Irrigated cereal production put to the test - Greenmount Press

Irrigated cereal productionput to the testBy Donald McMurrich, AgCentral Grain SystemsI’m going to start this article off withplenty of excuses, so you can alreadytell there was nothing really to bragabout by way of exceptional cereal yieldsin our 2005 irrigated experiments. Thesetrials formed part of the Super Crop Challengeinitiated in Australian Grain magazinein 2004. We are searching for wholefarm system approaches to help maximisegrain yields and returns.For the first six months of last year wewere in drought. This was coupled with along 2004–05 summer crop growing seasonresulting in slightly higher water useby the irrigated cotton phase of our productionsystem. This meant that throughthe winter crop decision-making periodof March, April and May, we were in aquandary as to whether to even plant thewinter crop.With some crops in the ground, andno rain predicted, it was decided to startwatering up some fields. Then it started torain, and rain some more — for the nextfour or five weeks when the bulk of thecrop should have been sown.By the middle of August the fields weredry enough to work on again but by thenwe decided that these ‘late’ crops shouldbe taken through on the ‘cheap andcheerful’. We reasoned that if it becamehot in late October — an extremely criticalperiod of winter cereal plant growth— the extreme heat would shut the plantdown.These very wet conditions meant thatsome of the farmers I have been workingTABLE 1: Variety trial 2005Variety Yield t/ha % ofcontrolGS 02 (NZ) 8.37 124LPB 01 (France) 8.34 123LPB 02 (France) 8.06 120LPB 04 8.01 119GS 01 (NZ) 7.77 115GS 03 (NZ) 7.59 112LPB 03 7.06 105LPB 05 7.04 104HRZ 04 6.94 103Giles (Aust’n) 6.75 100HRZ 02 6.36 94Sowing accuracy and the resulting crop configuration from the Sulky one-pass system.with around Gunnedah, on the LiverpoolPlains, didn’t get much of a crop in.Of the crops that were planted andwatered up, subsequent water-loggingcaused very inconsistent planting configurationsand patchy fields. It was decidedthese crops should not be ‘pushed’ as theyield potential for these fields was alreadygreatly reduced.So by August, with only a small numberof fields with any potential, and with mostof the farmers I have worked with for theprevious three seasons out of the game, itwas clear the crops were never going tobe blinders.Sulky one-pass systemGiven the difficult 2005 season we didwhat was possible at sowing time. For thefirst time we introduced a ‘Sulky’ one-passestablishment system.This system incorporates the trash fromthe cotton crop, creates a tilth and pullsthe soil from one metre hills to two metrebeds. It packs it all down firmly with apacker roller and sows the cereal crop at12.5 cm (five inch) row spacings.This gave us 14 rows of wheat on topof the bed. Coupled with the increase inplant population, this greatly improvedthe Crop Canopy Index or the crops’ abilityto intercept light.This machine really proved its worthlast season as it was confronted with soilwhich could only be described as concreteat the end of the dry spell, to the othervery wet extreme later in the season. Itwas working in the wet soil conditionsbefore any of the standard sowing gear.During the growing season we followedthe growth stages of the plants and introducednutrition, plant growth regulatorsand fungicides where necessary.Last season more replicated work wasdone to see if there were varieties with agreater genetic potential to yield underthese high input systems (Table 1).We are essentially modeling our systemon a European/New Zealand style of production.Is there an advantage in havingaccess to international genetic material?The short answer is ‘yes’. In 2005 weintroduced both European and New Zealandgermplasm with some impressiveresults in small replicated plots. Table 1shows that it may be possible to increaseyield by 24 per cent by changing varieties.Given that variable costs remain prettymuch the same, it means a 24 per centincrease in gross return.The seed companies involved wereGrainsearch and Longreach and theCSIRO (HRZ) High Rainfall Zone plantbreeding program.In coming years the higher yieldingvarieties will be available with specificagronomic packages, which if followedclosely, should allow farmers to replicateand improve on current trial successes.18 — THE AUSTRALIAN COTTONGROWER APRIL–MAY 2006

The money endThese Super Crop demonstrations have revealed that the dollarreturn per hectare can be improved through this style of highinput production system. The dollar return per megalitre can alsobe enhanced.Table 2 shows that the highest yielding irrigated crop in a verydifficult 2005 season was 8.0 tonnes per hectare. Coupled witha very low commodity price, the gross margin was much lowerthan the previous season at $357 per hectare.But on a positive note a return per megalitre of $178 wasstill achieved. This is a very encouraging figure as it suggestsvery strongly that as we refine our high input crop establishmentand agronomy — and with access to higher yielding, high inputcereal varieties — a return of between $300–$500 per megalitreis achievable.There is also the rotational benefit to following crops to beconsidered.The Cotton Catchment Communities CRC will further investigatethe benefits of high input/irrigated wheat production.This article first appeared in Australian Grain March–April 2006, andwas contributed by Cotton Growers Services.For more information contact Donald McMurrich on 0427 799 500.TABLE 2: Cereal gross margins and returns permegalitre under the high input production systems,2003–05Crop history Cotton 1 Fallow 2 Fallow 32003, 8.60 t/ha $180/t2004, 10.24 t/ha $175/t2005, 8.03 t/ha 145/tIncome $/ha 1548 1792 1164Variable costsEstab./seed 210 210 210Starter fertiliser 110 30 55Herbicide 20 10Plant Growth Regulator (PGR) 21 22 22Spring nitrogen 200 172 170Fert. application &micronutrients 85 60 45Fungicides 60 60 55Irrigations x 2 100 100 100Harvesting costs 158 185 150Total variable costs ($/ha) 964 849 807Gross margin ($/ha) 584 943 357Water use (ML/ha) 2.70 1.50 2.00Return ($/ML) 216 629 178CROP HISTORY & LOCATION NOTES1 Wheat following a 2002–03 cotton crop at Boggabri;2 Wheat following a February 2004 ploughed out cotton cropon the Breeza Plain; and,3 Wheat following a 12 month fallow at Warren.APRIL–MAY 2006 THE AUSTRALIAN COTTONGROWER — 19