Impact of clim

ate change on plant grow

th and nutrition

-Small Study G

roup 2018-

1University of Vienna (BOKU), Department of Natural Resources and

Life Sciences, Austria 2University of Novi Sad, Faculty of Agriculture, Novi Sad, Serbia 3University of Florence, Departm

ent of Agrifood Production and Environmental Sciences, Italy

Workshop 2018

SERBIA FOR EXCELL, W

ORKSHO

P, 2018

Lukas Koppensteiner 1, Anh Mai Thi Tran

1, Tijana Narandžić

2, Carolina Fabbri 3, Milena Daničić2

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•The increasing w

orld population is putting stress on rising demands for crop

production. By 2050, global agricultural production w

ill have to double to meet the

future demands.

•

Clim

ate projections predict changes in atmospheric C

O2 level, tem

perature and rainfall pattern.

•There is high concern about direct im

pact of climate change on agriculture.

•

Uncertainties related to representation of higher C

O2 level and tem

perature dem

onstrate that further knowledge upon effect of clim

ate change on agriculture is needed.

•To get better insight to im

pact of climate change on agriculture, different aspects of

agricultural production, such as crop growth and nutrition, m

ust be investigated.

Ge

ne

ral intro

du

ction

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Objective

• To discuss

aspects, benefits,

disadvantages and

the practical

applicability of

spectral measurem

ents and selected vegetation indices in plant production and clim

ate change research. Spectral m

easurements

¾radiation reflected by a given vegetation cover is detected

¾used to calculate algorithm

s called “vegetation indices” (VIs).

Vegetation indices num

erous applications – e.g. measure plant properties, predict yields, detect w

eeds and diseases, investigate effects of clim

ate change on crops.

1. Spectral measurem

ents and selected vegetation indices in plant production and clim

ate change

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General inform

ation on radiation ¾

light reaches an object => radiation is absorbed/transm

itted/reflected ¾

spectral measurem

ents detect the reflected radiation Spectral characteristics of plant canopy ¾

many plant properties have an im

pact on spectral reflectance of crops at certain w

avelengths

wavelengths < 700 nm

: low reflectance; light absorption by chlorophyll

wavelengths > 700 nm

: high reflectance; not used for photosynthesis

Spectral measurem

ents

Distinct spectral reflectance curve of green plant canopy (M

ulla, 2013)

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Differences betw

een platforms

altitude, spatial and spectral resolution, return frequency

Satellites ¾

return frequency, spatial resolution, cloudy conditions ¾

estimation of crop biom

ass and yields on a regional scale

Aerial system

s ¾

transition platform, cloudy conditions

¾real-tim

e site-specific agricultural managem

ent decision making

Proximal system

s ¾

active and passive spectrometers

¾on-the-go detection of plant properties

Platfo

rms fo

r con

du

cting sp

ectral

me

asure

me

nts

Conducting spectral

measurem

ents using a handheld spectrom

eter (AS

D, 2010)

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Selected vegetation indices N

DVI (N

ormalised D

ifference Vegetation Index) ¾

reflectance ratio at near infrared (~ 790 nm) and red bands (~ 670 nm

) ¾

useful for assessing LAI and plant biomass

¾soil reflectance at low

canopy densities affects ND

VI results

ND

RE (N

ormalised D

ifference Red E

dge) ¾

reflectance ratio at near infrared (~ 790 nm) and red edge bands

(~ 720 nm)

¾sensitive to high levels of chlorophyll content

CC

CI (C

anopy Chlorophyll C

ontent Index) ¾

based on NDVI and N

DRE

¾used to m

easure plant N nutrition

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Goal

Estim

ating plant N status via C

CC

I and CN

I (Canopy N

itrogen Index) by combining

spectral measurem

ents and crop models for various crops (w

heat, maize, potato

and sugar beet).

Current B

OK

U project on spectral measurem

ents and VIs (C

CCI)

Conducting spectral

measurem

ents at BO

KU

Relationship betw

een CC

CI

and CN

I in wheat (Fitzgerald et al., 2010)

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Goal

gather knowledge on the typical responses of plants to the various effects of

climate change and their im

pacts on crop production A

pproach com

bining available long-term and large-scale data on historical w

eather as well

as indirect measurem

ents of various plant canopy characteristics based on spectral sensing Im

provement to resource use efficiency

Optim

ised farm m

anagement based on spectral sensing (fertilization, irrigation,

plant protection measures)

Spe

ctral me

asure

me

nts an

d V

Is in clim

ate ch

ange

rese

arch

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Challenges

¾spectra of plant canopies are influenced by various factors

¾m

any VI applications need cultivar and site-specific calibrations

¾only few

farmers have access to spectral data of their crops

Opportunities

¾optim

ized farm m

anagement strategies

¾increase in farm

profitability ¾

reduction in environmental pollution

¾better estim

ation of the climate change effects on crops

Challenges and opportunities of spectral m

easurements

and VIs in plant production

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Research questions

• How

was the “behavior” of clim

ate in the last three decades in Thai Nguyen province,

the mountainous area in the N

orth of Vietnam (the study area)?

• Did historical clim

ate conditions have positive impact on m

aize production over the past 30 years in the study area?

2. Climate change and crop grow

th

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http

s://catalog.flatw

orld

kno

wled

ge.com

/bo

okh

ub

/26

57

?e=b

erglee_1

.0-ch

05

_s05

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Source:

http://ww

w.colorado.edu/geography/class_homepages/geog

_3251_sum08/

Source: http://cafef.vn/thai-nguyen-nhieu-noi-ngap-lut-nghiem

-trong-do-anh-huong-cua-bao-so-6-20170825111338504.chn

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1980

1985

1990

1995

2000

2005

2010

2015

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Precipitation (mm)

Ye

ar

Fe

bru

ary to

Ma

y Ju

ne

to S

ep

tem

be

r O

ctob

er to

ne

xt Jan

ua

ry

Nguyen, R

enwick and M

cgregor, 2014

Annual precipitation during 1980-2015

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12001400

16001800

20002200

24002600

2800

3000

3200

3400

3600

3800

4000

4200

4400

Observed grain yield (kg/ha)

Total annual rainfall (mm)

Equationy = a + b*x

Weight

No W

eighting

Residual Sum

of Squares

5.0942E6

Pearson's r--

Adj. R-Square

-0.45953Value

Standard Error

BIntercept

2022.01333155.75017

Slope1

--

12001300

14001500

16001700

2800

3000

3200

3400

3600

3800

4000

4200

4400

Observed grain yield (kg/ha)

Total solar radiation (hours)

Equation

y = a + b*x

Weight

No W

eightingR

esidual Sum

of S

quares4.33886E

6

Pearson's r

--A

dj. R-S

quare-0.24312

Value

Standard E

rror

BIntercept

2423.2143.74018

Slope

1--

7980

8182

83

2800

3000

3200

3400

3600

3800

4000

4200

4400

Observed grain yield (kg/ha)

Averaged annual humidity (%)

Equationy = a + b*x

Weight

No Weighting

Residual Sum

of Squares3.49583E6

Pearson's r--

Adj. R-Square-0.00159

ValueStandard Error

BIntercept

3671.4129.02255

Slope1

--

272274

276278

280282

284286

288290

292

2800

3000

3200

3400

3600

3800

4000

4200

4400

Observed grain yield (kg/ha)

Total annual temperature (Celsius degree)Equation

y = a + b*xW

eightNo W

eightingResidual Sum

of Squares

3.50446E6

Pearson's r--

Adj. R-Square-0.00406

ValueStandard Error

BIntercept

3468.13333129.18158

Slope1

--

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0 20

40

60

80

100

120

140

160

0

1000

2000

3000

4000

5000

6000

7000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Yield gap (%)

Maize yield (kg/ha)

Year R

ainfed condition (R-ed)

No w

ater stress condition (NW

S)

Measured condition in reality (observed)

Yield gap between R

-ed condition and Measured condition

Yield gap in comparison betw

een maize yield under R

-ed condition and NW

S condition

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(Anh, 2016)

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3. Climate im

pact on xylem tissue

in woody plants

�

The importance of w

ood as a renewable natural resource

�C

ambial activity and form

ation of wood

�D

endrochronology and variability of tree-ring characteristics �

Plants’ functional adaptations to climate change and cam

bium plasticity

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Xylem functioning and its significance

for plants’ survival

�Transport system

s in plants: xylem and phloem

tissues �

Continuous netw

ork of conduits: root-stem-leaf transport

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Constant environm

ental changes - cavitation and em

bolism occurence

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Linking xylem hydraulic properties to

environment

�Tree-ring anatom

y – definition and significance of this methodological

approach �

Diagram

s and models – sim

plification of hypothesized physical or physiological interrelationships

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�W

ood-anatomical

modifications

can greatly

differ depending

on tree

metabolism

and species specific wood structure, as w

ell as on the timing of

the season when the particular environm

ental event occurs �

Modifications of xylem

tissue, regarding cell size, num

ber and shape �

Seasonal pattern of adaptations

�S

pecies-specific responses to contrasting w

ater supply �

Importance of previous

growing season conditions

�B

imodal patterns of cam

bial activity and cell differentiation

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Photom

icrographs of cross sections from w

ell-w

atered control trees in early (A) and late (C

) sum

mer com

pared with those from

drought-treated trees in early (B

) and late (D) sum

mer.

Black lines show

the size of the different zones of w

ood cell development in control and

drought-treated trees. Num

bered arrows in A

and B give exam

ples of newly form

ed fibers that define the xylem

considered for anatom

ical analysis. Abbreviations: P

h, phloem

; Ca, cam

bium; E

Z, xylem cell

expansion zone; and SW

, secondary cell wall

formation (from

Arend and From

m, 2007).

Deform

ed vessel elements (arrow

s) in the outermost xylem

of drought-treated poplar trees in early (A

) and late (B) sum

mer (from

A

rend and Fromm

, 2007). (B

elow) Tree-ring w

idth chronologies (n = 15) of control and (at least tem

porarily) irrigated oak and pine. Black, trees of the

irrigation or irrigation stop site; grey, trees of the control site; and arrow, the year irrigation stopped (from

Eilm

ann et al., 2009).

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�C

avitation resistance in deciduous vs. evergreen angiosperm

s and conifers �

Influence of non-climatic factors on

xylem attributes – com

petition, soil, individual tree features

Clim

ate change

impacts

on plant’s

functioning w

ill inevitably

increase in

future and

vegetation’s responses

to drought and other environm

ental threats are

the key

factor that

will

determine

plants’ survival rate.

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4. Managing nitrogen for sustainable developm

ent and its role in clim

ate change Tem

perature effects on Nitrogen C

ycle

D

ecomposition of

soil organic matter

faster with high

temperatures

MINERALIZATIO

N (m

icroorganisms

activity) DENITRIFICATIO

N

NITRIFICATION

VOLATILIZATIO

N

warm

soil with urea

broadcast on the surface ideal for am

monia losses

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Precipitation effects on Nitrogen C

ycle

precipitation increase =

plant N uptake from

the soil increase

soil dry = there is less plant transpiration that results in decreased N

uptake

M

INERALIZATIO

N and NITRIFICATIO

N

Conditions of no

oxigen: INCREASED

DENITRIFICATION

Rain

fallW

ithin

days afte

r

app

lication

N vo

latilization

losse

s

0.42

0

0.43

10

0.1 to 0.2

510 to

30

05

30+

Effects o

f rainfall o

n N

volatilizatio

n lo

sses

VOLATILIZATIO

N

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Thermo-rainfall conditions: em

ission N₂O

+ soil moisture

+ temperature

N₂O

: greenhouse gas with high radiative

forcing per unit mass.

Agricultural soils are assessed to produce

2.8 (1.7–4.8) Tg N2O

-N year−1

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The problem of clim

ate change: Nitrogen cycle

For exam

ple hottest and most hum

id conditions could: �

Increase nitrification �

Increase denitrification rates �

Increase nitrogen release by mineralization

�Increase N

2O production

redu

cing p

ow

er on

N₂O em

issions through soil drying and an in

crease in n

itrogen

up

take

Changes in the N

itrogen cycle

Increase global mean

temperature: 1.5°C

to 4°C

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Mitigation strategies for clim

ate change

NU

E im

proved by: -

Rotations w

ith cover crops: improved

yield and crop quality, enhanced erosion protection, reduced runoff and pollutants in runoff, increased soil organic m

atter, incresed biological activity in the soil, reduced soil com

paction. -

Better P

rediction of Crop N

itrogen and W

ater Requirem

ents: needs of the crops m

easured with a

soil test approach or yield goal

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Mitigation strategies for clim

ate change P

recision Nitrogen m

anagement: the right

time and the right place

�M

easuring the concentration of nitrogen in plant sap or plant tissue, or in a laboratory, or directly in the field using a test kit;

�M

easuring the chlorophyll content in the leaves using a simple chlorophyll

meter;

�M

easuring the reflectance of crop foliage through remote sensing

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5. Impact of the environm

ent on uptake of micronutrients

Introduction •

Feeding the world's grow

ing population in the present era of climate change is a

serious challenge.

•C

limate m

odels predict that warm

er temperatures and increases in the frequency

and duration of drought during 21st century w

ill have net negative effect on agricultural productivity. S

cientific publications on the isolated effects of elevated C

O2 level, tem

perature rise and water supply, on crop grow

th and yield synthesis, biom

ass accumulation and crop yield are necessary to predict im

pacts of climate

change on agriculture •

Elem

ental composition in plant tissue is expected to change in future high C

O2

world .

•E

ffects of climate change on soil fertility and the ability of crops to acquire and

utilize soil nutrients is poorly understood, but it is essential for understanding the future of global agriculture.

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Micronutrients in plants

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Drought effect on m

icronutrient acquisition

•C

rop yields

on soils

in developing

countries decrease

exponentially w

ith increasing aridity. S

oil moisture deficit directly im

pacts crop productivity and also reduces yields through its influence on the availability and transport of soil m

icronutrients. •

Drought increases vulnerability to nutrient losses from

root zone to erosion. B

ecause nutrients are carried to the roots by water, soil m

oisture deficit decreases nutrient diffusion over short distances.

•R

eduction of root growth and im

pairment of root function under drought thus

reduces micronutrient acquisition capacity of root system

. •

In wet soils. Fe

2+/Fe3+ ratio is higher, w

hich results in greater Fe availability for plants. U

nder drought condition, the greater presence of O2 in the soil induces a

decrease in the Fe2+/Fe

3+ ratio, leading to a decrease in available Fe for plant absorption, since Fe

2+ is more soluble then Fe

3+ . •

The conversion of Mn to its reduced and m

ore soluble forms is increased in

moist soil conditions

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Drought effects on m

icronutrient acquisition •

Mahonachi et al. (2006) found an increase of Cl - concentration in leaves and

roots of papaya after 34 days of water stress. H

ence, together with organic

solutes these ions contribute to osmotic adjustm

ent in plants and therefore, under conditions of low

supply, symptom

s are visible mainly in aerial m

eristems, young

leaves and reproductive organs. •

Cu critical free concentration in the media ranges from

10-14 M to 10-16 M

. B

elow this range C

u deficiency occurs.

•A

ccording to Reddy (2006) B

deficiency is mainly seen in soils w

ith high pH and

under drought conditions. •

The lower diffusion of Zn in dry soil restricts uptake of Zn and m

ay exacerbate Zn deficiency.

•H

igher Ni mobility w

as also reported in the soils with low

er humus content, lighter

granulometric com

position and higher moisture content.

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•

Surface erosion during intense precipitation events is a significant source of soil

nutrients loss in developing countries. •

Agricultural areas w

ith poorly drained soils or that experience frequent and/or intense rainfall events can have w

aterlogged soils that become hypoxic.

•The change in soil redox status under low

oxygen can lead to elemental toxicities

of Mn, Fe, B, N

i, which reduces crop yields and the production of phytotoxic

organic solutes that impair root grow

th and function. •

Hypoxia can also result in nutrient deficiency since the active transport of ions

into root cells is driven by ATP synthetized through the oxygen dependent m

itochondrial electron transport chain.

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Effect of high temperature and elevated C

O2 level on m

icronutrient aquisition

• If under dry conditions higher temperatures result in extrem

e vapor pressure deficits that trigger stom

atal closure (reducing the water diffusion pathw

ay in leaves), then nutrient acquisition driven by m

ass flow w

ill decrease. • Tem

perature driven soil moisture deficit slow

s nutrient acquisition as the diffusion pathw

ay to roots becomes longer as ions travel around expanding soil air pockets.

• Projections to the end of this century suggest that atm

ospheric CO

2 will top 700 ppm

or m

ore, whereas global tem

perature will increase by 1.8–4.0 °C

, depending on the greenhouse em

ission scenario. • C

rops sense

and respond

directly to

rising C

O2

through photosynthesis

and stom

atal conductance.

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•

The net effects of climate change w

ill be negative for agricultural production. •

Drought induced by higher tem

peratures and altered rainfall distribution would

reduce nutrient acquisition. •

More intense precipitation events w

ould reduce crop nutrition by causing short-term

root hypoxia, and in the long term by accelerating soil erosion.

•Increased tem

perature and elevated CO

2 level will reduce soil fertility by

increasing soil organic matter decom

position, and may have profound effects on

crop nutrition by altering plant phenology.

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Ge

ne

ral con

clusio

n

•In previous sections, clim

ate change impact on different aspects of crop production

was

described. The

question w

hich arises

is how

can

crop productivity

be increased w

hile ensuring the sustainability of agriculture and the environment for

future generations? •

Changes in environm

ental conditions may substantially alter N

balance and cycling, w

hich links geosphere, biosphere and atmosphere, thus producing considerable

challenges in terms of nitrogen m

anagement.

•

Additional studies that investigate plant hydraulics over space and tim

e are greatly needed to assess the vulnerability of crops to clim

ate change and possibilities to im

prove plant resilience.

•The results suggest that the indices w

ill become even m

ore valuable tool for researches

to gain

better understanding

of global

climate

change effect

on agriculture.

•G

iven the potential adverse impacts on agriculture that could bring about clim

ate change, it is w

orthwhile to conduct m

ore in-depth studies and analyses to gauge the extent of problem

s that agriculture may face in the future.