EDITORIAL

Thank you Arthur Cameron

Hi! You will I'm sure have noted in the edito­rial of our last Top Paddock the fact that our previous editor Arthur Cameron has decided to stand aside, as editor, at least for the time being.

I would like to make note of the great job that Arthur has done over the past 3 years. I'm sure all readers of this newsletter appreci­ate his efforts and only hope that we can carry it forward in a similar manner.

The Top Paddock will now be co-edited by Rowena Eastick and myself. Thankfully Doriane Questroy will continue to do the hard work of assembling material and getting the newsletter out to you.

We would like to add a producers page to future editions so I would take this opportu­nity to invite you all to send in your articles on what is happening on your place or in your space.

The wet season has really been that and a bit more. Continuing rain is starting to lift stress levels for peanut and grain sorghum produc­ers in the Top End. However, isn't it great to live in a part of Australia where we do get rain every year.

Congratulations to management and staff at the Douglas Daly Research Farm on a well organised, enjoyable and informative Produc­ers Day. A good turnout of producers and agri­business personal were able to tour the farm and listen to and question DPI&F staff on their various research activities.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • : I1:n'tmLssQJL~3 girl : • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

Torn Price

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INTERNATIONAL CONGRESS LOOKS TO AUSSIE LAND MANAGERS

An international conference on rangelands, which will discuss the major issues affecting land management globally, is keen to hear from Australian land managers to make sure their views and experiences are heard by the world's top rangeland experts.

are a number of common themes and issues internationally.

International Rangeland Congress Themes

The VI International Rangeland Congress will • be held from July 17-23 in Townsville, North • Queensland, and will bring together scientists, land managers, extension staff and govern- • ment administrators from worldwide, includ-ing Namibia, USA, UK, Israel and Argentina. •

The theme of the congress, heading into the • 21 st century, is 'People and Rangelands: • Building the Future'. Organisers want to en­courage people directly involved in land man- • agement in an innovative or traditional way to • attend the congress. •

• A number of "scholarships" are being offered • to land managers who are involved in com- • munity participation propects such as indig- • enous land use, Landcare, or innovative ap- • proaches to managing enterprises in the • rangelands. The recipients should be able to • offer their knowledge and views in discus-sions & workshops. •

Plant invasions of rangelands Past impact, present struggle, future needs Rangelands, people perceptions and perspectives Understanding soil processes and desertification Indigenous people and rangelands Rural development, education and communication Integrating land and water management People and rangeland biodiversity Accounting for rangeland resources Modelling for better rangelands Plant functional types Sustaining an enterprise Rehabilitation of mined surfaces Economics and ecology Working for better policy Prospects for the future of rangeland people Managing grazing pressure

Issues on the agenda include sustainable land management, land degradation and diversi­fication, balancing the needs of the environ­ment with economic reality, diversification of land use, the implications of climate change, grazing pressure and total property manage­ment.

There are three plenary speakers, one of whom is Dr Tim Flannery, whose book the Future Eaters was made into an ABC TV documentary recently. Three days of concur­rent sessions will give delegates the options of choosing which papers and discussion groups will be of most interest and use to them.

More than half the world's land area, and more than 70 per cent of the Australian continent, are rangelands - areas of natural or semi­natural vegetation in which traditionally, the major land use is grazing for livestock pro­duction. The term also covers land use for mining, recreation, ecotourism and wildlife habitat. Increasingly, people are looking to rangelands to support multiple uses. There

There will also be six professional workshops of particular interest to land users and a number of congress tours, which will visit the properties of some of the best land manag­ers in the country.

Professional Workshops

1.

2.

3.

4.

5. 6.

Practical Rangeland Ecology and Defoliation Physiology Range Assessment, Rehabilitation and Monitoring Geographic Information Systems (GIS)/ Remote Sensing as Planning and Management Tools Drought Mitigation Strategies and Management - sponsored by FAO Community Landcare and Extension Cultural Heritage and Biodiversity Management

Discussions and papers at the congress will take an integrated approach to land management. Participation in the workshops enables producers to develop their understanding of how rangelands work, and provide relevant and practical information on property management.

Our Page 3 Girl

For more information and Scholarship Applications Contact:

Bronwyn Dawson IRC Secretariat Townsville Tel: (07) 4771 5755 Fax: (07) 4771 5455 Email: bronwvn@harveyevents.com.au Business Manager: Dr Gordon King Tel: (02) 9449 3670 Fax: (02) 4771 5755 Email: secretariat-irc@unsw.edu.au Website: http://irc.web.unsw.edu.au

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FARMER'S OLD AGE PENSION - IS IT FOR YOU?

A major concern for many farmers is how their retirement should be funded. One option is the old age pension. Primary producers, with their love of the land and the lifestyle, often do not view retirement with relish. Retirement from business decision making must happen - the scenario of the older generation keeping control of farm operations and the prospect of the younger generation taking over the family farm at the age of 60, is not a recommended course of action.

Options for retirement funding

Apart from the personal implications of leaving the farm and possibly the district, farmers are faced with a major concern about lifetime financial security. The best solution is by means other than farm ownership/ control. If the farmer has significant off-farm assets such as residential property, shares, investments or superannuation, there is no need to depend on the farm for security. This however is usually not the case, so if the property is to be transferred there has to be a financial arrangement with the younger generation to give the retiree the necessary security. This may be an acknowledgement of debt (loan agreement) or by a mortgage (on a mortgage or on land transferred).

Pension to relieve financial strain

With a small to medium farm, especially if it has debts to repay, providing funds for the maintenance of two farming families (younger and older) can be a significant strain, thus jeopardising farm viability. An alternative is providing financial security through Social Security and the old age pension. If the older generation is eligible for the pension, then some of this financial strain is relieved. Retirement Assistance for Farmers (RAFS) will help those who want to retire but keep the farm in the family. The Government has introduced a three - year "window of opportunity" effective from 15/9/97, for low income, pension aged farmers to transfer the

family property to the younger generation without affecting their eligibility for the Age Pension.

Gifting

If farm assets are valued over $500,000 a farmer is ineligible for the pension. To overcome this, a farmer may gift farm assets at least five years prior to the pension application. Under Social Security regulations, gifts (or "deprivation of assets") made up to five years leading up to pension application are included as assets and further gifts are deemed to earn income for the five years leading up to "deeming" provisions. Therefore, if a farmer wants to be eligible for a pension at age 65, he/she must make substantial gifts of assets before attaining the age of 60. There are disadvantages in gifting. Gifting makes the older generation financially "vulnerable", especially in the five-year period before pension eligibility. Also the gifting, if to the younger generation, can effect entitlements to family payments and Austudy for their children, as most of these allowances are based on assets owned. However, if a farmer wants the pension and the related concessions, then the gifting should be considered.

Farm Family Restart Scheme (FFRS)

FFRS is a part of a range of welfare and rural adjustment measures providing a safety net for low income farmers experiencing financial hardship. Further information about both RAFS and FFRS can be obtained from Centrelink on 132300.

Plan ahead and talk it over

A decision concerning retirement income from the farm or via an age pension is major, and in many cases difficult, for the retiring farmer to make. Retirement planning requires considerable thought and discussions. In some cases planning should start at least 10

years prior to the actual retirement date. Sadly, planning can often be poorly constructed or neglected and left far too late, with tragic consequences. When you need help with retirement planning, consult a professional adviser. This is a specialised field and the right assistance should be sought to ensure your financial security after handing on the family farm.

The Human Resources module of the Property Management Planning workshops enables participants to identify the personal skills and attributes that contribute to the business and discuss the importance of communication and succession planning. On completion of this workshop participants will be able to;

o Identify potential conflicts inhibiting effective decision making,

o Consider the major issues in developing a succession plan,

o Evaluate altemative business structures, and,

o Discuss the factors affecting inter­generational transfer.

WAYNE WOOD, PMP - Katherine Research Station

UPDATE

The hay and seed production statistics for the 1997/98 wet season reported in Top Paddock 21 contained an error in calculating the value of the hay production and a small amount has been added to the total and value of seed production.

The final figures for 1997/98 are 41,990 tonnes of hay valued at $6.006 m and 237.4 tonnes of seed valued at $1.244m.

ARTHUR CAMERON

Principal Agronomist Pasture Development

A cattle station owner was having a drink at the

bar in a pub in the Northern Terri tory. A

Yank walked in and started bragging. "Ah

come from Texas where everything big! In Texas it takes a whole week to

ride around my spread on my horse". "Hell man"

explained the station owner, "I had a horse like that once and I shot the

lazy bastard" .

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TROPICAL SAVANNAS CRC

Action Needed on Northern Wildfires

Burn early and reap the rewards later in the coming fire season - that's the message to property owners from the heads of the rural bushfire organisations of Old, NT and WA.

Russell Anderson discusses fire management after attending the latest meeting in Perth of the North Australian Rural Fire Managers Forum. This comprised of representatives of the three bushfire services and the Tropical Savannas Cooperative Research Centre.

The Forum called for more fuel reduction burns in the coming early dry season to prevent wildfires later in the year. This would require a unified approach to fire management from the three fire agencies across northern Australia.

If property owners burn off grassy fuel early this dry season, they won't have to spend as much time away from their properties later in the season fighting wildfires.

Counting the Cost

The latest satellite images from the WA Dept of Land Administration show that in 1998 late dry season wildfires burned large areas of northern Australia. The later fires tend to be fiercer, larger and more destructive than the early fires. The early "cooler" fires can actually reduce the chance of more destructive fires because they burn off the grass cover that provides much of the starting fuel for fires later in the year.

Wildfires can endanger lives and property in north Australia and tax the resources of the rural fire services.

Fighting a remote fire can mean volunteers have to leave their properties for a considerable time and when you add in

helicopters and other heavy equipment you are looking at a considerable drain on our resources. There is also good evidence that late, hot fires are having a catastrophic impact on populations of plants and animals across the north, particularly in the sandstone country of places like Kakadu National Park and the Kimberley.

Land managers need to prevent wildfires from starting in the first place - through the controlled lighting of cooler fires in the early part of the season to remove the grassy fuel. This gives the fire-fighting agencies a better chance to control wildfires and limit damage to life, property and the environment.

The North Australian Rural Fire Managers Forum established that the development of a prevention program required three components:

1. A unified approach through cooperative planning and research across State and Territory borders.

2. The enhancement of skills and acceptance of a duty of care from volunteer fire-fighting personnel.

3. A proactive campaign to keep landowners and the general public informed about the nature of fires and how to manage them.

This last goal is being pursued by the Forum in the form of a brochure and a fire awareness campaign aimed at tourists and visitors to the north during the coming dry season.

RUSSELLANDERSON Chief Executive Officer of the Bushfires Council of the NT

BULL MANAGEMENT PRACTICES SURVEY RESULTS

This project was carried out in 1994 and parts of it have already been reported in Top Pad­dock. Controllers of 28 cattle enterprises in the Top End and 58 in the VRD and adjacent Gulf properties were interviewed to determine current bull management and culling prac­tices.

Results Bull management practices in the Top EndandVRD

Average breeder herd size of properties sam­pled in the Top End and VRD respectively were 1,470 and 4,696 head. Herds ranged in size from 15 to 9,000 for the Top End and 30 to 26,000 in the VRD. Average bull per­centages used in each district were 4.7 and 5.3 with ranges of 1.1 to 9 and 1.9 to 17 for the Top End and VRD respectively.

All Top End respondents and 85% of VRD respondents practice year-round mating. Reasons offered for not control mating were largely related to bull control problems. How­ever a significant proportion of respondents believed that they get more calves because of year-round mating (11% in the Top End and 26% in the VRD). Three quarters of respond­ents in each area declared their intention to breed towards a high grade Brahman herd, with an overall preference for a Brahman con­tent greater than 80%.

Sixty percent of interviewees in each area had total control of bull purchasing policies. Most of the remainder shared control of such decisions with pastoral supervisors or their employers. Two thirds of interviewees in each area never buy bulls sight unseen. One quar­ter sometimes depend on stock agents to purchase bulls for them. Eight-two percent of Top End and sixty percent of VRD interview­ees preferred buying "in the paddock" over other methods. Approximately ten percent had experienced "the boss just dropping them on me". Half of the interviewees buy in all their herd bulls. Approximately 40% buy bulls every

year, another 40% buy bulls every second year. The remainder either breed all their own bulls (no Top End herds, approximately 23% of VRD herds) or rarely buy bulls. Approxi­mately 70% of bought bulls are Queensland­bred.

Average age at purchase and at joining in each area is two years

Age was the commonest reason for culling bulls. In the Top End it accounted for 26% of all cullings, and in the VRD it accounted for 14%. Sixty-four percent ofTop End interview­ees regularly culled for age as did 89% of VRD managers. Fourteen and ten percent from each district never culled for age. Bad temperament was the next most common rea­son for culling (20 and 13% in the Top End and VRD respectively). The next cause was bad pizzles (6% and 10%), followed by lame­ness and injury.

A docile temperament was identified as the most important of 22 selection criteria by in­terviews from both areas. Colour, pizzle size, "beefy hindquarters", testis size and overall body size were also ranked highly. Notably, price paid received only approximately two thirds the significance accorded to tempera­ment. Show results of the bull of interest or of its relatives ranked lowest as a selection criterion.

Gehan Jayawardhana, Colin McCool, David Zuill, Terry Olm

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SEED STORAGE IN THE NT TROPICS

Long periods of hot, humid weather as expe- The following are the maximum drying tem­rienced in the Top End lead to the rapid dete- peratures that can be used with safety: rioration of stored seed or grain. This par-ticularly applies to seed viability.

Factors which can influence the longevity of stored seed are conditions in the field when the seed crop is grown, how it is dried, and how it is stored.

The most important storage conditions are temperature and relative humidity.

Field Conditions

Where, when and how a crop is grown can affect seed storage life. High temperatures, and rain or dew during the crop maturing can lead to deterioration in seed quality before and after harvest. Immature seed and seed mechanically damaged during harvesting can suffer severe loss of viability during storage. Poor quality seed will lose its viability even under ideal storage conditions.

Drying Conditions

High seed moisture is the main cause of the loss of seed viability and vigour. High mois­ture causes heating, fungal activity (moulding) and encourages increased insect activity.

Seed harvested early at high moisture will generate heat if left as a bulk lot.

The seed can be spread out to dry, or prefer­ably dried by blowing unheated or heated air through the seed.

Seed Moisture Content

Over 18% 10 - 18% Under 10%

Storage Conditions

Maximum Drying Temperature (OC)

The temperature and relative humidity (RH) of the store are the most important factors affecting seed quality. Under ideal storage conditions, both relative humidity and temperature should be kept low.

Seeds are hygroscopic, that is they absorb moisture from wet air and lose moisture to dry air. Maintaining a safe moisture content for storage requires a corresponding low relative humidity, which can be achieved by-

a) Siting the storage facility in a location where relative humidity is naturally low;

b) Reducing the relative humidity to a favourable level by conditioning the storage environment with refrigeration and dehumidification;

c) Storing dry seed in impervious sealed containers ego sealed tins or drums, thick plastic bags or bottles.

Rules of Thumb are:

Unheated air is effective if the relative humid- • ity of the air is lower than the equilibrium mois­ture content of the seed. This is not usually

When seed moisture content is between 5% and 14%, each 1 % reduction in moisture content approximately doubles seed storage life.

the case in the Top End, except during the dry season.

Heated air allows quicker drying. Most seeds • can tolerate up to 50°C for short periods, but too high a temperature will kill the seed.

When storage temperature is between ooe and 50°, each 5°C decrease in storage temperature approximately

doubles seed storage life.

LENGTH OF STORAGE

The conditions required to safely store seed depend on the period of time required for storage.

1) Shortterm storage (1-9 months, 1 dry season)

Good quality seed can be safely stored under the following conditions:

a) 30°C-50%.RH. b) 20°C-60% RH. c) Other combinations of tempera­

ture and relative humidity similar to the above, such as 20°C-50% RH which approximates normal room air conditioning.

2. Intermediate storage (18-24 months, 2 dry seasons)

Successful storage can be arranged using the following conditions:

a) 30°C-40% RH. b) 10°C-60% RH. c) Other combinations of temperature

and relative humidity similar to the above.

3. Long Term storage (up to 10 years)

Long term storage can be achieved by cold dry conditions, between 0-5°C and 30-40% relative humidity.

These conditions can be obtained only in a well insulated storage room with refrigeration and dehumidification equipment. Specifications and de­signs for this type of seed store are

available in the literature.

DPIF have stored grass seed at 10°C in seed stores at DDRF and Berrimah Farm for 6-1 0 years with minimal loss of viability.

OPEN STORAGE

Seed kept at the ambient temperature and humidity in the Top End is vulnerable to rapid deterioration in seed viability_

Farmer Bill was worried about his best looking bull so he called the

vet. "He's just not

interested in the cows" seidB;11.

"Well" said the vet "give him this mixture

twice a day and see how he goes".

Farmer Bill was delighted with the

result. "Whats in the mixture

the vet gave you"? asked his neighbour

Ian. "Don't know what they

call it" Replied Bill "but it's green and tastes like vanilla" .

9

Ambient climatic conditions at two selected sites in the NT are in Table 1 below:

MONTH

Site J F M A M J J A S 0 N 0

DDRF

9 am RH 82 92 81 69 64 77 66 63 65 64 68 71

3 pm RH 56 67 61 61 41 39 41 41 24 28 37 43

MaxT 34 32 34 35 33 31 31 34 36 37 38 36

MinT 24 23 23 20 17 13 14 16 18 21 23 23

Katherine PO

9 am RH 76 80 76 65 56 54 50 49 50 56 60 70

3 pm RH 52 54 49 37 34 31 27 24 23 27 32 43

MaxT 32 32 32 32 29 27 27 30 34 36 36 34

MinT 24 24 23 21 17 15 13 15 20 24 25 25

The combinations of temperature and rela-tive humidity, even in Katherine are generally Summary over the 30°C-50% RH or 20°C-60% RH for safe short term storage of seed. Seed will not usually retain its viability

from one wet season to the next under Most seed in open storage ie a shed in ambient conditions in the Top End of the the NT, particularly grass seed will not NT. remain viable from one wet season to the next. Seed stored in this way will often The minimum requirement for carry - over have nil viable seeds when tested in No- seed is an air conditioned room. This will vember or December prior to a planned be perfectly adequate to hold good seed sowing. for 1 dry season with minimal loss of vi-

ability. Hygiene

For longer - term storage, a well con-Seed storages need to be kept clean, and structed cool room with controlled tem-free of spilled seed that will encourage insect perature and humidity is required. and rodent pests (rats and mice).

The seed storage area should be free of ARTHUR CAMERON ledges, corners, and sharp angles where in-sects and rubbish can collect. It should also be air-tight in case the seed needs to be fu-migated to control pests.

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FERTILISER TREATMENT COMPARISON ON IRRIGATED PEANUTS

An experiment was conducted to determine the effect of fertiliser placement treatments on the yield of irrigated peanuts, with result­ant implication for the crop's gross margins.

Trial Description: The trial was designed to provide information on three key areas of peanut nutrition; base fertiliser placement, the effect of additional applications of iron chelate and the use of gypsum to supply cal­cium. Growers were unsure of the limitations on yield when deciding to broadcast or band, base fertiliser. The initial comparison was to assess the effects on yield in comparing single band vs double band vs broadcast. The water extracted from the 001100 aquifer can contain calcium compounds; this has both positive and negative effects. Removal of gypsum and application of chelated trace elements were attempts to maximise benefits

Details: Sowing Date: 30,31/5/98

from this situation.

Soil Type: Ruby Blain, Northcote Key Gn2 .11 (Dr4 .51). This soil type is a member of the red earth Great soil group. The soil is amongst those considered most suitable for irrigation in the Top End.

Location: Douglas Daly Research Farm approximately 245 km (by road) south of Dar­win. Latitude 13 degrees 50 minutes south, longitude 131 degrees 12 minutes east.

Growing Season: This investigation is a part of studies into utilisation of the dry sea­son period experienced in the Wet/Dry trop­ics and as such received very little rain until the final stages. The dry season begins around April and the first storms are usually experienced in October. Total water applied

Paddock History: 97198 Wet Season; Forage Sorghum (as a green manure) 97 Dry season; Ley

Seed Rate:

Fertiliser used:

Land Sale Value:

96/97 Wet Season; Ingrid Pearl millet (seed crop), yielding approxi mately 750 kg/ha. The number of seeds planted; 178,1001 ha. Seed rate per metre of row was 16. Germination of the seed was 64% Population counts on the 23/6/98 averaged at 92,666/ha HI Fert Goldphos 20 @ 180 kglha 0:16:0:20 MOP @ 60 kg/ha. Gypsum Librel Chelated Trace Elements. Uncleared and unimproved, approximately $1 00-$150/ha Improved approximately $400-$500/ha

was 6.8 MUha, which was supplied by overhead (centre pivot) irrigation.

Special Notes: The hand harvest was completed two weeks before the actual bulk harvest (delayed by rain). This also caused large digging loss and high levels of aflatoxin in the bulk crop, hence the low yields and low payment per tonne as seen in the gross margins.

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Results:

Fertiliser Yield Uha Broadcast 6.55 Double 6.57 No Gypsum 6.88 Single 6.69 (LSD(p<0.05) 0.713 (p-value 0.714

Iron Treatment

No 6.65 Yes 6.69 (LSD (p<0.05) 0.566 (p-value 0.888

Dry Matter kg/4m row 2.55 2.50 2.76 2.56 0.620 0.783

2.714 a 2.472 b 0.201 0.022

Jumbo(%) Grade One (%) Grade Two (%) 51.56 10.44 7.20 48.40 10.89 8.52 51.54 10.81 7.41 50.36 10.95 7.12 9.427 2.342 1.870) 0.856 0.959 0.351)

50.691 50.241 3.566 0.785

0.65 0.89 1.374 0.706

7.64 7.49 2.077) 0.873)

Means with different letters are significantly different. Statistic figures are indicated in brackets

Gross Margin:

Gross margins vary enormously even within • crops of similar yields, due to other influences such as aflatoxin penalties. Table 1 presents • the gross margins for the highest yielding plot, the lowest yielding plot and the actual machine • harvest yields for the total area (trial and bor­der). Some pOints that need to be stressed when assessing these margins are; •

Table 1:

Item Income High(Hand) Actual(Machine) Low(Hand)

YieldUha

7.8 2.98 5.1

Water use efficiency is shown in Table 2: Costs High(Hand) Actual(Machine) Low(Hand)

Gross Margin! ha High(Hand) Actual(Machine) Low(Hand)

Both high and low were individual, hand harvest yields, of one plot only. The actual harvest yield was down graded due to aflatoxin. Due to severe digging problems the actual yield harvest loss averaged approximately 3.3 tonne/ha. All yields are on cleaned dry weight.

Total ($/ha)

6195.90 1716.45 3034.15

3128.97 2498.27 2775.68

3066.93 -(781.82) 258.48

Table 2:

Water Use Efficiency Hishest Yielding Plot Actual Machine Harvest Lowest Yielding Plot

YIELD kg 7800 2980 5100

mm 680 680 680

WUE 11.5 4.4 7.5

Conclusions:

There was no significant difference between each base treatment. This is not surprising as peanuts have mychorrhizal roots and there­fore are more efficient scavengers of nutri­ents. The surprising result is that the no gyp­sum treatment did not show any significant difference in yield or grade. Calcium is im­portant to kemel and pod production. Insuffi­cient calcium results in "pops" or unfilled shells. Blain soils have a low CEC but combined with the calcium present in the water and the avail­able calcium in the soil the pegs and pods were able to successfully absorb adequate amounts in this situation. The applications of iron chelate had no effect on yield in this situ­ation, however it had a small but significant, negative effect on dry matter. Extrapolating out values this equates to 1 tonne per hec­tare less dry matter when iron was applied.

At reasonable levels of soil nutrition there is little or no benefit in banding base fertiliser. At this stage it is not recommended to reduce application of gypsum until more work has been done on soil levels and bore monitor­ing. A general application of trace elements appears to adequately supply the plants needs, as they are able to successfully ex­tract trace elements even in slightly alkaline conditions. The preferential formulation would be chelate mix rather than a sulphated mix when fully irrigating a dry season crop.

Chris Ham, Irrigated Crops Agronomist

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UNDERSTANDING WOOD 2

Heartwood, Sapwood, and Natural Durability

It stands to reason that the most important part of a tree (to the tree itself that is) is the out­side. It is here that the tree is protected from mechanical, chemical, and climatic damage by its bark. On the inside of the bark is the phloem, a spongy layer which carries energy in the form of sugar down from the leafy crown to the rest of the tree, including its roots. In­side this again is the most remarkable tissue of all, the cambium. The cambium is a deli­cate film, only one cell thick, which almost completely envelopes the woody part of the tree and ingeniously produces different types of cells on each of its two surfaces at the same time. On its outer side it adds to the inner bark or phloem, while on the inner side it pro­duces the woody cells which make up the great bulk of any tree. The wood being pro­duced in the current year is especially impor­tant because most of the upward movement of water and nutrients from the soil takes place through it. The cambium has to add to its own length as well while all this is going on because the circumference of the tree is in­creasing all the time. The life force of the whole tree, then, is contained within the cambium.

The outside of the tree, as we have seen, is the most important part as far as the living organism is concerned. Once it has been cut down, of course, the position is altered. Some properties of wood which make it im­portant to man are attributes of the inner wood or heartwood, while others are attributes of the outer wood or sapwood. In the case of fuel - still the biggest end use of wood - it doesn't much matter. It depends more on the density of the wood. The denser a wood, the better for fuel it is likely to be. A property of heartwood which is of interest to man is its colour. Hence its use for panelling, furniture, turnery, and craftware. The pale and uninter­esting sapwood is useful only to the extent that it may offer a contrast to the more positive

colour of the heartwood. A property of sapwood, on the other hand, is its higher per­meability to liquids compared with heartwood,(i.e. it allows liquids to pass through more easily) therefore it can be treated with water soluble preservative chemi­cals.

How is it that wood within a tree can change its properties as the tree grows? The an­swer lies in the fact that, as a tree increases in diameter and its wood volume expands, it does not need all of its volume for the stor­age of carbohydrates and water. So, the cells of the inner part of the tree die and become repositories for a wide range of chemical sub­stances loosely called extractives. It is these substances which give most heartwoods their colour. They may also affect the permeability of cell walls and thus the drying characteris­tics and dimensional stability of some spe­cies.

In other words these substances may physi­cally obstruct the movement of water mol­ecules through cell walls. In practical terms this means that the heartwood of some spe­cies is more difficult to dry than the sapwood and once dry, it will shrink or swell less with changes in atmospheric humidity.

phloem ba.k

Perhaps the most important property of these chemical substances, however, is that many of them are toxic to biological enemies of wood. A prime example in the Northem Terri­tory is Cypress pine or Callitris intratropicia. This species is resistant to the giant termite Mastotermes darwiniensis. It also means that the heartwood of some species is resistant to the attack of decay fungi and the heartwood of a few species is very resistant. There is a common misconception here. When we talk of a particular species of wood having a natu­ral durability rating of so-and-so, we are re­ferring to the ability of its heartwood to resist the attack of decay fungi in the ground. As a rule of thumb, however, a species ranked moderately durable in the ground would be classified durable above the ground, and so on. It needs emphasising here that all sapwood is classified as perishable. That is to say, if it is placed in the ground, it will be destroyed by decay fungi within two years.

Commercial timbers around the world are given natural durability ratings based on a universal system of testing. Stakes of 50x50 mm heartwood are placed in the ground in randomised plots within test areas called graveyards. They are inspected once a year and assessed by knocking sharply on two adjacent sides with a wooden mallet. If they do not fail, the soil is dug away and the stakes are given a rating for decay. It should be noted that these ratings have been derived from a wide range of results.

Durability ratings

Perishable « 5 years)

Non - durable (5 - 1 0 years)

Moderately durable (10- 15 years)

Durable (15 - 20 years)

Very durable (> 25 years)

The ratings are based on graveyards in sev­eral different locations and cover a range of climates, topographies and soil types. An important point to note is that the ratings ap­ply to small stakes, so a fence post could be expected to last longer in the ground. An interesting point in connection with natu­ral durability is that a species with a high rat­ing in its native land will not necessary be as durable when grown in another country. Part of the answer to this, lies in the fact that dif­ferent countries have different species of fungi in their soils.

So much for heartwood and natural durabil­ity, but what about the rate of formation of heartwood. To put this another way, do all trees of the same age have approximately the same depth of sapwood? Far from it. There are wide sapwood species and there are narrow sapwood species. As far as utili­sation is concerned, a wide sapwood spe­cies mayor may not be a disadvantage. In the case of furniture timbers, for example, it is mostly a disadvantage as the coloured heartwood is generally sought after, though some very attractive furniture is made from the sapwood of pine species. The paler col­our permitting a wide range of stains and other sophisticated finishes to be used. There are a few species which have pale coloured heartwood so it is difficult to tell where the sapwood ends and the heartwood starts. Most of the ash type eucalypts are like this. Whereas the Northem Australian native, Cooktown Ironwood or Erythrophleum chlorostachys has a deep red-brown col­oured heartwood.

Parts of the text of this article has been ex­tracted from "New Zealand Timbers" by N.C. Clifton.

Beau Robertson, Agroforestry

15

16

UPDATE ON THE NATIONAL LIVESTOCK IDENTIFICATION SCHEME (NLlS)

The NUS is a dual tagging system based on identifying cattle with a Breeder tag and a Transaction tag. The Breeder tag identifies the property of birth and is permanently at­tached to the animal. The Transaction tag is attached just prior to sale or slaughter to iden­tify the last property on which the animal was kept.

Technical Developments for Breeder Tags

Two dimensional barcode devices have been found to be unsatisfactory as breeder devices.

Only radio frequency devices can meet the required criteria for field retention and ma­chine-readability. The devices will be in the form of a button ear tag containing a micro­chip. These are expensive at $5.00 to $8.00 each.

Technical Developments for Transaction Tags

The performance of 2 dimensional codes on wrap around tail tags has not been proven conclusively yet, but they are expected to work because of the short period between application of tail tags and reading at abat­toirs. The 2 dimensional codes are less likely to work on ear tags and ratchet tags used as transaction tags. This means that while ear tags have been accepted in most states as an alternative to tail tags they will not be ma­chine-readable.

Implications for national uptake of NLIS

The use of breeder tags is voluntary. There is no significant change to the Transaction Tag system, which is already in place. Issues of carcase feedback to breeders and the commercial and private nature of this infor­mation are unclear. The threat of limitations on trade to Europe is unclear. If Victoria pro­ceeds with the adoption of breeder tags in 1999 then it will effectively be a trial run for the NUS.

The management value of NUS tags needs to be assessed by cattle producers. Uncer­tainty about what technology will be used on transaction devices will delay uptake by the processing sector.

Implications of Northern Territory uptake of NLIS

The transaction tag system operating in the NT in 1999 will remain the same as the sys­tem operating in 1998 except that producers will have the option of using an ear tag instead of a tail tag. Stranger tags will still be blue in colour but will carry the same property identi­fier code as station owned stock.

The hide retrieval system will continue to iden­tify the brands of cattle with granulomas de­tected at slaughter.

The same tail tag numbers will continue to be used by stations, but in future they will be re­ferred to as a property identifier code (PIC). A station may have one or more property iden­tifier codes. Producers may continue to use existi ng stocks of tags.

Current Status

Livestock identification in the NT is based on the use of brands, waybills, property identi­fier codes (tail tag numbers) and tail tags

The system has been proven to be practical, efficient and cost effective. Any new system needs to be technically sound, practical for on property use and cost effective.

The implementation of a breeder tag system in Victoria in 1999 should allow many of the technical issues to be put to the test. Only NT cattle producers can determine if the system would be practical or cost effective under lo­cal conditions.

KelSmall Livestock Identification Co-ordinator

BENCHMARKING A 'BOnOM LINE' APPROACH FOR NT GRAZIERS

Northern Territory graziers are being encour­aged to adopt benchmarking techniques to better understand their bottom line and de­termine business strengths and weaknesses.

Every producer looking to increase profitabil­ity should look to critically appraise the over­all performance of their business.

The northern Australia Bizcheck pilot program -which started in March and now has some 12 participants - was all about using avail­able business data to analyse business per­forrnance.

While some producers may feel uneasy about benchrnarking, Bizcheck in reality is some­where between a "gut feel" analysis and a sophisticated program, providing a quick and easy snapshot.

Bizcheck is part of a much larger Business Skills and Best Practice (BSBP) program currently being developed by Meat and Live­stock Australia and a producer based steer­ing committee. The committee includes NT representative Ned McCord.

One of the most pleasing aspects is the fact that Bizcheck not only allows producers to map their own performance, it allows them to compare performance against other produc­ers in the region and even against others in the same industry in another region.

May presentation at the Katherine Meat Profit Day (MPD), provided producers with a valu­able insight into the Bizcheck program and how it could be applied to their business. The speech was one of a range of topics address­ing the issue of Business Management.

The day also included research presenta­tions, displays and demonstrations on the top­ics of: Market information; Land and pas­ture nutrition; Cattle management and breed­ing; and Business management. These pres-

entations were conducted on a rotational ba­sis to allow producers the opportunity to par­ticipate in discussions on each of the topics.

Held under the theme "Secure your Future" the MPD was held at the Henry Scott Rec­reation Centre in Katherine on 8th April. Pro­ducers attending the event also had the op­portunity to participate in the annual general meeting of the Northern Territory Cattlemen's Association which was held at the same lo­cation on the following day.

The AGM program covered a range of issues including beef industry R&D and marketing, plus a keynote address from the President of the Cattle Feedlot Association of the Philip­pines - Renato Tayag outlining the trade from a user's perspective.

NTCA Organising Committee Chairman, Peter Moffatt said he believed it was in the interests of all producers to understand ways of benefiting from the available management information.

He said benchmarking was just one of the many techniques available to producers look­ing to better understand their business opera­tions.

Peter Moffat also stated that the MPD pro­gram gathered together a range of informa­tion that showed producers how, at a practi­cal level, improved on-farm management can be achieved.

"It was a unique event that will not be repeated again in the Territory this year", he concluded.

Steve Banney, Bizcheck Northern Australia Coordination Meat & Livestock Australia Ltd And Peter Moffatt NTCA

17

18

PASTORAL MARKET UPDATE

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At a glance, the 1 st to 15th April provided • another good fortnight of 14,831 head. The total number of cattle exported through the Port of Darwin to date for 1999 is 77,004, up • 33,099 on this time last year.

The figure of most note this fortnight was the 6,283 head to Indonesia. This brings the to- • tal number of live cattle exported to Indone-sia through the Port of Darwin for 1999 to 15,150, only 4,464 short of last years total of • 19,614. Although still a long way from the heady numbers of 1997 (244,701), even the most pessimistic must view this improvement as an indicator of recovery.

Record Beef Exports for March

Korea, 8,400 tonnes compared to 770 tonnes for the same period last year.

Canada, 4,000 tonnes, bringing the total for the first quarter to 12,500 tonnes - double the same time last year.

Taiwan, 3,600 tonnes, up 27% on the same time last year.

The contrast to these success stories is Japan (our largest market in 1998), down 2% on the last year. The reasons cited are the economic recession and intense US competition.

Australian beef exports of 87,000 tonnes in March were up 11 % on February and 24% on the same period last year. This reflects continued high beef slaughter, particularly cow beef for the US market, thanks to a large de­gree to the low A$.

Source: Prepared by NTG Office of Resource Development and the Pastoral Division of NTDPIF

The best performers for March were:

• The USA who exceeded 30,000 tonnes for the first time since 1993.