Nitrogen and phosphorus losses in surface runoff and drainage water after application of slurry and mineral fertilizer to perennial grass ley

Authors

• E. TURTOLA
• E. KEMPPAINEN

DOI: https://doi.org/10.23986/afsci.5614

Abstract

Losses of nitrogen (N) and phosphorus (P) from perennial grass ley on a fine sand soil were studied with five treatments: no fertilizer (1), cow slurry applied in autumn (2), winter (3) or spring (4), and mineral fertilizer applied in spring (5). For N, the total amounts applied (1992-96) were 0, 772, 807, 805 and 510 kg ha-1 and for P 0, 141, 119, 143 and 107 kg ha-1, respectively. In the first year (establishment of the ley, 1992-93), N losses (drainage + surface runoff) were slightly higher after application of slurry in autumn (with immediate ploughing, treatment 2) than in treatments 1, 4 and 5 (21 kg ha-1 vs. 17 kg ha-1), but the respective P losses (0.7-0.9 kg ha-1) were not affected. During the ley years (1993-96) the N and P losses were increased by surface application of fertilizers and by abundance of surface runoff (83-100% of the total runoff). Nutrient losses were extremely high after slurry application in autumn and winter, accounting for 11% and 33% of the applied N and 17% and 59% of the applied P, respectively. The N losses during the ley years from treatments 1-5 were 13, 62, 191, 23 and 24 kg ha-1, where the proportion of NH4-N was 21, 49, 56, 33 and 39%. The respective P losses were 0.73, 16, 54, 4.2 and 4.0 kg ha-1, where the proportion of PO4-P was 52, 85, 77, 68 and 64%.;