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A field experiment was conducted to find out whether there is any difference in risk of N leaching to groundwater when cattle slurry and ⁄ or mineral fertilizer-N was applied to cut grassland. The experiment was carried out over two consecutive years on two sites (one with a relatively wet sandy soil and one with a relatively dry sandy soil). Treatments were mineral fertilizer-N at annual rates of 0-510 kg N ha )1 year )1 and combinations of sod-injected cattle slurry (85, 170, 250 and 335 kg N ha )1 year )1 ) and mineral fertilizer-N (289, 238, 190 and 139 kg N ha )1 year )1 ). Yield responses indicated that in the short run, 0AE44-0AE88 (average 0AE60) of the slurry-N was as available as mineral fertilizer-N. The total N input from mineral fertilizer and slurry was a worse predictor of nitrate leaching (R 2 adj 0AE11) than the N surplus (i.e. the difference between total N input and harvested N) (R 2 adj 0AE60). The effective N surplus, based on the difference between the summed inputs of the plantavailable N and harvested N, proved to be the best indicator of leaching (R 2 adj 0AE86). Annual N application rates of up to 340 kg plant-available N ha )1 complied with the target nitrate concentration in groundwater of 11AE3 mg N L )1 set by the European Union in both years on the wet sandy soil, whereas on the dry sandy soil none of the treatments did.

Resource use efficiency requires a correct appreciation of the nitrogen (N) fertilizer replacement value (NFRV, percentage of total N applied) of manures. We assessed the NFRVs of the liquid fraction originating from separated pig slurry (MC), untreated pig slurry (PS), untreated cattle slurry (CS), the solid fraction from separated pig slurry (SF) and solid farmyard manure from cattle (FYM) in two consecutive years in silage maize grown on a sandy soil. Maize yields responded positively to each of these N sources applied at rates up to 150 kg of mineral fertilizer equivalents per ha per year (i.e. NFRV 9 total N rate). The observed NFRVs, relative to calcium ammonium nitrate fertilizer, amounted to 78% for MC, 82% for PS, 79% for CS, 56% for SF and 34% for FYM when averaged over both years. NFRVs were positively related to the ammonium-N share in the total N content. Rye cover crop establishment after the harvest of maize reduced nitrate concentrations of the upper groundwater by, on average, 7.5 mg nitrate-N/L in the first year and 10.9 mg/L in the second year, relative to a bare soil. Regardless of the presence of a cover crop, nitrate concentrations responded positively to the applied rate of effective N (total N 9 NFRV) but less to postharvest residual soil mineral N.

Soils form the basis for agricultural production and other ecosystem services, and soil management should aim at improving their quality and resilience. Within the SoilCare project, the concept of soil-improving cropping systems (SICS) was developed as a holistic approach to facilitate the adoption of soil management that is sustainable and profitable. SICS selected with stakeholders were monitored and evaluated for environmental, sociocultural, and economic effects to determine profitability and sustainability. Monitoring results were upscaled to European level using modelling and Europe-wide data, and a mapping tool was developed to assist in selection of appropriate SICS across Europe. Furthermore, biophysical, sociocultural, economic, and policy reasons for (non)adoption were studied. Results at the plot/farm scale showed a small positive impact of SICS on environment and soil, no effect on sustainability, and small negative impacts on economic and sociocultural dimensions. Modelling showed that different SICS had different impacts across Europe—indicating the importance of understanding local dynamics in Europe-wide assessments. Work on adoption of SICS confirmed the role economic considerations play in the uptake of SICS, but also highlighted social factors such as trust. The project’s results underlined the need for policies that support and enable a transition to more sustainable agricultural practices in a coherent way.

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