Re­ly­ing on rain

Inside a di­verse crop­ping op­er­a­tion at Dalby

Warwick Daily News - South West Queensland Rural Weekly - - Front Page - Dan­nika Bonser [email protected]­ral­weekly.com

IN 1904, the Dalby town coun­cil and their sub­ter­ranean drilling team were over­joyed when, at

870m, they struck wa­ter. The small Queens­land town was look­ing to es­tab­lish an arte­sian bore sim­i­lar to other nearby cen­tres such as Moree and Mitchell, and what they struck was min­eral-rich and a ther­a­peu­tic 38C.

For the next 34 years Dalby was a place where lo­cals and tourists in­dulged in “tak­ing the wa­ters” – a na­tional health fad in the early 1900s that was thought to be rem­edy bod­ily aches and pains.

But for Dalby farmer Wayne New­ton, “tak­ing the wa­ters” is not about drilling down, but rather in­ter­cept­ing wa­ter to fill dams – some­thing that has been in short sup­ply in re­cent years.

With no ac­cess to bore wa­ter or al­lo­ca­tions from the Con­damine River, he can only use what comes from the sky.

Much needed Oc­to­ber rain­fall of about 100mm has tem­po­rar­ily quenched the thirsty soils where he farms on the Dar­ling Downs flood plains, 200km north­west of Bris­bane.

An­nual rain­fall to­tals have been well down al­most ev­ery season since 2013, with

50mm cracks fre­quently seen in the heavy clay soil.

Wayne said al­though the cracks could be a me­tre deep and looked se­vere, they were a nor­mal func­tion of the ex­pan­sive Ver­tosol clay soil. He just needs them to fill with wa­ter.

“The beauty of it is when you get heavy rain the cracks lit­er­ally fill from the bot­tom,” he said. “The wa­ter runs down to the bot­tom of the cracks and soaks out into the ground in be­tween the cracks – it’s like fill­ing a bot­tle from the top.”

“When the soil gets wet it swells and the cracks close. It swells both ver­ti­cally and hor­i­zon­tally and ev­ery­thing closes up, and that helps then keep the mois­ture in the ground un­til the crop uses it, and once the crop uses it the cracks open up again ready to take in the next rain.”

SUM­MER LOV­ING

WAYNE puts in both sum­mer and win­ter crops, but says the most im­por­tant are the sum­mer ro­ta­tions of cot­ton, sorghum, mung­beans and maize.

Be­ing in a sub­trop­i­cal climate means crop­pers on the Downs are less re­liant on in-season rain, but need to have soil wa­ter pro­files rel­a­tively full be­fore sow­ing.

The area’s heav­i­est clay soils store up to 250mm of plant avail­able wa­ter, with the lighter ones closer to 200mm.

To shore up wa­ter sup­ply for thirsty crops like cot­ton, the New­tons built two 1000-me­gal­itre turkey-nest dams in the late 1990s.

The com­pacted clay-wall dams store wa­ter that is “har­vested” from nat­u­ral drainage lines run­ning across their prop­erty. The wa­ter is in­ter­cepted as it runs across the flats to­ward the Con­damine river, and pumped into the dams.

There is now a mora­to­rium on in­fra­struc­ture in­ter­cept­ing wa­ter this way, un­der the Mur­ray Dar­ling Basin Plan.

“When it comes to over­land flow, be­cause we’re lim­ited to when we have the wa­ter, we can do it – it’s not like we’re tak­ing it out of a river – there’s may be only four or five days a year we can pump it,” Wayne said.

In or­der for the wa­ter to run, the cracks in the clay must fill up first.

“When things are rea­son­ably dry mostly we don’t see much run-off un­til we’ve had over 100mm rain,” he said. “At the 100mm point there’s a bit of wa­ter start­ing to lie around on the coun­try. Once you get an­other storm with an­other 25–40mm that’s when you start to see the wa­ter run­ning, and that’s what we’re see­ing now.”

PUMP IT UP

ONCE the wa­ter is run­ning, the New­tons can pump 200 me­gal­itres of over­land flood­wa­ter a day, mean­ing that five days of pump­ing will fill the dams for the next season.

Of their 630mm av­er­age rain­fall, well over half comes in sum­mer.

“It’s a highly vari­able climate we work in, and the dis­tri­bu­tion of that rain can be quite spo­radic,” Wayne said.

“Cer­tainly it’s not un­usual to go through July to Septem­ber with very lit­tle or no rain.

“We take rain when we can get it.

“Build­ing stor­ages for wa­ter is just one of our responses to the climate we have up here.”

Storm cells in sum­mer were un­pre­dictable and area-spe­cific, the multi­gen­er­a­tional farmer said.

“There might be a big storm travel through the dis­trict, and if you’re right un­der­neath it you get the rain, and if you’re on the edge you smell the rain.

“Over the years I’ve seen seven inches come down in a cou­ple of hours. Well that makes a lot of wa­ter.”

De­spite get­ting too much rain be­ing a more com­mon prob­lem than the op­po­site, the past few years have been ex­cep­tion­ally dry.

Un­til mid-Oc­to­ber, Dalby has hardly seen enough rain to fill the cracks, let alone the dams. The area recorded

42mm in the nor­mally wet months of March to May, and

72mm be­tween Fe­bru­ary and Oc­to­ber.

But a lot can change in three weeks. The skies opened in early Oc­to­ber, dump­ing 105mm. At the New­tons’ place the clay cracks filled quickly, but only small amount of run-off was cap­tured for stor­age.

Ac­cord­ing to Wayne, their two dams are now 15 per cent and 75 per cent full, mean­ing more sum­mer rain is needed for the sum­mer crops.

❝climate

It’s a highly vari­able we work in, and the dis­tri­bu­tion of that rain can be quite spo­radic.

— Wayne New­ton

CROP TOPS

WA­TER, weather, prices and a myr­iad of other fac­tors mean that de­cid­ing crop­ping ro­ta­tions in the sub­trop­i­cal climate can go down to the wire.

“We don’t have fixed ro­ta­tions, we’re very flex­i­ble. What we plant is driven firstly by avail­able mois­ture, and then what the re­turns are go­ing to be,” Wayne said. “Cot­ton is one of our most prof­itable crops, but then you’ve got to have a good pro­file of mois­ture if you want to grow it on dry land, or ir­ri­gation wa­ter if you’re go­ing full ir­ri­gation.”

Cot­ton is now mak­ing good re­turns for Aus­tralian farm­ers, and the New­tons are well ser­viced by three lo­cal cot­ton gins to process their har­vest.

In a good year they can pro­duce sev­eral thou­sand bales, with the yield vary­ing from three to eight bales/ha on dry­land pad­docks and 10-12 bales on ir­ri­gated ones.

“Cot­ton prices are pretty good at the mo­ment – they’re north of $600/bale. That’s good. We’ve sold cot­ton for as low as $300/bale be­fore, but any­thing above $500 is rea­son­able,” Wayne said.

Hav­ing wa­ter se­cu­rity for the cot­ton-growing season is para­mount, mean­ing the stor­age dam lev­els at early Novem­ber are cru­cial when de­cid­ing how much to put in.

Sow­ing is any­where be­tween Oc­to­ber and De­cem­ber.

This year Wayne, who farms with his wife Bev, son Greg and daugh­ter-in-law Lisa, has put in 320ha, with the Oc­to­ber rain com­ing in the nick of time to en­cour­age a larger plant­ing.

In the Dar­ling Downs re­gion cot­ton isn’t taken off un­til April-May, but in the in­terim sorghum and mung­bean crops are har­vested.

“The beauty of the long growing season means that if it has a tough start, cot­ton is such a tough plant and it can hang on for rain later in the sum­mer. The sub­soil mois­ture keeps it go­ing and then if you get the rain, you get the yield,” Wayne said.

Un­der­pin­ning their crop­ping sched­ule is sorghum, this year the New­tons aim to put in up to 800ha.

PHOTO: DAVID MARTINELLI

WORK­ING SMARTER: Dalby grain grower Wayne New­ton is a Farmer of the Year nom­i­nee.

Wayne New­ton hold­ing chick peas.

PHO­TOS: DAVID MARTINELLLI

A flock of emus on Wayne New­ton’s fam­ily prop­erty at Ranges Bridge 240km west of Bris­bane.

PHO­TOS: DAVID MARTINELLLI

RAIN DANCE: Dalby grain­grower Wayne New­ton on his prop­erty 240km west of Bris­bane.

Mr New­ton said de­cid­ing crop­ping ro­ta­tions in the sub­trop­i­cal climate can go down to the wire.

This year the New­tons will plant 800ha of sorghum and 320ha of cot­ton.

Emus wan­der­ing the pad­docks on the New­tons’ prop­erty.

Wayne New­ton.

Chick­peas are part of the New­tons’ win­ter ro­ta­tion.

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