Scott McCalman and son George in a field of Sicot 619B3XF cotton at Kuranda, north of Mullaley. Pictures supplied

Almost ideal conditions have set up rainfed cotton crops across the Liverpool Plains for an excellent season.

Mullaley cotton grower Scott McCalman said the mid-December hot spell, which kicked off with two days nudging 40 degrees, was unlikely to cause too much damage as long as it didn't continue for too long.

"Cotton starts to shut down over 36 degrees, but there's nothing we can do about it," he said.

"The cotton is going well down in the valley here; it's looking really good, so it should handle it."

A fifth-generation farmer, Mr McCalman crops 985 hectares with his wife Jo and son George across three properties - Kuranda, Cincinatti and Bindaree North - near Mullaley, south west of Gunnedah, in the state's north west slopes region.

Under the Jedburgh Farming banner, they grow winter cereal, oilseed and legume crops and summer crops of cotton, sorghum and mungbeans on a three year rotation.

All machinery, including a modified bale picker, operates on 3m tracks and 12m swaths in the no-till controlled traffic farming system.

Average annual rainfall is 630mm and soils are typical of the area: black cracking clays.

Running the crimper across cover crops terminates them at 12 weeks.

Cotton is planted only every third year, in line with their focus on strict farm hygiene to minimise diseases such as fusarium and black root rot.

Cover crops play an important role in improving soil health and reducing reliance on synthetic fertilisers.

Mr McCalman has spent the past 20 years or more "pushing boundaries" with novel approaches and experimenting with different cover crop blends and timing.

"Soil health is very important in our business," he said.

"And also producing a sustainable product that's good for our business, good for our soil, and good for our future and the big picture."

After harvesting winter cereals, canola or chickpeas, fields are left under stubble until late February, then planted to a blend of temperate season cover crops which includes a cereal, brassica and two legumes that will reach anthesis around the same time.

The cover crop is terminated at 12 weeks - at the end of the vegetative stage - using a home-built chevron pattern roller crimper the McCalmans built in 2018.

This leaves a thick layer of mulch on the surface that has multiple benefits for the remaining winter fallow. It cools the soil, prevents erosion, inhibits weed germination and growth, retains soil moisture and captures up to 1mm a day from morning and evening dew, as well as feeding beneficial soil microbes and putting nutrients back into the soil for the following summer crop.

"We still use fertiliser, but we've been able to greatly reduce our reliance on synthetic fertiliser," Mr McCalman said.

"That nutrition pool we build is a cost saving to our business, but probably more importantly, it's highly plant available, and the more we do it, the better we're getting at it.

"The available nutrient pool it provides has really lifted fallow efficiencies.

"It's very exciting to see the changes that are happening to our soil health, the health of the root systems, and the water-holding capacity of the soil."

After buying Bindaree North, which has access to irrigation from the Namoi River, four years ago, the McCalmans took the opportunity this year to redevelop it, cutting the area available for cropping.

Instead of planting the usual 350-400ha of cotton, they have put in 215ha of dryland cotton, 225ha of dryland sorghum and 50ha of sorghum under a lateral irrigator.

Preparation for the cotton began in August with a pass by a Boss strip till unit to open a path for the planter through the thick mulch layer.

After having trouble with soil-seed contact, the McCalmans built a bar for the strip till unit which has a single disc opener and a heavy duty trash whipper mounted on the front.

Towed by a John Deere front wheel assist tractor, the unit was followed by an air cart towing a 5000 litre liquid cart, allowing for simultaneous application of both granular and liquid products.

This included 120kg/ha of urea buffered with fulvic/humates powder, liquid biological fertiliser containing microbial inoculum, and trace elements such as zinc, calcium and boron - as indicated in sap tests from previous crops in that field.

Using a 12m John Deere MaxEmerge precision planter pulling a 1400l tank, the cotton seed was planted from October 10 on 2m row spacings, and received another 30l of liquid biological fertiliser down the slot.

The aim was to end up with 8-10 plants per metre and 50 per cent green area.

This season's varieties are XtendFlex varieties, with two thirds planted to Sicot 619B3XF and one third Siokra 253B3XF, while Sicot 724XF was used for the refuge area.

Mr McCalman said they grew XtendFlex varieties for the first time last year and were impressed by the results.

Emergence this year was "pretty good", apart from a few patches with minor flood damage caused when 200mm of rain fell not long after planting.

Rather than top dressing urea with a spreader, Mr McCalman said he preferred to apply post-emergent foliar sprays.

Pest and disease pressure has been low, and Mr McCalman said he expected to have the cotton defoliation sprays finished by late March ready for picking in early April. Round bales will be sent to either Carroll Cotton, at Carroll, or Namoi Cotton, at Boggabri, for ginning.

While it was too early to estimate likely yields, he was hoping for 5.5 bales per hectare or more.

"It just depends on what the rest of the summer does," he said.

"In some really good years, we've been able to nudge up around nine bales in places.

"Generally, the cotton looks very good. It's got nice colour and it's obviously tapped into the nutrition pool now. We're starting to get our first flowers, so it's a week or two ahead of schedule."

This article appeared in Australian Cotton & Grains Outlook