Food production: from first domestication of crops to the present …ewds.strath.ac.uk/Portals/50/Global Food Security/suii... · 2016-06-13 · Food production: from first domestication

Sustainable deintensification? Geoff Squire

A B

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SUII, University of Strathclyde Glasgow, 24 May 2016 1

Graham Begg, Cathy Hawes, Pete Iannetta, Ali Karley

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content

main trajectories - four phases of intensification

status of the maritime croplands – phase 4

implications of raising yield

deintensification – how, where

biotech crops

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yield gap - global examples

grain yield (t/ha)

temperate wheat-barley

Squire, in press

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the four phases of intensification …..

starting 1940s …

• realisation and reorganisation

• intensification

• levelling and regulation

• decline and degradation?

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“great quantities of aquavitae”

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0

1000

2000

3000

1940 1960 1980 2000 2020

a b

3 2 1

total grain

output (kt)

Wight 1784

Original data: SG National Statistics

nitrogen input Scotland

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0

50

100

150

200

250

1940 1960 1980 2000 2020

year

2 3 1

kt nitrogen

Original data: Fertiliser Practice

pesticide

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PAI

PAI = pesticide area index

Original data: SASA

0

1000

2000

3000

4000

0

1

2

3

4

5

6

7

8

1950 1970 1990 2010

PAI a

nd

HA

I

year

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status of the maritime croplands

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divergence due to intensification

• all fields can now be

ranked on nominal

intensity scale

• soil ‘poorer’ where >2 in

5 WW or 1 in 5 potato

0

2

4

6

8

10

1940 1960 1980 2000 2020

yiel

d p

er u

nit

are

a (t

ha-1

)

year

s barley

w wheat

intensity map for arable-grass

• survey of >100 fields, 2007

• agronomy and biophysical

(soil, plants)

• SCRI/SAC (SRUC/Hutton) • later data on landscapes

and cropping history • revisited • repeated, in part, 2014

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field survey to assess status

Publications: Hawes et al. 2010; Valentine et al. 2012; Squire et al. 2015, etc.

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divergence of trajectory

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14

16

18

20

22

24

26

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0.4 0.6 0.8 1 1.2 1.4

intensity index

L1

H1

H3

H2 L2

L0

soil clay content

(%)

75 fields, 5 crop-years

entering a fourth phase ?

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1940 1960 1980 2000 2020

N

I II III

grain

?

• yield levelling • yield gap widening • some soils degrading • pesticide increasing

SUII, University of Strathclyde Glasgow, 24 May 2016

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implications of raising yield

raising yield

• take people out of famine or hunger

• increased pollution / degradation (soil

disturbance and nitrogen)

• move from food to industrial crops

• encroach on other land to increase

profit

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• (production decoupled from local food consumption)

• yield levelling, yield gap widening

• use efficiencies – variable, but pesticide less effective

• upper soil degrading in some sub-systems

• massive weed shift to grass and reduction of

uncommon plants

• but system is still responsive and still diverse in terms

of number of crops and mean intensity

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…. is phase 4 beginning ?


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deintensification …..

deintensification

• already happening in some areas

• will be forced by soil degradation

• definitely more N fixation (legumes)

• coupled with new high value products

(beans4feed, bean beer)

• less bulk production

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how to deintensify?

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 20 40 60 80

rank

intensity index (N, P, PAI)

then decide on overall strategy

general deintensification

reduce to a threshold

common framework (A1)


limits and safe ranges T3.5

A B

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the green line is a process or function varying over time

need to define ranges A and B

within A, no special work or attention is needed

between A and B, work or remediation has to be applied

outside B, the system eventually collapses

soil nitrogen not limiting and not

polluting

soil nitrogen limiting crop production

soil nitrogen above critical

pollutant load N

availabil

ity

too little nitrogen to support plant life

soil too polluted (toxic) to grow plants

A

B

work 1

work 2

Bii

Bi


• six course rotation: Potato – Winter wheat – Winter barley – Winter

oilseed – Beans – Spring barley

• 42 ha, 6 fields

• split field design

Winter wheat

Potato

Spring barley

Spring beans Winter barley

Winter OSR

Centre for Sustainable Cropping

the sustainable cropping system

• nitrogen cycling

– fertiliser down to 75%, to be

gradually reduced further

– better nodulation and fixation

in legume crop

– clover undersowing

(additional N input in SB)

• organic matter and soil

condition

– compost addition (35t/ha)

– straw incorporation

– non-inversion tillage (10cm)

– tied-ridging (potatoes to

reduce erosion)

• crop varietal – testing under low input

conditions

– look for increased nutrient use efficiency

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a role for biotech crops ?

biotech crops

• risk vs risk-benefit

• herbicide resistance – wide scale field

trialling

• blight tolerance in potato – small scale

field plots in two countries

• need for context setting and upscaling

27 SUII, University of Strathclyde Glasgow, 24 May 2016

pesticide reduction in oilseed rape?

herbicide tolerant oilseed rape

- major on-farm trials 2000-2004

- herbicide sprays down from 2.2 to 1.1 but small overall reduction in pesticide

- no effect on yield, negatives for biodiversity

- coexistence with non-GM almost impossible

no advantage to north-temperate cropping systems


pesticide reduction in potato?

blight tolerant potato

- two small plot-scale trials, Ireland and Netherlands

- fungicide sprays down to 20% of current in potato

- no effect on yield compared to fully sprayed and neutral for biodiversity (soil metagenomics and arthropod food web)

- major overall reduction of pesticide e.g. to 75% in low-input sequences, to 90% in high input

- where would it have most effect?


location of fields (B3)

potato fields red, other arable in black

all workings at scale of individual fields

(right) convert to grid for illustration


estimation of fungicide (B3)

proportion of crops in field / grid

estimate mean pesticide per crop from national census

for GM replace with trial site data

GM

GM

Conv.

Conv.

low input

high input

red/orange – high fungicide yellow – mid blue / green – low fungicide

5 x 5 km grid


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next?

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whole-system modelling and design

crop and agronomy

life forms

ecological processes

optimised outputs and

ES

networks of effect

Dexi software in action

store and flux models

• comparative assessment

• design of improved systems


deficiencies in understanding

• the problem of in-field corroboration (survey)

– cost / time

– skill shortage

– continuity

• ‘limits of concern’ unclear for many major variables

• N fixation and how to increase it

• crop ideotypes for adverse conditions

• unification of data (national statistics)

34 SUII, University of Strathclyde Glasgow, 24 May 2016

a suite of capabilities ………

• innovation stream – from science to outreach and practice

• scientific capability in agroecology, systems, soils,

biodiversity, genetics and breeding, etc.

• test platforms – Centre for Sustainable Cropping

• 3 experimental farms – lowland, upland, arable, stock

• in-house statistics, system modelling, decision aids

• farm networks across Scotland to track current trajectory

• outreach and education e.g. LEAF Innovation Centre, Living

Field www.livingfield.co.uk

• >50 EU and wider collaborations for global impact

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………seamless knowledge chain


http://www.livingfield.co.uk/

Documents

Food production: from first domestication of crops to the present …ewds.strath.ac.uk/Portals/50/Global Food Security/suii... · 2016-06-13 · Food production: from first domestication