricultural pressures and water quality state. The response time mostly increase with catchment size. Time lags of ca 5 – 10 years need consideration when linking agricultural pressure to water quality state.
  5. Temporal changes in groundwater nitrate concentrations were related to both agronomic, meteorological and hydrogeological factors in two groundwater fed catchments. N application need to be reduced and/or tailored at time of restricted crop growth.
  6. Following heavy rainfall stream P concentrations were gradually reduced during the “closed period” and did not increase in the four week period after the end of “closed period”. Advice on soil moisture conditions can facilitate better decisions on time and location for slurry spreading.
  7. In three catchments the environmental quality standards were frequently exceeded caused by different risks and a new P loss screening tool identified the type of risk.
  8. Sediment was the most common stressor on stream water ecology. Improved management of sediment inputs and influence of point sources in low flow is required.
  9. Most of the sediment losses came from stream bank/bed erosion and road losses on the more common land uses. Soil permeability largely influenced the sediment loss. Sediment loss can be managed by ditch management and by interventions to slow down water.
  10. Safe use of pesticides and pharmaceuticals and/or alternative treatments is required. Herbicides were detected in private drinking water wells and were present in the rivers all year: concentrations peaked in summer and mass loads in winter. Anticoccidial veterinary drugs and anthelmintic residues were detected in groundwater. More research on losses, pathways and impacts are required.
  11. Increasing N and P use efficiency is important from both the agronomic and environmental perspective. The distribution of P sources can be improved. At the field scale, there was often a mismatch between P inputs and the crop/soil P requirements. Advisory support for effective Nutrient Management Planning is required.
  12. A growing acceptance of environmental benefits from regulation was found. The likelihood of adopting certain nutrient management practice is related to demographic and farm structural factors. Farmer cohorts should be considered for land use planning when tailoring policy measures and incentives.
  13. Economic, attitudinal and farm structural factors influence the willingness to adopt a mitigation measure such as a buffer zone. A total of 53% of the catchment farmers surveyed indicated a negative preference of a fenced 10 metre riparian buffer zone under a 5 year scheme. Incentives are needed for adoption of buffer zones.
  14. Knowledge exchange is required for effective Nutrient Management Planning. Farmers prefer a flexible Nutrient Management Plan (NMP) approach combining a durable map with a table. Factors such as fertiliser prices, stocking rates, land use potential, use of milk recording technology, contact with extension services and rainfall patterns influence the P balance and use efficiency. Advisory support relating to NMP is required.