These trials were done on Willow Tree properties "Berwicks" and "Yarrabah". Windy Station at Pine Ridge also just picked its first cotton crop, which was a success, despite several seasonal challenges.
The properties join a small number of farmers who have been growing cotton successfully in the region for the past five years.
Tackling one of the toughest growing seasons in years, the growers had to deal with limited soil moisture at planting, a cold start to the crop and high insect pressure late in the season.
Monsanto regional business manager Paul Brady said the huge contrast in weather conditions really tested the cotton.
"For the first 60 days the crops suffered through 45 nights lower than 11 degrees then they were hit with a flood and the heatwave through Christmas and January," Mr Brady said.
"Things didn't start to turn in the growers' favour until February."
Being dealt a difficult season made the trial even more successful, with the crop showing its promise despite constant setbacks.
"The fear down that end of the valley is you wouldn't be able to manage the cotton through the season," he said.
"It's shown cotton is a fairly resilient plant and compensates well when the conditions turn in its favour, while sorghum yields suffered in the same harsh weather."
Geoff and Neil Barwick, "Yarrabah", and James Arnott, "Berwicks", will grow another two crops in the three-year trial, giving Monsanto long-term comparative data on cotton's ability to grow in colder weather.
With an average yield of about five bales a hectare, the Barwicks' cotton ended up being some of the better performing dryland cotton in the Namoi Valley.
Mr Arnott's cotton averaged about two-and-a-half bales a hectare.
"Once we get it ginned and we have data to look at it will give us an opportunity to consider whether we have the right varieties and row configuration and whether planting needs to be altered, then we'll keep refining it every year," Mr Brady said.
"Hopefully we'll have enough evidence to show new growers the management practices used so they can make educated decisions on the farm rather than take a punt with a new crop."
Mr Brady said Monsanto was committed to making cotton a long-term summer crop option for Liverpool Plains farmers, who rely on sorghum as their main summer rotation.
About 600ha of Sicot 71BRF was grown at Windy Station to break up the rotation and deal with shattercane in sorghum.
"We purchased MR43 seed that had shattercane problems then grew sunflower crop to control it and went back to sorghum last year, but shattercane appeared in the paddock again," Romani Pastoral Company manager Keith Harris said.
Mr Harris said cotton offered a very competitive gross margin compared to other summer crops, making it a profitable option.