Measure to manage when double cropping


Grain growers across northern New South Wales and Queensland are now experiencing a vastly improved cropping outlook, thanks to good rainfall in October.

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We have had wildly variable seasons over the past 18 months, starting with an unusually dry summer, then ex-tropical cyclone Debbie, then a persistently dry winter.

It’s no wonder some growers are keen to double crop winter ground with summer crops to take advantage of the recent soil moisture.

Our challenge as fertiliser advisers is to help growers make the most of this opportunity by providing good crop nutrition advice.

It becomes very difficult to apply rules of thumb or averages to crop nutrition when the seasons have been anything but average.

It’s a busy time for everyone, with grain harvesting and summer crop planting occurring simultaneously, but there are quick and easy ways to gain an understanding of the likely nutrient status of paddocks before embarking boots and all into fertiliser application.

Consider running nutrient budgets to determine how much was removed in the 2017 winter crop, using grain testing to calculate the actual nutrients exported.

This winter crop was not an average one, so why rely on the published national average crop nutrient removal figures?

Grain testing is as simple as collecting 400 grams of harvested grain from the header, truck or silo and submitting it to the Nutrient Advantage® laboratory for analysis.

Take samples from each of the winter crop species, or from numerous varieties of the same species to understand which nutrients, and in what quantities, are leaving the farm. Local data is always the best.

By combining this information with yield results you can calculate actual nutrient export data by crop species, paddock or variety. It also provides a very useful base for summer crop fertiliser planning.

Of course, a full crop nutrition program should include regular soil testing.

For growers planning on double cropping, consider soil sampling following winter harvest early in the fallow to see where nutrient levels in individual paddocks are sitting in relation to the critical values for the intended crop.

Soil samples should be taken to the anticipated crop’s rooting depth or to 90 cm, with three to four segments such as 0-10 cm, 10-30 cm, 30-60 cm and 60-90 cm. This will show which nutrients are present and where they are in the soil profile.

It can also reveal whether there are any subsoil constraints, such as salinity or chloride.

Problems with subsoil constraints can vary from time to time due to soil wetting and drying cycles. Subsoil constraints have been prevalent and problematic in winter grain legumes this year due to the dry weather.

Some species are more susceptible to salts than others, so it is worth knowing if the intended crop may be affected. The value of soil testing in these situations is priceless.

If you are struggling to find time to soil test, consider outsourcing to the new mobile sampling service from Nutrient Advantage Laboratory Services.

The new mobile sampling service offers soil sample collection to best management practice standards and can even organise delivery to the laboratory, giving you more productive time with your customers.

The best part is you receive the results from the laboratory to interpret when you are ready, just as if you had taken the samples yourself.

For more information or to discuss double cropping fertiliser strategies, call me on 0417 896 377 or email