Big variations in water use

Farmer Ian Sutherland and his daughter Kylie
Coleambally farmer, Ian Sutherland (right), and his daughter, Kylie, downloading soil moisture data from their seed wheat crop.

A survey of 53 Coleambally wheat crops in 2006 revealed big variations in both yields and amount of water used to grow a crop.

Between seven and 26 kilograms of grain were harvested for each millimetre of water applied per hectare.

Where levels of water used were very low, this was partially accounted for by water shortages because of the drought. These growers were either unwilling or unable to water wheat last spring.

Other factors, such as late sowing and lack of suitable rotations, had a big bearing on the end result.

Half the crops sown reached the benchmark of 16kg of grain per millimetre of water applied to one hectare. Variations were also uncovered in yields as a result of the ways of preparing and sowing crops.

About half of the 53 wheat crops were grown on contour layouts, and had an average yield of 3.8 tonnes/ha. Around 18 per cent of crops were grown on bordercheck layouts with an average yield of 5.1 tonnes/hectare.

The biggest yields came from the 30pc of crops grown on beds. These had an average yield of 6.9t/ha.

The data shows the yield advantage of the better layouts and soils. Comparison with the same survey conducted in 2001 indicates growers have started to move to permanent raised bed paddocks on dedicated sections of their farm.

Thirty per cent of the area surveyed used crops grown on beds, compared to 15pc in 2001.

NSW DPI is working with the local irrigation company, Coleambally Irrigation, to increase the uptake of soil moisture assessment equipment and improve the interpretation of soil moisture data in summer and winter crops in the district.

A pilot program with five growers will occur this summer season and lessons learnt will be extended to other irrigation farmers.