Irrigation grain growers can take a number of key lessons into the important 2008 winter crop season after the most difficult winter crop growing seasons on record last year.

Sown on the previous crop moisture, barley yields from three to five tonnes a hectare with no additional irrigation in spring have been reported, raising hopes that similar results can be achieved this year, provided soil moisture is retained.

And with little summer crop about, it makes it even more important to conserve the summer storm moisture so far.

This will involve controlling weeds when small, retaining stubble cover and keeping cultivations to a minimum.

Many growers in the district have been monitoring soil moisture levels in fallows using gypsum blocks so they know "what is in the bank" at the start of the winter cropping season.

A good fallow would result in 50 millimetres of soil moisture.

A look at weather records in the past 30 years gives an indication of the range of yields that can be achieved using fallow and growing season rainfall (April to October) without additional irrigation water (see graph).

When growing season rainfall (GSR) ranges from 150mm to 250mm, yields with good agronomic management can range from 1.4 to 2.1 tonnes a hectare.

This has happened in about 40 per cent of years.

Yields in the range of 2.7 to 4.3 t/ha are possible in 40pc of years when GSR is 250mm to 400 mm - the wetter than average years.

The last two seasons have had GSR of 100mm to 150 mm, which results in expected yields of 0.8t/ha.

These figures show the variability that exists in rain.

The distribution of the growing season rainfall also has a big bearing on the end result.

Note that these figures are based on water conversion figures of 15 kilograms of grain for every millimetre of rainfall, which is achievable with good agronomic practice eg. sowing on time, good soil fertility and crop rotation.

Barley performance in 2007 indicates there is likely to be a shift to more barley in the short term.

Barley has a number of advantages - there are no stripe rust issues, it has less chance of being frosted, has a shorter growing season, and requires less water to finish.

When grown as a dryland crop, it should be sown at dryland rates and a wider range of varieties considered.

An expected increase in cereal diseases, resulting from little balance in crop rotations due to the low allocations, means growers should choose barley paddocks that are lower risk of having disease or weed problems.

Break crops such as canola, faba beans, field peas and chickpeas are also good options with price prospects looking good.

More balance in the 2008 winter crop mix would be a wise management decision for the future.

Contact Kieran O’Keeffe, Griffith, (02) 6960 1319.