Case study: Ian Manwaring, Condobolin NSW – Fallow management (stubble) in a stubble retained system.
Enterprises: Mainly cropping with wheat, barley and oats, sheep (mainly Dorper), cattle and goats.
Soil type and pH: Red, hard setting with pH ranging from 5 to 6.5.
The Manwarings farm 22,000 ha North West of Condobolin. They run a mixed farming operation and on occasion take in stock on agistment as a sideline.
They classify themselves as conventional croppers, using whatever tools in the shed they need to fit any given season.
Ian generally crops a paddock for three years before putting it back into a pasture phase. The sequence is usually wheat followed by wheat, then barley under sown with lucerne, medics and clovers. Oats is usually grown for grazing and for grain and hay.
The pasture phase usually lasts for three to five years depending on how well the pasture is performing.
Post-harvest management and weed control:
Paddocks are sometimes grazed after harvest depending on the situation at the time. If rain has decreased the feed value they more likely spray or cultivate.
One useful aspect of grazing is allowing the stock a parasite free paddock after drenching which has a flow on effect of maintaining cleaner pastures.
When grazing the Manwarings have no set stocking period, again depending on the condition of the stubble and the season they may graze heavier stubble longer than normal if pasture is poor over the remainder of the property. This also allows some thinning of the stubble for subsequent sowing.
They like to have any operations carried out by the end of January.
Because of their light cropping regime followed by a lengthy pasture phase the Manwarings have not noticed any weed resistance developing at this stage.
Ian sees the biggest value in retained stubble being the retention of moisture. With such marginal country this is considered a valuable component of stubble retention.
However, they remain flexible and use the most economic tools available and if stock returns are outperforming cropping they tend to lean more towards maximising stock returns.
Ian has noticed that the mulch effect of chaff from the harvest is the predominant cause of moisture retention, far outweighing the standing stubble in the paddock. Ian feels that retaining heavy stubbles has led to Nitrogen tie-up in some years so he remains committed to being flexible in his cropping program.