tim salmon - integrated orchard management

Integrated Orchard Management

Prepared by: Tim Salmon

Teaming With Microbes

16/10/2014

2014 AMS 40th Anniversary Industry Conference proudly presented by




OR

Why we apply mulch instead of profiling and prune instead of mechanically hedging.


Outline

1. Why “Teaming With Microbes”?

2. Farm history

3. Strategy

4. Results


Why “Teaming With Microbes”?

Soils Part 3: Good soil is teaming with life

One teaspoon of good soil contains;

One billion bacteria

Several metres of fungal hyphae

Several thousand protozoa

A few dozen nematodes


The role of soil microbes

Decompose organic matter and release nutrients/produce humus

Release nutrients from soil mineral particles

Fix atmospheric nitrogen

“Feed” nutrients and water to plants

“Tie up” nutrients preventing some from leaching

Produce plant growth stimulants (vitamins, hormones, enzymes)

Protect roots from invading disease pathogens and nematodes

Improve soil structure

Detox – remove wastes produced in farming process


Why not team with soil microbes?

Without a healthy biologically active soil our farming systems are

increasingly dependent on us to provide the right inputs at the right time in

the right quantities to maintain production. More;

• Monitoring

• Intervention

• Energy

• Money

• Waste (pollution)

• Insight & understanding


Requirements...not too hard

Enough food (something containing carbon)

Adequate moisture

Air (not compacted => top soil)

Liveable temperature (not too exposed)

Freedom from harmful soil conditions (salts, extreme pH,

pesticides...)


Requirements...not too hard

Enough food (something containing carbon)

Adequate moisture

Air (not compacted => top soil)

Liveable temperature (not too exposed)

Freedom from harmful soil conditions (salts, extreme pH,

pesticides...)

Many of our practices are either actively or passively counter-

productive with regard to soil health


Farm history to 2011

Soil replacement trial following millennium drought about 2004 – too costly

Trial using round bailed hay 2006

Purchased profiler December 2007 – persistent dry conditions

By 2010 obvious(?) production declining

Phytophthora

Reduced canopy density – reduced hedging requirement

Increasing fertilizer requirements

By 2011 lost root volume approximately 60m3/ha – shallow soils

Penetrometer tests...


Production history 1991 – 2013

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Strategy development

Exposed roots revisited

Importance of light reaching the orchard floor

Importance of canopy architecture

To profile or to mulch?


Exposed roots revisited

Exposed roots = lost root volume = loss of buffering

moisture

nutrients

Best soil lost or moved further away from tree

Tree’s energy requirements increased(?)

Biological activity of remaining soil is lower

Nutrient cycling compromised – more fertilizer

Disease likely hood increased


Importance of light reaching the orchard floor

GROUND COVERS:

Importance of plants in supporting the soil foodweb

Diversity, diversity, diversity....(more resilient system,

mycorrhizae)

Incorporate carbon in soil (mulch/compost surface only)

Water infiltration, reduced runoff of nutrients

Aeration (combat compaction)


Importance of canopy architecture?

Tree height is important –

Crop protection

Shade orchard floor

Tree’s energy requirements(?)

Canopy architecture contributes to root exposure(?)


To profile or to mulch?

Cultivation strips carbon (soil biology)

Cultivation damages soil structure particularly if moisture not

optimum (compound risk) – managing soil moisture is costly

How much material is available to profile - potential to expose

sub soil (recovery of ground covers, temperature, run-off, root

volume)

Slope

Damage to macadamia roots


Our strategy:

1. Make soil health a priority - better manage future costs

2. Direct cut grass, leaf and displaced mulch to cover roots

3. Mulch over exposed roots - offers reduced risk, many benefits

to soil health and lower cost(?) when compared to profiling

4. Postpone hedging - selectively prune where shading is

extensive


What we did:

Since 2011 prior to 2014 crop (last mechanical hedging 2009) –

prune to raise irrigation lines whole farm, selective limb removal

trial, tree removal trial, coppice trial & chipped everything

2011 purchased zero turn mower and stopped using herbicides

2012 purchased mulch spreader & prior to 2014 crop applied

25m3/ha of mulch, now 40m3/ha, 60m3/ha looks optimistic =

(100L/tree, 160L/tree, 240L/tree)


After application of 25+m3/ha mulch 2012 & 2013

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Is our strategy successful?

Other variables

Crop nutrition – frequency increased, total ==

Irrigation - significantly improved DU

Context

Previous crop(s) – bounce?

Season – most severe?

Too soon to tell; a one-off or first of trend?


Is our strategy successful?

Other indicators

Canopy density improved

Phytophthora reduced

Penetrometer improvements

Soil Foodweb analysis

The value of baseline measurements

Some way to go but encouraging

Nitrogen supply: “Low nutrient cycling and availability. Need

more protozoa and beneficial nematodes to cycle nutrients”


Afterword

Don’t have to replace lost soil in one go to get some benefit – response to

mulch may be slower than soil(?)

Covering exposed roots will provide immense benefit but may be short lived

if consideration not given to causes – need to do more to “tie down” mulch

Sufficient light to support the growth of some ground covers is essential for

longevity and resilience

Three low cost ways to check your objectivity -

Soil health card

Soil foodweb analysis

Benchmarking


Recommendations & Acknowledgements

Soil foodweb analysis – www.soilfoodweb.com.au

“Teaming with Microbes” Lowenfels & Lewis 2010

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