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    Peter Newman.

AgLife: Calculating the cost of weeds

A national group dedicated to helping farmers with chemical weed control has developed a tool growers and advisors can use to compare costs of weed-seed controls on their farms.

WeedSmart western extension agronomist Peter Newman has developed the interactive spreadsheet tool using on-farm data and costings.

He has developed the concept based on the many options available that work in reducing weed-seed banks and the wide variations in initial outlay, associated activities and nutrient removal concentration.

“We have good data to suggest that harvest weed-seed control costs are $7 to $19 per hectare and there are only minor differences in the cost between the available tools when compared with using the same farm data,” Mr Newman said.

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“But because every farm is different and small differences in costs per hectare can make a big difference at the whole farm scale, it is important for growers to have confidence they can afford and justify the expenses incurred.”

Some harvest weed-seed control tactics involve the purchase of substantial machinery – such as an impact mill, chaff cart or chaff deck. 

But operational and labour costs might be lower than methods such as narrow windrow burning, which involves low set-up costs but higher nutrient losses and labour costs associated with burning. Invariably narrow windrow burning is the most expensive option in the long-run due to the high nutrient removal cost.

“As a general rule, the cost of harvest weed-seed control is lower per hectare on larger farms with lower yields,” Mr Newman said.

“This is because the capital cost is spread over a larger area, less nutrients are removed because the yields are lower and the low biomass crops allow low harvest heights without slowing down the harvester or using extra fuel. 

“The converse is generally true for smaller farms with higher yields.

“By imputing your own figures into the harvest weed-seed control costing tool you can quickly evaluate the financial impact of the available options.” 

Mr Newman said another important factor to consider was that some technology was relatively new to market and there were unknowns such as the expected life of parts when operating in commercial field conditions. He said as time goes by manufacturers would be able to provide more concrete advice on service and repair costs, and overcome any parts failures. 

He said the spreadsheet was easy to use and took into account capital cost, nutrient spread-loss, cost of ownership, harvest cost, reduction in harvest capacity, fuel use and replacement of wearing parts. 

Users also input data about their farm size and crop yields. 

He said people keen to find out more about harvest weed-seed control and to download the costing tool could visit website

The entire April 29, 2020 edition of The Weekly Advertiser is available online. READ IT HERE!

The entire April 29, 2020 edition of AgLife is available online. READ IT HERE!