The management of crops following wheat tend to be the least profitable in the cropping rotation. Work was undertaken to investigate options for improving the profitability of these crops (including wheat on wheat).
More generally, previous work has highlighted considerable spatial variation in paddock conditions. Work has been undertaken to confirm that it is better to treat paddocks according to this variation as opposed to applying general paddock rates of inputs and to produce advice on the best technologies and strategies to use when undertaking a more site-specific approach to input allocation.
This project investigated the case for variable rate and also investigated management options for crops grown on wheat stubbles. Considerable ground truthing including soil testing, crop monitoring and soil moisture monitoring was undertaken to confirm real differences between delineated zones.
The key findings of this project were that:
- Wheat following wheat can be a viable alternative particularly to growing crops such as lupins and canola.
- To maximize yields, wheat after wheat requires protection from root diseases and possibly more nitrogen than would be required by wheat after canola.
- Using barley or triticale in the crop rotation is a more economic option than a higher proportion of canola or lupins.
- Barley and triticale require high inputs (similar to wheat) to maximise their yield potential.
- Barley grain quality is not significantly affected by N or fungicide applications until the yield is maximized.
- Wheat responds to 5-10 kg/ha of P at high soil test levels (80 mg/kg Colwell) in dry years.
- Crops with low initial tiller numbers can be manipulated to yield well.
Conditions in paddocks driving underlying fertility and yield potential vary considerably and inputs should be applied according to the needs of individual zones as opposed to general paddock applications. EM surveys, elevation maps and yield maps are all important when zoning paddocks. Once boundaries are drawn, zones should be ground truthed and input rates can then be determined through soil test results and/or previous nutrient removal based on yield maps.
Following the first wheat crop in a rotation, profits will be maximized by:
- Keeping the % of alternate crops such as canola and pulses to the minimum required for a sustainable rotation in terms of disease breaks
- Using barley on some wheat stubbles
- Treating barley and triticale the same as wheat in terms of inputs of fungicide and N
- Controlling root diseases if wheat is growing on wheat stubbles, which would then see wheat on wheat as an additional profitable option.
Results can be found in “Making Money out of Precision Agriculture, results from the Riverine Plains Inc project “ Improving Winter Cropping Systems in the Riverine Plains, 2009”.
Results from the 3rd Crop Program, a report from the Riverine Plains Inc project “Improving Winter Cropping Systems in the Riverine Plains, 2009”
The 3rd crop final report (include link), includes:
- Crop comparison experiment
- Wheat maximum yield experiment
- Barley maximum yield experiment
- Triticale maximum yield experiment
- Wheat fungicide experiment
- Barley fungicide experiment
- Wheat phosphorus and nitrogen experiment
- Wheat inputs experiment
- Wheat trace element experiment
- Sulphur and zinc experiment
The project also produced a draft protocol for high yield and high profit triticale (2007) , as well as a draft protocol for high yield and high profit barley (2007).