growers@sgcotton.com.au Roger Tomkins - Greenmount Press

More documents

Recommendations

Info

Nutrition feature… control (no stubble) treatments were included. The incorporated treatments and a control were tilled weekly prior to all pots being irrigated to near field capacity. Results Field study (Experiment 1) SOC increased in the 0–30 and 30–60 cm depths of soil, but no significant change was apparent below 60 cm (Figure 1). Between 0 and 60 cm depth, SOC increased by about 1.24 tonnes C per hectare per year (or 4.4 tonnes of CO equivalent (eCO ) per 2 2 hectare per year). The increase in SOC was much greater in the 30–60 cm depth in the soil profile. Controlled environment study (Experiment 2) SOC was slightly lower where the soil was tilled compared with no tillage (Figure 2) – but the three treatments were not statistically different. Had the tillage operations been more vigorous, deeper or more often, or the experiment continued for a longer period, the loss of SOC may have been greater. At the end of the experiment, only 22 per cent of the stubble-C applied to the soil surface was retained by the soil, compared with incorporating the stubble, where 54 per cent of the stubble-C was retained. Also, of high importance is the effect of stubble addition on soil micro-organisms which use the carbon from the stubble as their energy source. The soil microbes that can fix nitrogen from the atmosphere (outside of the legume/rhizobia association) do so using the energy released as they decompose crop stubble. Incorporated stubble supported a greater amount of freeliving N fixation compared with the surface stubble treatments. About 20 per cent of the stubble-N was lost where the stubble was applied to the soil surface stubble treatments, but total soil N increased by more than 50 per cent where the stubble was incorporated. Over three drying cycles, water loss was 10 per cent lower in the surface-applied stubble treatment, compared with the stubble incorporation treatments, as the soil was disturbed. Water loss averaged 2.5 and 2.7 mm/day for the respective treatments. Discussion Barcoo… Enjoy a cool holiday this year, and at a great rate Significant increases in SOC can occur where management practices encourage retention of the stubble-C added to the soil, FIGuRE 1: SOC at two profile depths Barcoo is a superbly appointed lodge at Dinner Plain in the heart of Victoria’s high country. This year round playground offers trout fishing, magnificent scenery, great restaurants, peace & quiet and other cool activities. • 4 bedrooms (all with queen size beds) • 3 bathrooms • Spa pool • Fully equipped with all mod cons • Sleeps up to 16 GREAT VALUE FOR LARGE OR FAMILY GROUPS Further details phone 1800 670 019 or www.dinnerplain.com 32 — The Australian Cottongrower August–September 2012
and minimise the loss of stubble-C. To achieve this, tillage needs to be minimal (and shallow), with soil disturbed only when necessary to apply fertiliser, to destroy pupae and to incorporate stubble. Dryland farmers may choose to retain stubble on the soil surface in order to retain more soil moisture, but they do so at the expense of long-term soil health and SOC levels. In the control treatment with no stubble addition, tillage roughened the soil surface which may have promoted water loss to a small extent. The mulch effect provided by the surfaceapplied stubble appeared to slow water loss. Field experiments indicate that soils managed with minimum tillage (permanent beds) and with stubble incorporation can sequester substantial amounts of atmospheric CO 2 . Incorporated stubble retained more than twice as much stubble-C than surface applied stubble (54 per cent 22 per cent). While a small amount of N contained in surface-applied stubble was lost, the incorporated stubble promoted substantial biological N fixation. Stubble applied to the soil surface reduced water loss by almost 10 per cent. These results help to explain the rates of C sequestration reported in previous experiments where all stubble was incorporated. This research helps to define better management practices that will assist growers to improve soil health and enable their cropping systems to be more resilient, profitable and environmentally responsible. Acknowledgment: Funding provided by the Cotton CRC and CRDC. Contact Ian Rochester E: ian.rochester@csiro.au Nutrition feature… FIGuRE 2: SOC in soil subjected to regular tillage compared with no tillage in Experiment 2 The Key to Effective & Safe Foliar Fertilisation For truly effective foliar feeding of cotton, use Barmac’s innovative CoRoN controlled-release technology. Take Control of Foliar Feeding With CoRoN Technology Contact your Barmac representative for details on how CoRoN can improve your cotton crop. (07) 3727 3000 or visit www.barmac.com.au August–September 2012 The Australian Cottongrower — 33
Page 1 and 2: August-September 2012 www.cottongro
Page 3 and 4: In this issue... 2012 Cotton Grower
Page 5 and 6: The trouble with buying old technol
Page 7 and 8: We’re with you from the beginning
Page 9 and 10: BE READY FOR ULTIMATE PRODUCTIVITY
Page 11 and 12: Roger Tomkins: 0409 100 036 Louise
Page 13 and 14: Field proven irrigation power John
Page 15 and 16: 16th Cotton Conference roundup AFTE
Page 17 and 18: Delegates may have found out more t
Page 19 and 20: You’re in control of your future.
Page 21 and 22: 2013 FARM STUDY TOURS For More Info
Page 23 and 24: Water Matters… Series supported b
Page 25 and 26: Valley ® Strongest in the industry
Page 27 and 28: Nutrition feature… Impact of nitr
Page 29 and 30: (ADVERTORIAL) Local Trials Show Bio
Page 31: SOIL organic carbon (SOC) is an imp
Page 35 and 36: WORLD COMMODITY WATCH India Specula
Page 37 and 38: documented, the Chinese state reser
Page 39 and 40: 3100% Australian Cotton 3100% Austr
Page 41 and 42: for the position between the gin st
Page 43 and 44: The trial crop has yielded around s
Page 45 and 46: FIGuRE: 3 Relationship between EM34
Page 47 and 48: Temik, is in short supply and is sc
Page 49 and 50: The joys (or otherwise) of tractor
Page 51 and 52: in Australia), when it finally erup
Page 53 and 54: Germinating ideas By CSD Extension
Page 55 and 56: Evaluation of insecticides for cont
Page 57 and 58: NEW Holland’s most powerful tract
Page 59 and 60: Students visit cotton districts CAL
Page 61 and 62: District Reports… Central Queensl
Page 63 and 64: Darling Downs The 2012 cotton seaso

growers@sgcotton.com.au Roger Tomkins - Greenmount Press

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?