Fertilization and Mowing Effects on Unimproved Mixed‐Species Hayfields in Quebec, Canada

Abstract

The objective of this experiment was to evaluate the response of two unimproved mixed‐species hayfields in Quebec, Canada, to management regimes of high fertilization and intensive mowing. Dry matter and nutrient yields, tissue nutrient concentrations, and soil nutrient pools were determined in Bromus–Poa and Pleum–Lolium hayfields fertilized with inorganic fertilizer, liquid dairy manure, or no fertilizer and mown at different intensities (every 2 wk or unmown, during a 12‐wk period). Dry matter and nutrient yields, and tissue nutrient concentrations were similar in plots receiving inorganic and dairy manure fertilizers, but the dry matter yield was 0.6 to 2.8 Mg ha−1 higher in fertilized plots than the unfertilized control. Repeated mowing reduced dry matter yield by 1.5 to 2.7 Mg ha−1, however, tissue nutrient concentration and nutrient yield were greater in mown than unmown plots. The apparent N recovery in a mown, fertilized Pleum–Lolium hayfield was greater than 100%, as the nutrient yields (143 kg N ha−1) were greater than the N fertilizer input of 75 kg N ha−1 Soil NO3− and microbial biomass N concentration were significantly (P < 0.05, Tukey test) lower in fertilized plots that were mown every 2 wk than unmown during the study period. Frequent mowing may be a management option that can reduce soil residual N and thus limit NO3− leaching from mixed‐species hayfields.