Soils once plagued by water logging, compaction and crusting are now yielding 11.3 bales/hectare of cotton for one Riverina irrigated cropping enterprise. Owners Scott and Anita Hogan, have also been able to slash their fertilizer inputs by 25 per cent, improve soil structure and increase soil biology on their Coleambally farm, Wollombie, thanks to a soil rejuvenator. The family diversified into cotton four years ago with a 60ha crop and expanded to 600ha the following year. The cotton is grown on a traditional row crop layout although some paddocks have been converted to bankless channel over the past year to increase labour efficiency. A rotation of corn, wheat, rice and seed canola was modified to make way for the cotton varieties, Sicot 71BRF and 74BRF. The crop yielded an average of 11.3 bales/ha last year and was delivered to Southern Cotton’s Whitton gin. Farm manager Russell Fisher said one cotton paddock had suffered from emerging problems of compaction, water logging, crusting and poor soil structure. “We always had trouble getting the crop out of the ground so we thought this paddock would be a good one to try something different,’’ Mr Fisher said. “The predominantly clay based soil is difficult – once tilled, it will crust over, if it becomes dry it becomes hard, cloddy ground.’’

Russell and his work colleague Eugene Dore trialled the organically certified TM Agricultural three years ago, simply applying it as a tank mix at 250mls/ha to improve the soil. TM Ag uses plant extracts to stimulate indigenous soil microbes. In the first year, the TM was applied through the boom spray in the first Roundup application on a 40ha block with 4ha left as control. “I was sceptical, but it is now the only field we can consistently dig worms up all year,’’ Mr Fisher said “We have noticed our soil structure changing in that area – we can’t see any yield gains but we are not receiving any yield penalties, and we are cutting down from 500kg/ha to 350 kg/ha of upfront fertiliser alone.’’ Traditionally, 4-5 cubic metres/ha of poultry manure is incorporated on fallow country, after mulching, to feed the soil microbes. “This is followed with the fertilizer program in July-August of 200kg/ha of Granulock and 300kg/ha Urea,’’ Mr Dore said. In December, Urea is water-run in two applications at 100kg/ha. TM Ag is applied in the first Roundup application when the crop emerges in November.

“This year we water run some with the initial irrigation of the crop at 500mls/ha, followed by 250mls/ha in early January,’’ Mr Fisher said. “It hadn’t been water run before but there wasn’t any reason we couldn’t, so we trialled it. “Our theory was to get the microbes up and working in the soil as soon as possible because cotton is such a slow establishing plant, we felt soil biology working early has got to help it.’’ Mr Russell said the fertiliser rates of 200kg/ha of Granulock and 300kg/ha of Urea were reduced by 25 per cent in the paddocks treated with TM Ag last year. Deep ripping has been stopped on one paddock now into its third year of TM application, saving on fuel, machinery and labour costs. Stubble management has been practiced for six years to increase soil carbon but heavy trash loads have proven difficult. “It’s very hard with furrow irrigation system to direct drill the crop with high residues. The only crop we can manage do that with is canola, we can get the water on and off quickly so we don’t have any seed damage or water logging,’’ Mr Dore said. “In order to handle the residue, we find the best way is to mix it back in with the soil and working to a depth of 20-30cm. “Basically we rip the ground all over again mainly to get that evenness of mix of trash.’’ “You’ve just got to be open to ideas – the worst thing you can do is not try,’’ he said.

Media Release By
Kim Woods | Director
Outcross Media | www.ogacreative.com.au
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