Next month planes will be flying over the Riverina's irrigation district spreading rice seed.

They're not just used here, over in America's Mississippi Delta, sowing rice from a plane is still very much the norm.

Forty per cent of America's rice crop is grown in the Mississippi Delta.

Pilot Dennis Gardisser explains why aerial application is vital to the industry.

"Rice production here and in the US, cannot do without airplanes."

"In fact I had a research project many years ago, there was a thought that there might be someday in the future where aerial application would kind of be taken out of the picture."

"Either by regulation or by attrition."

He says while rice sown using a combine air or disc seeder might be cheaper, planes are invaluable when its wet.

"If they think its going to be wet, they run a roller across the land and when they sow the rice aerially, the wind and the water causes the rice to move over into those grooves.

"So it actually looks like its been drilled."

"They also get better seed to soil contact, so the germination is quicker on the seed when it falls down in that v-shaped groove, because there's soil on either side of it."

Mr Gardisser who is based in a region east of Little Rock, Arkansas was in the Riverina last month helping agricultural pilots improve their rice sowing techniques.