Soil information demand for crop simulation Introducing AquaCrop

Pasquale STEDUTO Deputy Director

Land & Water Division FAO, Rome

Towards Global Soil Information 20-23 March, 2012 - FAO Headquarters

Rome, Italy

Atmosphere

Soil

Crop

AquaCrop Conceptual Framework

Man

agem

ent

CLIMATE Rain

AquaCrop Conceptual Framework | Atmosphere

RS, T, RH, u

ETo T (oC) CO2

T (oC) Es Ta ETo

Phenology Canopy Cover Leaf expansion gs

Senescence Biomass

WP

Yield HI

Rooting depth

AquaCrop Conceptual Framework | Crop

CO2

Canopy Cover (CC)

Vertical projection of canopy foliage

Shaded area over ground area

(%)

CGC

CCx

start of canopy senescence

time to harvest

cano

py c

over

timetime to full canopy

CDC

CCo

• CC follows the exponential growth during the first half of the full development (Eq. 1) and an exponential decay during the second half of the full development (Eq. 2)

tCGCoeCCCC ⋅= (1) tCGC

oxx e)CCCC(CCCC ⋅−⋅−−= (2)

WP Water Productivity

(g m-2 mm-1) ∑

=CT

BiomassWP(g m-2)

)2000(COO

C

*

2ETT

BiomassWP

=

∑

Σ ETc (mm x 1000)0.0 0.3 0.6 0.9

Bio

mas

s (k

g m

-2)

0

1

2

3

SorghumSunflowerChickpeaWheat

∑ CT Σ(ETc/ETo)0 40 80 120 160

Bio

mas

s (k

g m

-2)

0

1

2

3

SorghumSunflowerChickpeaWheat

∑ )ET/T( OC

multiplier x HIo (reference)

upward or downward adjustment

Harvest Index

Y = HIadj x B

adjusted for: water and/or temperature stress

Y HI (biomass) B (yield)

Yield

root

ing

dept

hsowing transplanting

emergencetransplanting

timeZini

Zn

Zx

averageexpansion rate

to/2

to

tx

Soil water (& salt) balance Infiltration

Uptake Redistribution

Runoff

Rain

Ks

Es Ta

AquaCrop Conceptual Framework | Soil

deep percolation

capillary rise

Leaf expansion gs

Senescence

HI

Texture 1

Texture 2

Texture …

Ksat

FC

PWP

Irrig.

Runoff

runoff

irrigationrainfall

capillaryrise

deeppercolation

stor

ed s

oil w

ater

(mm

)

Wr

evaporation

0.0

transpiration

Field Capacity (FC)

Permanent Wilting Point (PWP)

TAW

Total Available soil Water

soil water balance

Ks

(1) leaf expansion

HI (4)

(2) gs

(3) senescence

Ks for leaf expansion, maize

Ks for stomata, maize

Ks for senescence, maize

+ aeration & T stresses

Field Management

Water Management

• Fertility level (non-limiting; moderate; poor)

• Field-surface practices (mulching; soil bunds)

Rainfed

• User defined schedule (timing and depth)

• Model-generated schedule (fixed interval; fixed depth; % of RAW) • Irrigation method (drip; sprinkler; surface » basin; border; furrow)

Irrigation

AquaCrop Conceptual Framework | Management

Atmosphere

Soil

Crop

Man

agem

ent

Summing up

CLIMATE

T (oC) Es Ta

Phenology Canopy Cover Leaf expansion gs

Senescence Biomass

WP

Yield HI

CO2

Soil water (& salt) balance Infiltration

Uptake Redistribution

deep percolation

capillary rise

Rooting depth

ETo

Rain

Runoff

Soil information demand • Texture of different layers along the profile

• Derivation of FC, PWP & Ksat from pedo- transfer functions or measurements

• Status of soil fertility (CEC, OM, others)

• Presence of impermeable, or other constraining, layers

• Information on depth and underlying geology, for drainage and deep percolation inferences

•Main scientific publications 2009

Crops dealt by AquaCrop

• Wheat • Maize • Rice • Sugarbeet • Soybean • Cotton • Potato • Quinoa • Sunflower • Bambara groundnut

• Sugarcane • Tomato • Teff • Barley • Sorghum

• Forage crops (Alfalfa)

• Millet • Chickpea • Cassava • Amaranths • Sweet potato

Already calibrated

For the near future

NO TREE CROPS

Thank You

www.fao.org/nr/water