organic vineyard floor management · 2016. 5. 31. · the bhu future farming centre permanent...

Organic Vineyard Floor

Management

A Sustainability Nexus

Dr Charles ‘Merf’ Merfield

The BHU Future Farming CentrePermanent Agriculture and Horticulture

Science and Extension

www.bhu.org.nz/future-farming-centre

The BHU Future Farming CentrePermanent Agriculture and Horticulture: Science and Extension

Download the presentations

Managing Nitrogen in Organic Vineyards - 2015

Organic / BD wine conference

Nutrient management in organic viticulture -

2015 OWG AGM

This presentation

www.bhu.org.nz/future-farming-centre/events


My Background

Commercial Horticulture Higher National Diploma,

late 1980s, UK

Managed organic vegetable farms in UK and NZ for

7 years supplying farm shops and restaurant trade

- grown nearly every vegetable there is

M.Sc. and PhD at Lincoln Uni

Now working in research with experience in

UK, Ireland, EU, USA, Uruguay, Oz and NZ

Advise a wide range of farmers and growers

The Future Farming Centre

Part of the BHU Organics Trust - based at Lincoln Uni

Not for profit - charitable trust

Old-school ag and hort research coupled to

extension / tech transfer

A quarterly free newsletter - FFC Bulletin

Just handing out knowledge:

– No preaching, no politics

– Separating snake-oil from science



The BIG picture & context

Thinking globally, acting locally

Global challenges:

– Biodiversity loss

– Excess nutrient flows, esp. nitrogen and phosphorus

– Soil degradation and loss

– Climate change

– Etc.

stockholmresilience.org


A Nexus?

The vineyard floor is where:

– Vine management

– Soil management

– Pest and disease management

– Biodiversity

Meet and have to be managed as a whole

system


A Nexus?

We want to:

– Optimise vine growth / performance

– Maximise soil health / quality

– Manage pest & diseases to acceptable levels,

ideally with biocontrol

– Improve biodiversity

For a whole bunch of reasons - both production

and environmental


The ideal system?

Have undervine and midrow plants (i.e., no bare

soil) that:

Optimise vine growth / yield / quality

Supply nitrogen / nutrients in the correct amounts

Support beneficial insects such that they control

pests (like Greening Waipara)

Assist with disease control

Improve soil health

Improve biodiversity


Context

Conventional winegrowers want/need to improve

their sustainability

The undervine area / herbicide strip is a major

issue

Undervine management in organics often copies

the weed-free approach of conventional

Is this ideal?


How to kill a soil?

The usual suspects

– Compaction

– Tillage

Herbicided undervine

– No machine or foot compaction

– No tillage

= a dead soil - compare it with the center of the

midrow

Why?


Understanding soil

Soil is by definition alive - there is no soil on

Mars or the moon - only regolith

I.e., biology is what makes soil, a soil

Therefore healthy / quality soils are biologically

active


The living soil

Soil is the most complex ecosystem on the

planet

It is typically 10 times as complex and contains

10 times the amount of life (weight and species)

than the above ground biomass

Looking after all this complexity is surprisingly

straight forward


Looking after your soil

Your soil

Feed

Organic

matter


Soil fodder

Fresh plant residues, animal dung and dead

animals (freshly dead, living things)

Diversity is the spice of life, and it makes for a

healthier soil - the more diverse the ‘fodder’ the

better the soil will be

The more the merrier (unlike people) more

fodder is better than lesshttp://www.bhu.org.nz/future-farming-centre/future-farming-

centre/information/bulletin/2013-v1/make-soil-organisms-work-for-you-

mythbusting-practices-that-do-and-don-t-work


The undervine soil

If there are no living plants undervine, then soil

health will be negatively impacted

– Herbicides

– Tillage

– Thermal

Is there a better way?

The nexus!


The Nexus

There is no starting point for a whole system

Nitrogen

Other nutrients

Cover crop plants

Bare undervine without herbicides:

– tillage & thermal

Biological control

Biodiversity


Nitrogen

It is very difficult to import N in organic systems

Compost is a very poor source of N - 1-2% total

@ 10-20% per year = 0.1 - 0.4% p.a.

Using compost for N supply will result in excess

P and K (and other nutrients)

Biological N fixation is the only sustainable long

term solution

Atmospheric, un-reactive

di-nitrogen (N2) gas

Biological nitrogen fixation by

bacteria, cyanobacteria and

actinomycetes in symbiosis with

higher plants especially the

Fabaceae (legumes)

Nitrites NO2

-

Nitrates NO3

-

Ammonia NH3

Ammonium NH4

+

Decomposers

Aerobic and anaerobic

fungi and bacteria

Reactive nitrogen in

soil organic matter

Ammonification

Nitrification

by nitrifying

bacteria

Nitrifying

bacteria

Assimilation

by plants

Biological nitrogen fixation

by free living bacteria and

cyanobacteria in the soil

Reactive nitrogen stored in living plants and animals

Assimilation

by plants

Denitrification by soil

dwelling bacteria


How vines get their N

Can only take it up as ammonium and nitrate

Small soil reserves of mineral N

The main reserve is soil organic matter (SOM)

SOM has to be decomposed to release mineral N

But…


Biologic zero

The absolute zero of soil biology

5 - 10°C, average ~ 8°C

Below this soil organisms, including diazotrophs (N

fixing ‘bacteria’) are inactive

→ Little mineralisation of N in winter and spring

→ Most mineralisation in summer and autumn

→ Very little N fixation during winter

→ Most N fixation occurs during summer and autumn


Spring N deficiency

Spring is the main time that vines will show N

deficiency due to lack of mineralisation of soil N

due to cold soil temperatures

Use foliar N fertilisers (that have been proven

under independent research / reliable

independent advice)

Foliar sprays should not be the main source of N

– Cost

– Standards


Biological Nitrogen Fixation

Clovers and legumes - undervine and/or midrow?

Optimising (not to little not to much) N supply for

vines is tricky

Midrow - side-throw mowers to blow clippings

undervines - can control N supply

Undervines - N fixed where it is needed - but may

compete with vines

In desperate need of research


Replacing P

Compost

Rock phosphate (RPR)

Other biological materials - certified

Slow release means RPR and compost must be

used pre-emptively according to soil test results


Replacing K

Compost

Other biological materials - certified

Natural mined rock

– All forms highly soluble, unlike RPR

– Potassium sulphate

– Rock dusts/flours - % K often small and slow release


Compost - illustrative analysis

Essential to test your own compost due to

variability

Element Percent Element Percent

pH 7.5 Magnesium 0.5

Carbon 30 Sulphur 0.5

Nitrogen 2 Iron 0.7

Potassium 1 Manganese 0.01

Calcium 4 Zinc 0.001

Phosphorus 0.5 Copper 0.0005

Compost can be cheaper per kg nutrient than bag ferts


Micro-nutrients: as important as NPK

Trace / micronutrients - small amounts does not

mean less important


Undervine plants / cover crops

Considerable theoretical potential

Very little research on what works

Need to balance competition with vines -

nutrients and water

It is possible for vines and undervine plants to

compete very little

– Blueberry, couch/twitch and Californian thistle

example


Undervine plants

Critical competition periods

– No competition when the vines are dormant

– Different levels of competition during growth,

flowering, bunch ripening etc

Residual effects - esp. for N where non-legumes

have taken up mineral soil N - nitrogen robbery


Undervine and midrow options

Annuals vs perennials

– Perennial - less work - mostly mowing

– Annuals - establishment, management, termination

– Perennials - less flexibility

– Annuals

• different species at different times to match needs

• Alternate with tillage / thermal / bare earth

Mix and match the midrow and undervine

The combinations are endless - needs research


Frost

Long undervine and midrow plants will increase

frost

Mowing close and cultivating = same result

– Cultivation fluffs up soil - insulation effect

Both nearly as good as permanent bare soil


Herbicide substitutes


Non-chem, bare earth, under-crop

Two physical approaches

– Mechanical

• Mowing

• Tillage / cultivation

– Thermal

• Flame

• Steam

• Electrothermal?

Mechanical vs. thermal

Mechanical is:

– Cheaper (capital and running)

– Has more choice of machines

– Tillage kills pretty much anything and everything

– But tillage can damage soil (organic matter and

structure) and more critically crop feeder roots

– Tillage struggles with stones

– Mown plants, i.e., grass, can still have a large

competitive effect

– Break up compact surface - can be beneficial

Thermal is:

– More expensive (capital and running costs)

– Has a very limited range of machines

– Does not harm the soil directly (though lack of

ground cover is detrimental)

– Will not damage crop roots - at all

– Can handle stones

– Will only kill dicot weedlings in one hit. Bigger

weeds and the monocots will require multiple

treatment - equivalent to a contact herbicide

Mechanical vs. thermal


Mechanical

Most work by having the weeding head moving

around the crop stem / trunk using:

– A spring loaded arm with a nudge bar

– A sensor system (wand) that actuates hydraulic or

pneumatic controls to move head

DearTech Hastings Hawkes Bay, DUOcut undervine scarifier


Mechanical - mowing


Mechanical - tillage

Horizontal blade

Vertical axis rotating

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Mechanic scarifying


Disclaimer

I set up a company - SteamWeeding Ltd, T/A

PhysicalWeeding - to make & sell thermal

weeders machines I have designed

I therefore have a conflict of interest

But, I’m much better scientist than I am a

businessman - so I have a pretty small conflict


Thermal: Flame vs. steam

Flame:

– Has a long ‘heat’ transfer time - difficult to get the

heat into the weeds without long hoods

– Is a (big) fire risk and it destroy plastic mulch, water

pipes in seconds

– Machines are simpler = cheaper

– Need LPG as fuel


Thermal: Flame vs. steam

Steam:

– Rapid heat transfer - can be ‘blown’ at weeds, and

around crop stem / trunks

– Very low fire risk due to presence of water, low

oxygen levels and low temps - can put out burning

material

– Unlikely to damage plastics - details important

– Uses diesel as fuel

– More expensive and uses a lot of water


Photo: Richard Flatman


Electrothermal

Back to the future - 1980s

High voltage 5-15,000 volts, low amps 1-5

Systemic weed kill - unique

Could replace roundup?

One to watch out for in future

www.bhu.org.nz/future-farming-

centre/information/bulletin/2016-v1/back-to-the-future-

electrothermal-systemic-weedkiller

Video from http://ubiqutek.com/


Mulches

Sheet mulches - plastics

– Longevity in perennial crops

– Damage from machinery etc

– Viability ???

Particulate - i.e., organic mulches

– Short lifespan - e.g., 3 years

– Not affective against creeping weeds

– Source of material - costly to transport

– Viability ???


Biological control

For vineyard floor > conservation biocontrol

through planting the right beneficial plants

– Buckwheat

– Alyssum (Cv Benthamii)

– Phacelia

Greening Waipara the

classic example

A lot of research required


Biodiversity

Limited options without impacting vines - but

still important

Best location is the midrow - planting perennials

- i.e., mixed species pasture with more than

legumes - wild flowers / forbs as well

Must be allowed to go to flower - seeding issues

Very little research

Plantings around vineyard important - but they

are not the vineyard floor.


Conclusions

Change undervine and midrow management

– Undervine - living plants as much as possible

– Midrow - improve on ryegrass and clover pasture

Outcomes

– Optimal vine growth, yield and quality

– Biological control of pests

– Improve soil health / environmental effects

– Increased biodiversity

A lot of research is required

Conclusions

Your mileage will vary: ecological techniques are

highly site specific

Variable production objectives: yield vs. quality

What works on one vineyard will fail on another

You need to be your own scientist

Try stuff on small areas to see what works for you

But, do ‘proper’ experiements: randomised,

replicated and measured.http://www.bhu.org.nz/future-farming-centre/information/bulletin/2016-

v1/understanding-biostimulants-and-biofertilisers

Organic Vineyard Floor

Management

A Sustainability Nexus

Dr Charles ‘Merf’ Merfield

The BHU Future Farming CentrePermanent Agriculture and Horticulture

Science and Extension


organic vineyard floor management · 2016. 5. 31. · the bhu future farming centre permanent...

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