A lysimeter experiment was carried out over 3 years to clarify efficient use of anaerobically digested cattle slurry (ADCS) produced from a biogas plant on the basis of the efficiency of its nitrogen (N). Timothy (Phleum pratense L.) was the test crop, with ADCS applied at different rates and times. Nitrogen uptake by the grass varied from 18 to 30% of total N (T-N) in the ADCS, with spring application (late April) increasing efficiency compared to autumn application (late October). Ammonia N (NH 3 -N) volatilization was around 13% of the ADCS T-N, irrespective of application rate and time. Nitrogen leaching, of which the major form was nitrate N (NO 3 -N), ranged from 6 to 12% of ADCS T-N. The lowest leaching loss was associated with the standard rate of spring application, giving a total of 32 g m −2 (320 kg ha −1 ) in 3 years as ammonium N (NH 4 -N) derived from the ADCS. Nitrous oxide N (N 2 O-N) emission loss from the soil amounted to less than 0.1% of ADCS T-N. The standard rate of spring application of the ADCS gave the maximum N use efficiency (for dry matter production) of the ADCS and the minimum N loss. We concluded, under the experimental conditions, that the standard rate ADCS application, in early spring, gave the highest N efficiency in grass dry matter production, and reduced environmental risks.