Investment

The GRDC proposes to invest in a small 24-month pilot program in Southern and Central regions of NSW to compare the fallow efficiency of stubble residues remaining after the use of conventional and stripper header fronts.

What's new and different: In central and southern NSW fallow efficiencies range from 10% with no cover to 30% with high cover (8-10t/ha) where conventional header fronts are utilized. Fallow efficiency for stripper header fronts are unknown, however this new technology for wheat harvesting leaves the full straw length by stripping the grain from the head. It is hypothesized that the significantly longer straw length reduces wind speed across the soil surface and reduces soil water evaporation. This could widen the sowing window particularly for early sowing opportunities. The potential improvement in fallow efficiency would see water converted at 15 to 20 kg grain/mm transpired for wheat. The winter crop in this region covers some 3.5 m ha of which an estimated 2.1 m ha is under wheat production. A 5% improvement in fallow efficiency would equate to 200 kg/ha. This benefit applied to 10% of the wheat area (0.21 m ha) would provide an additional 42,000 t of wheat production value at $12.6 m (assuming $300/t).

This investment will measure the impact that various forms of stubble architecture have on the capture, maintenance and storage of soil moisture (fallow efficiency dynamics) and provide growers with key crop establishment, development and yield metrics to make decisions regarding the incorporation of stripper fronts in the farming system. Where funds allow the project will also monitor changes in canopy temperature, weeds, disease, insect or rodent impacts on subsequent crops.