File(s) under permanent embargo
Nitrogen fertilization value of compost and dried dung in soils with contrasting synthetic nitrogen fertilization histories
journal contribution
posted on 2023-05-21, 17:28 authored by Adam LangworthyAdam Langworthy, Stephen CorkreyStephen Corkrey, Richard RawnsleyRichard Rawnsley, Peter RaedtsPeter Raedts, James HillsJames HillsIf the production of forage for dairy cattle is to become less reliant on synthetic nitrogen (N) fertilizers, there is need to better understand and account for the N contributed by on-farm and imported organic amendments. A 254-day aerobic soil incubation study (typical length of a growing season in many temperate dairying regions) quantified the inorganic (mineral) N supply from a commercial compost and dried bovine dung (i.e., on-farm effluent solids). Amendments were incubated in soils with contrasting synthetic N fertilization histories (i.e., 70–100 vs. 350–400 kg N/ha per year) to evaluate if higher synthetic N fertilization histories would reduce the lag time that often exists between organic amendment application and significant release of inorganic N for plant uptake. This proposition was based on previous research, which showed greater soil inorganic N availability accelerating organic amendment decomposition. Our experiment did find that the release of inorganic N from evaluated organic amendments was greater in soils with higher synthetic N fertilization histories, but that this effect was not apparent until after the first 6-months of this 9-month experiment. Despite this finding, soils with contrasting synthetic N fertilization histories were not found to differ in their initial inorganic N content, nor microbial activity or other physiochemical properties known to affect N mineralization. Our study highlighted the long-term vision needed when transitioning from synthetic N fertilizers to organic amendments, with most of the N present in the compost and dried dung remaining unavailable for forage production (i.e., remained bound in organic carbon-based molecules).
Funding
Dairy Australia Limited
History
Publication title
Grass and Forage ScienceVolume
78Pagination
184–193ISSN
1365-2494Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Wiley-Blackwell Publishing Ltd.Place of publication
United KingdomRepository Status
- Restricted