Phosphorus and nitrogen fertiliser use efficiency of wheat seedlings grown in soils from contrasting tillage systems
2015
Raindog, | Dunsford, K. | McLaughlin, M. J. | McBeath, T. | Mason, S. | Dunbabin, V. M.
AIMS: This paper assessed the effect that the vertical stratification of nutrients in conservation cropping systems of Australia has on phosphorus (P) and nitrogen (N) fertiliser use efficiency. METHODS: Intact soil cores from two long-term tillage experiments, located on a Vertosol and on a Calcarosol were used to assess if tillage system (zero tillage - ZT vs conventional tillage - CT) and soil water influence fertiliser use efficiency (using ³³P and ¹⁵ N) of wheat under controlled growth conditions. RESULTS: Adding P increased shoot growth and P uptake on the Calcarosol, provided the surface remained moist and N was applied. The percentage of plant P derived from fertiliser (Pdff) was greater on the Calcarosol regardless of tillage practice. Pdff increased when the soil remained wet or when N was added. The percentage of N derived from fertiliser (%Ndff) was not affected by tillage practice on the Vertosol but when the soil surface was allowed to dry, it was significantly greater under ZT than CT on the Calcarosol. Adding P increased N fertiliser recovery but tillage practice had no effect. CONCLUSION: The effect of tillage practice on P and N fertiliser use efficiency depends on soil and topsoil water status.
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