Farming system can cope

Farming systems research agronomists, Guy McMullen and Giles Butler
Farming systems research agronomists, Guy McMullen and Giles Butler, with a soil moisture probe in a no-till stubble paddock, where soil surface temperature is likely to be 20 degrees less than bare soil during summer.

Tools developed for a variable climate more than 30 years ago are likely to have an even greater role in tackling climate change.

NSW Department of Primary Industries (DPI) research has already proven the moisture saving benefits of no-till – now the techniques are offering new hope for farmers facing the challenge of climate change.

Leader of the northern farming systems unit, Bob Martin, said no-till and response cropping would allow farmers to spread the risk for summer cropping, with climatologists forecasting a 40 to 50 year period of drier weather.

“Experts are predicting the north-west region will become warmer and drier, with more extreme events, and these effects could impact on summer cropping more than winter cropping,” Dr Martin said.

“At the moment a lot of farmers are planting their sorghum later, some as late as mid November, and it appears that only half the area went in last year.

“That’s partly due to the low rainfall in the early part of summer, but it’s also because farmers who haven’t adopted no-till missed a window of opportunity.

“If they had soil moisture at the beginning of September they could have sown a crop.

“However, if they delayed until mid October or November and haven’t had any rain, they may have lost the soil moisture at the surface and can’t sow deep enough to get sub-soil moisture.

“Longer term a better option would be to grow summer crops with no-till because the benefits are well and truly proven.”

Dr Martin said farmers should try to hedge against the risk of missing a summer planting opportunity by adopting the tools developed for a variable climate.

“If we are going to have drier weather, no till stores soil water but also provides ground cover which reduces surface soil temperatures.

“The soil surface temperature under crop residues is likely to be 20 degrees less than bare soil during summer and this heat has a big drying effect.

“The flexibility of growing alternative crops such as sunflower and maize – two that we can sow a month earlier than sorghum – means we can sow from the end of August and avoid the peak summer temperatures.

“We will use Agricultural Production Simulator or APSIM modelling to see how the various alternatives stack up over the long term.

“On top of [drier weather], they tell us it is going to be hotter, so we want to model some of these scenarios and look at what are the best cropping strategies to cope with these changes.”

Some of the work has already been done, with maize and sunflower planted at Moree and Tamworth in mid September performing well despite the dry conditions.

Sunflowers yielded up to 1.9 tonnes per hectare, while maize yields were up to 3.5 tonnes/ha and the prices of those crops are way above sorghum.

The next phase will involve maize, sunflowers and sorghum varieties planted at the end of August and maybe a month later, plus a later scenario where quick maturing varieties will be planted early January.