| Researcher(s) |
John Small (CWFS) |
|---|---|
| Year(s) | 2014 |
| Contributor | Central West Farming Systems |
| Trial location(s) |
Nyngan, NSW
|
CWFS are conducting trials at its regional sites that - investigate the impact of different stubble treatments imposed towards the end of the fallow have on nitrogen response (applied as urea) in wheat yield and quality - evaluate the widely used advisor/farmer benchmark of 20 kg actual N required per tonne of expected yield.
• During 2014 stubble treatments imposed late in fallow generally had no impact on N response. • During 2014 generally farmers in the absence of frost or unusual rainfall events during the season were able to reliably predict final yield before sowing. Where a site was N responsive, an N fertilizer rate of 20kg actual nitrogen/ha/per tonne of expected yield produced the most profitable result. • During 2014 split N applications only improved yield and protein at Nyngan which experienced a well above average growing season rainfall. • During 2014 split N applications would have possibly reduced risk at two sites, Lake Cargelligo and Ungarie where a decision not to apply the final 1/3 topdressing may have been made due to soil moisture and rainfall outlook. • The benchmark of 20kg/ha of actual N per tonne of expected grain yield assumes unrealistic N recover rates from soil and fertilizer but never the less it continues to be a widely used “number” during the commercial decision making process to topdress crops.
| Lead research organisation |
Grains Research and Development Corporation |
|---|---|
| Host research organisation | N/A |
| Trial funding source | GRDC CWF00018 |
| Related program |
Maintaining profitable farming systems with retained stubble |
| Acknowledgments |
CWFS would like to acknowledge the support provided by the co-operating farmers, without their in-kind support the trials would not have been possible. The help from Matt McRae, Walkers Ag N Vet, Forbes at the Gunning Gap site, Greg Brooke, NSW DPI at The Nyngan site and Scott Boyd, GOA, Dubbo at the Tullamore site is also acknowledged. The authors also thanks Neil Fettell for his support in compiling this report. |
| Other trial partners | Not specified |
| Crop type | Cereal (Grain): Wheat |
|---|---|
| Treatment type(s) |
|
| Trial type | Experimental |
| Trial design | Replicated |
| Sow rate or Target density | 35kg/ha |
|---|---|
| Sow date | 7 May 2014 |
| Harvest date | 3 November 2014 |
| Plot size | Not specified |
| Plot replication | 3 |
| Paddock history | 20 years no till continous cropping paddock, with rotation dependant on soil moisture at sowing and market outlook. Legumes have not ben a part of the crop mix. Cattle are sometimes grazed over summer if feed is required but stocking rate is too low to be |
| Fertiliser |
63kg/ha MAP fertilizer into moist seedbed with good subsoil moisture. |
| Soil amelioration |
9/4/2014: Stubble treatments imposed |
| Other trial notes |
Cultivation treatment imposed with offset discs.Uneven stubble conditions across the paddock existed on 9 April. Generally it ranged from 1.6 to from 200 to 300mm high with an average load of 3.5t/ha, ranging from 1.6 to 6.0t/ha, ground cover varied from 0 to 100%. It is reasonable to suggest that this variation was due to the way water had drained and settled on the surface duing the fallow.The amount of standing stubble averaged 14% of the total load but varied from 4 to 22%. Availabl |
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.
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