Wide and skip row configurations have their place in sorghum, but not in dryland maize, according to the results of a Grains Research and Development Corporation (GRDC) supported study of low risk production strategies for the crop.

The finding is contrary to the general belief at the start of the three years research that the wide or skip row systems would stabilise maize yields in marginal dryland environments, as they have for sorghum.

Instead, the project¹s recommendations for dryland maize production in marginal western areas of the northern grains region are to sow the crop: o early August to early September, o with at least two hybrids of different maturities to reduce the risk of high temperatures at tasselling, and o only when soils contain at least 120 millimetres of stored water.

Project leader, CSIRO agronomist Michael Robertson, said the root system in maize was not well adapted to exploit the extra moisture potentially available under wide or skip rows.

In skip row studies, sorghum seemed able to extract considerably more water than maize. In skip rows, maize dried the soil well in the row itself but quite poorly out in the middle of the skip.

There was evidence that, even in wide (1.5 metre) rows, maize was not able to use all the water in the middle of the row space, compared to in the row.

Researchers used long term APSIM computer simulations to compare the reliability of maize sown in early September, and sorghum sown a month later, on 120mm plant available water, on the western downs of Queensland.

Yield variability was greater for maize and, in 10 per cent of years, no crop would be harvested, due to water stress around flowering. Sorghum yield always exceeded 1.5 tonnes to the hectare.

In this environment sorghum never yielded more than 3 tonnes to the hectare, while maize yielded more than 3 tonnes about one year in three. On average APSIM estimated sorghum yield at 2.468 tonnes to the hectare while the maize yield was 1.921 tonnes.

"At these yield levels, the growers we worked with were satisfied maize was competitive with sorghum because, while yielding less on average, the crop brought other benefits, such as a longer time after harvest to fallow before the next crop and the chance to take sowing opportunities in spring, before sorghum can be sown," Dr Robertson said.

"While the production and financial risks of maize production are higher than those of grain sorghum, growers can minimise the level of risk through agronomic and management practices, like good fallow management to maximise plant available water (PAW) at sowing.

"Judicious use of seasonal climate forecasts can aid decisions about crop selection, appropriate plant populations and other agronomic inputs."

Dr Robertson said the results of the GRDC maize project had already been widely circulated to growers and the industry in general, thanks to the strong involvement in the research of Pioneer Hi-Bred agronomist Rod Bidstrup and Goondiwindi consultants Michael Castor and Associates.