The SEPWA Harvest Calculator.
The SEWPA Harvest Calculator has been developed by the South East Premium Wheat Growers Association (SEPWA) to assist grain growers to explore the associated costs and benefits of harvesting at higher grain moisture levels. The Calculator is primarily aimed at wheat and barley grain growers in the south coast region of Western Australia and the potential for them to commence harvest earlier and work for longer hours each day. Growers in other regions of Australia may also find it of interest in their harvest management planning.
The Basic workings of the SEPWA Calculator
For each day a cereal crop stands in the field post maturity, its yield declines. The Harvest Calculator takes this into account when comparing two alternative management approaches to a growers individual harvest program. Research in Esperance WA has shown daily weight losses for cereal crops can be between 0.18 to 0.75% of yield. The Calculator is set at a default average daily weight loss figure of 0.5%, however this may be altered for growers in other regions.
The calculator takes into consideration that earlier more rapid harvest via additional daily harvest hours (in the mornings and evenings when grain moisture is higher) limits the total daily weight loss, by completing the harvest program at a faster rate. However the additional grain harvested each day at the higher moisture content has an associated management cost, be it via blending, aerated storage or drying.
When asked to calculate, the output figures compare
the net financial gain (or loss) of harvesting only under the traditional
12.5% moisture level, to that of the traditional 12.5% moisture level plus
the additional hours of grain harvested at higher moisture. The associated
costs of adopting the chosen high moisture management are built-in into
this net financial comparison.
What about quality downgrades?
Grain quality from weather damage has long been an issue for grain growers. The best possible means for growers to avoid quality downgrading is by harvesting at the earliest possible date. In the calculators’ output, there is a scenario analysis for a weather event on the 12th day of the harvest program. The calculator provides a sensitivity analysis of this potential weather event between $5 and $30 per tonne grain value loss. The net dollar gain/loss from the high moisture management approach is then compared for the whole harvest program in relation to this quality downgrading value.