Theme 06: Abiotic Constraints to Forage Production from Grasslands
Description
Experiments were conducted within a long-term nitrogen (N) fertiliser experiment under grazing. The objective was to examine N response efficiencies (kg dry matter (DM)/kg N) and herbage crude protein (CP) content to fertiliser N applied under dry soil conditions (gravimetric soil moisture content of 17% at 10cm; soil field capacity = 38% and wilting point = 11%) during autumn (April 1999) and late spring (November 1999) in southeastern Australia. Visually, N treated plots were greener in colour than control (no N) plots. No differences were recorded in primary or residual DM yields, N response efficiencies, and pasture growth rates between N fertilised plots and control plots for both autumn and late spring applications. Fertiliser N, however, had increased herbage CP content six weeks after application in autumn, but had no effect on primary (autumn and late spring applications) or residual CP content in late spring. It was concluded that N fertiliser applications under dry soil conditions are economically and environmently questionable.
Citation
McKenzie, Frank R. and Jacobs, Joseph L., "Nitrogen Response Efficiencies from Grazed Dairy Pastures under Dry Conditions" (2021). IGC Proceedings (1993-2023). 9.
https://uknowledge.uky.edu/igc/19/6/9
Included in
Nitrogen Response Efficiencies from Grazed Dairy Pastures under Dry Conditions
Experiments were conducted within a long-term nitrogen (N) fertiliser experiment under grazing. The objective was to examine N response efficiencies (kg dry matter (DM)/kg N) and herbage crude protein (CP) content to fertiliser N applied under dry soil conditions (gravimetric soil moisture content of 17% at 10cm; soil field capacity = 38% and wilting point = 11%) during autumn (April 1999) and late spring (November 1999) in southeastern Australia. Visually, N treated plots were greener in colour than control (no N) plots. No differences were recorded in primary or residual DM yields, N response efficiencies, and pasture growth rates between N fertilised plots and control plots for both autumn and late spring applications. Fertiliser N, however, had increased herbage CP content six weeks after application in autumn, but had no effect on primary (autumn and late spring applications) or residual CP content in late spring. It was concluded that N fertiliser applications under dry soil conditions are economically and environmently questionable.
