by Peter Reading
The Crop Doctor
Grains Research and Development Corporation (GRDC)

Without referring to the “cloud with a silver lining” cliché, might I suggest the current oil and energy crisis could influence northern region graingrowers to include more legumes in their farming systems.

For some years now agronomists have been arguing that, to be sustainable long term, 20 to 30 per cent of the region’s cropping land should be planted to pulses and oilseeds.

Currently it’s only about a fifth of that, but, in a paper promoting the value of grain legumes in farming systems, Kingaroy soils specialist Mike Bell suggests the “free” nitrogen legumes can fix in the soil is the one area where growers can sustainably reduce energy inputs.

A principal scientist with Queensland’s Department of Primary Industries and Fisheries (QDPI&F), Mike heads several soils focused projects supported by the Grains Research and Development Corporation (GRDC).  

He says the main inputs on cropping farms tend to be oil-based – fertiliser and chemicals as well as the more obvious fuel for trucks, tractors and other machines.

The full effects of rising world energy costs and diminishing oil resources for farm fuel and fertiliser are not fully understood or realised, but all predictions are towards a negative outlook.

In that situation, driving farming systems with legume-derived nitrogen will be increasingly critical and efficient, adapted grain-legume rotation crops and agronomics will be the key to keeping Australian farmers globally competitive.

Mike says the value of legume rotations on soil health and subsequent crops has been demonstrated in trials and farming systems research across the region – consistently delivering yield increases of 15 to 25 per cent in following cereals.

But poor soil health continues to have a huge impact in all major cropping systems, primarily because of a lack of well adapted, low-risk rotation crops.

It’s estimated root lesion nematode and crown rot are responsible for lost wheat production of about $60 million a year in Queensland alone.

And current research suggests that additional losses in these crops and sorghum due to minor pathogens and poor general soil biology may be more than $100 million a year.