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 NO 3- 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 NO 3- leaching from mixed-species hayfields. © Crop Science Society of America.