Things are happening

Dear Reader

Welcome to another issue of the PINT newsletter. In this issue we take a look at a few things going on around the NT with Plant Industries. Firstly, a brief wrap up of the Northern Territory mango industry’s annual forum. As the title reflects, the event covered a lot of territory from plant breeding and crop manipulation, fruit quality, sourcing free and sound financial advice, occupational health and safety and a whole lot more.

Also included in this edition are preliminary results from the nitrogen project being supported by the Federal Dept. of Agriculture, Fisheries and Forestry. There are some interesting early-stage findings that reinforce the value of cover-cropping in our tropical annual farming systems. Nitrogen efficiency gains have many positive benefits for both the environment as well as reducing the overall cost of nitrogen inputs to farmers. We will maintain regular updates on this project as it delivers its results, and will provide subsequent advice around improved farming practice.

Finally, let’s not forget the red centre, where we have a new staff member on board in Doug MacDougall. Doug will be working principally in the revitalised date project which has been funded by the Rural Research and Development Corporation.

Please read on. I encourage mango growers to check out the upcoming events section and get along to the highlighted activities.

Regards

Contents / Things are happening
Mango forum covers a lot of Territory
Cover crops tie up nitrates in the wet season
Introducing Doug MacDougall, Alice Springs
Useful Links
Upcoming events
Estimating Mango Harvest Maturity - Darwin
9th Australian Mango Conference

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Mango forum covers a lot of Territory

The NT mango industry research, development and extension forum held recently at Knott’s Crossing Resort in Katherine attracted 33 participants, including a number of the Territory’s largest mango production entities. Issues covered entailed:

  • A harvest season overview.
  • Varietal improvement programs which included an AMIA update on National Mango Breeding Program (NMBP) releases, a brief on Ken Rayner’s upcoming varietal releases and; the NT DPI&F Rootstock & scion trial at Katherine Research Station.
  • An outline of the Rural Business Support service now available to NT primary producers.
  • Reporting on progress and outcomes of group-based extension activities in the NT Mango Industry.
  • Post-harvest R&D which comprised results from scoping the effect of Vigor-Cal™ and Biomin™ on lenticel spotting, as well as activities focussed on better understanding the attributes of ‘B74’ mango to further improve its commercial viability.
  • Market access issues involving horticultural export development via the Port of Darwin, as well as using area wide management systems to eliminate the current reliance on post-harvest treatments against fruit fly in Katherine.
  • Updating on biosecurity issues such as mango malformation disease, and new biosecurity protocols for mangoes. Note: articles on these subjects will appear in coming newsletters.
  • A presentation on the Crop Manipulation project that has recently been awarded by HAL.
  • Primary Industries Safety Advice program and the free audit and planning service now available to farmers.
  • A summary of HAL’s overall portfolio on Mango RD&E and;
  • a brief on the NT Mango Advisory Panel, what it is, who’s involved, and what it is doing for the local industry.

Two field trips, one to inspect the rootstock/scion trial at Katherine Research Station, and other to Peter Marks’ Ballongilly farm were well-received.

The 1 ½ day forum at Katherine was characterised by a retreat type atmosphere fostering a high level of industry and service provider interaction. The assessment was that further forums would be periodically held in Katherine due to its ongoing development a major mango production region.

Dr Cameron McConchie points out the attributes of one of the rootstock/scion combinations at the KRS trial site to Ross Maxwell of Jabiru Orchards.

Marie Piccone of Manbulloo pursues an animated discussion with Peter Marks during the field tour to Ballongilly.

Cover crops tie up nitrates in the wet season

By: Stuart Smith, Senior Extension Officer, NT DPIF.

Preliminary results from the cover crop trials are showing that nitrate accumulates in plots with spray-out fallows as opposed to plots which contain cover crops such as Jumbo™ or Fumigator™ sorghums or lab-lab. Results from soil tests show that nitrates are elevated at both 0-10cm and 10-20cm depths where there are no cover crops to utilise and immobilise nitrogen. In addition, water samples from Full Stop™ wetting front indicators taken from depths of 20cm and 40cm, have shown higher nitrate concentrations in fallow plots than in plots containing cover crops. This means nitrate-laden water is moving down through the soil profile where there is no root extraction to prevent it. This heightens the risk of production of the greenhouse gas nitrous oxide by soil bacteria which then diffuses into the atmosphere. The logic is that cover crops short circuit this by utilising nitrate over the wet season. Results from the direct collection of nitrous oxide gas from the soil in specialised receptacles remain to be analysed. However, once this completed, we will have a better idea of the precise effect cover crops have on not only nitrous oxide production, but also carbon dioxide and methane.

Also of interest was that ammonium levels were very low in all samples, including from fallow plots. This suggests that during our wet season, ammonium is rapidly converted into nitrate through a process known as nitrification. This is undesirable, as nitrates are rapidly lost through leaching while ammonium ions are not. It appears that cover crops are necessary to help arrest this loss.

Measurements of organic carbon have shown no appreciable changes over the course of one season. It may be that longitudinal studies are needed to determine the influence of cover crops on soil organic carbon levels over time.

There were no significant differences in the biomass production of two types of sorghum cover crops, Fumigator ™ and Jumbo™. Both produced 8.4-8.6 tonnes per hectare of dry matter. Biomass production from Lab Lab was considerably less (4.6 tonnes per hectare), but this legume may have an advantage in breaking down more quickly in the soil. The thick and tangled growth habit of Lab-Lab was very effective at protecting the soil from erosion and had the added advantage of suppressing weeds. Lab Lab’s concentration of plant nutrients per unit dry matter was higher than sorghum for a number of elements, but because of its lower overall dry matter, total extraction of some nutrients from the soil was less than sorghum.

Lab-lab (with a few stray sorghum volunteers) at “The Sweet Life” farm, Alphatonia Road, Humpty Doo. 22nd February 2013. Sorghum cover crops flank either side of this plot.

Cover crop growers should now be working their cover crops into moist soil, to enable decomposition prior to the sowing of the first dry season crops in late April / May. This may be a time where much nitrogen is lost from decomposing cover crops, and consequently our research will see us continue to take measurements until the next planting season begins, so we can properly understand what is occurring in the system.

IntroducingDoug MacDougall, Alice Springs

Doug has recently moved to Alice Springs from Melbourne to take up the role of Horticultural Field Assistant working in the date and bush tomato projects with Plant Industries. He has spent nearly twenty years as a horticulturist at the Werribee Zoo where he grew plant material necessary to sustain the diets of the many different animals held at the facility. He also maintained many of the different exhibits.. Doug has previously holidayed in central Australia and hopes to further explore the landscape during his stay in Alice – welcome Doug.

Useful Links

APVMA

Public Chemical Registration System

APVMA Permits

APVMA – Dimethoate Review

  • APVMA – Fenthion Review

Bureau of Meteorology services

Weekly climate note

Madden-Julian Oscillation

Horticulture Publications

DAFWA

Mango Information Kit

NT Primary Industries Agnotes and Fact sheets

Primary Industries Publications – NT DPIF

Upcoming events

Estimating Mango Harvest Maturity - Darwin

Upcoming workshop at Berrimah Research Farm, 30 April 10.30am to 12.30pm. Features instruction around the mechanics of fruit ripening, understanding heat sum calculations and how to use them in association with other harvest maturity determination skills.

9th Australian Mango Conference

The conference is being held in Cairns and Mareeba from the evening of Tuesday, 14 May to Friday, 17 May 2013. Program andregistration details are available on the AMIA website:

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