Gunnedah-based senior land services officer, cropping, Bill Manning, said while rain had fallen recently, soil moisture was an issue.

"The dry conditions of the last two years have resulted in depleted soil moisture and very few, if any, cropping paddocks contain substantial moisture profiles," he said.

"The higher the quantity of stored moisture, the lower the risk of an uneconomic yield.

"Attitude to risk varies amongst individuals and growers facing economic pressure from the drought may take greater risk and plant summer crops on limited moisture."

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Mr Manning said moisture availability was considered to be "the yield-limiting factor" most years and determined crop inputs - particularly nitrogen - and management.

"The moisture available to the crop is made up of stored soil moisture at sowing and in crop rainfall. Rainfall in northern NSW is highly variable and unreliable and stored soil moisture increases the chance of achieving a yield that will return a profit or at least cover costs," he said.

"Given that climate forecasters are not predicting above average summer rain, crops planted on low-starting moisture may have a high risk of returning negative gross margins.

"Any stored moisture used by these crops will not be available for future crops. Growers should carefully consider the risks involved and whether moisture would be better kept for a future crop."

NW LLS said there were a number of online tools to help growers determine the risks when considering cropping, and make better decisions.

The Queensland government and the University of Southern Queensland have developed an Agricultural Risk Management (ARM) website, which contains a number of tools including CropARM.

CropARM generates discussion of growers' exposure to risk when comparing different management inputs, such as fertiliser applied, and resource-based options, such as stored soil water. The variability of the effect of each input option can be calculate alone or in combination with other inputs.

The simulations use 115 years of climate records and the APSIM model to predict the potential year-to-year variability in yields, rainfall, temperature effects and crop growth.