Thirty years of Agricultural Environmental Monitoring: Insights into Water Quality and Erosion in Norway

Excessive nutrient and sediment loads are threatening water quality of inland and coastal waters since decades in Norway. The Norwegian Agricultural Environmental Monitoring Programme (JOVA), established in 1992, aims to measure nutrient and sediment losses from agricultural production systems and evaluate the effectiveness of environmental policies. With only 3% of Norway’s land area suitable for agricultural production, preserving agricultural land from degradation, especially erosion, is crucial. Norwegian agricultural land has been shown to experience high suspended sediment losses (on average 100- 2970 kg/ha/yr), underscoring the need for agricultural catchments monitoring to unravel temporal trends in soil losses, disentangle effects of environmental and management factors, and identify best management practices to maintain good water quality and prevent further soil degradation. The monitoring programme is funded by the Norwegian Ministry of Agriculture and Food and conveys a solid base of knowledge for water management and policy makers. Monitoring data are also widely used for research purposes and to develop, calibrate and validate national nutrient export and erosion models.  

Catchments (currently eleven) were selected to represent key agricultural regions in terms of climate and production systems. JOVA includes catchments dominated by cereal production in eastern and mid-Norway, vegetable production in southern Norway, intensive and extensive dairy farming including grass production in western and northern Norway. Water monitoring stations were constructed at the outlet of each catchment. At these stations, runoff rate is measured, and flow-proportional composite samples are taken and analysed fortnightly (suspended solids, ashes, total P, PO4-P, total N, NO3-N, pH, electrical conductivity). The above-mentioned data is publicly available at https://jovadata.nibio.no/ free of charge. Agricultural management data, including details on dates of tillage, sowing, fertilization, harvest, and pesticide applications, are available upon written request. Water samples from catchments (currently five) are also analysed for a broad spectrum of pesticides. 

Over 30 years of water quality monitoring provided important insights and temporal trends into hydrological regimes, changing agricultural management practices and nutrient and sediment losses from typical agricultural areas in Norway. An increased frequency of large runoff events (>95th percentile) has been observed in some of the catchments, which corresponded with high losses of soil particles and tend to decrease with the prevalence of plant coverage or stubbles. Monitoring data also revealed a response in the frequency of management practices following shifts in subsidy schemes for environmental measures (e.g. incentives for less autumn ploughing in cereal production).  

Long-term water quality monitoring remains essential due to disproportionally large effects of climate change on ecosystems in the Nordic region. Future applications of JOVA monitoring could address the impacts of land use, socio-economic factors and innovative management practices on sediment and nutrient losses, and could further support modelling efforts.  Furthermore, the technical setup of the monitoring enables the comparison between traditional methods and emerging technology, such as sensors. Transnational scientific collaborations among monitoring programmes can pave the way for a more sustainable agriculture at broader regional scales.