The effects of conservation agriculture on crop The effects of conservation agriculture on crop performance, soil quality and potential c emission performance, soil quality and potential c emission

reduction and c sequestration in contrasting reduction and c sequestration in contrasting environments in Mexicoenvironments in Mexico

Bram Govaerts, Ken Sayre, Nele Verhulst, Luc Dendooven

Agustin Limon-Ortega Leonardo Patiño-Zúñiga

Conservation Agriculture

Comprises three basic components Surface crop residue retention Minimal soil movement Crop rotation

Intensity of soil disturbance

Crop rotation C

onve

ntio

nal a

gric

ultu

re

Con

serv

atio

n ag

ricul

ture

Conventional MinimumTillage

Direct seeding

Sustainable agriculture

Adapted from Pereira

Surface crop retention

Conservation Agriculture is a complex technology: it involves a

complete change in the agricultural system.

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

Climate

0

50

100

150

200

1 2 3 4 5 6 7 8 9 10 11 12Month

Prec

ipita

tion

and

pET

(mm

)

Precipitation (mm) pET (mm) pET/2 (mm)

LGP

Soil ClassificationRastra

Arado

Ap

Ap0’

A

2Bw

2C

Cumulic Phaeozem

Fine, mixed, thermic Cumulic Haplustoll

Characteristics Non-equatorial semi-arid

subtropical highlands (2240 masl)

Periodical drought

Periodical water excess

Wind and water erosion

Rain fed agriculture

Grain yield < 3 ton ha-1

DROUGHT

EROSION

Experimental Fields

Treatments

K = Keep residue on the field; R = Remove the residue ; P = Partial residue retention

W = Wheat; M = Maize; B= Beans

ZT CT PBK R P K R K P

MM MM MM MMMW MW MW MW MW MW MWWM WM WM WM WM WM WMWW WW WW WW

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

27.33oN; 109.09oW 38 m asl T(max) 26.7oC; T(min) 8.7oC Wheat growing season: November-May Maize – Sorghum: June - October

Características del Valle del Yaqui

Soil – Station Obregon, Sonora, México

Suelo – Vertisol

Calcareous Vertisols (mixed montmorillonitic typic Calciorthid)

Low organic matter: 0.95 % (0-30 cm)

Slightly alkaline: PH (CaCl2) = 7.7

E.C. 0.8-1.9 dS m-1 (30-90 cm: 4.15 dS m-1)

% Clay Lime Sand

0-30 43 24 33

30-60 48 25 27

Results: Yield

Towards a high and stable yielding system ?

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

Govaerts et al., 2005

Govaerts et al., 2005

Zero vs. ConventionalZT

ZT

CT

CT

Govaerts et al., 2005

Yield results 1997-2005

Govaerts et al., 2005

Zero-tillage Conventional tillageMaize Wheat Maize Wheat

Monoculture + residue 4.3 5.3 3.5 4.9

Monoculture - residue 2.2 4.4 3.4 4.3

Rotation + residue 5.1 5.4 4.2 4.9Rotation - residue 4.0 3.4 3.8 4.4

Yield Stability

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1990 1995 2000 2005

MM, CT, K

MM, CT, R

WM, CT, K

WM, CT, R

Govaerts et al., 2005ZT = zero tillage, CT = conventional tillage

K = keep residue; R = remove residue

W = wheat; M = maize

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

Sayre et al., 2006

6,2256,356

3,978

7,190

4,985

6,950

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000

Rendimiento de grano(kg/ha)

Costos de producción(MXN)

Ingresos (despues costos)(MXN/ha)

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000M

exican pesosLSD for Rendimiento (0.05) = 563 kg/ha

Camas convencionales

Camas permanentes

Ren

dim

ient

ode

gra

no(k

g/ha

at 1

2% H

2O)

6,2256,356

3,978

7,190

4,985

6,950

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000

Rendimiento de grano(kg/ha)

Costos de producción(MXN)

Ingresos (despues costos)(MXN/ha)

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000M

exican pesosLSD for Rendimiento (0.05) = 563 kg/ha

Camas convencionales

Camas permanentes

Ren

dim

ient

ode

gra

no(k

g/ha

at 1

2% H

2O)

Soil quality, not just a word but a conceptual framework

Soil quality Variety of definitions

Doran and Parkin (1994)“it is the capacity of a soil to be functional, within the limits imposed by the ecosystem and land use, to preserve the biological productivity and environmental quality, and promote plant, animal and human health”

Larson and Pierce (1994) “fitness for use”

Selection Soil Parameters Limiting factor set: comparison of optimal

conditions for land use and field conditionsIdeal conditions for land use versus real conditions

Measuring possible critical indicators linked with the limiting factors

Multivariate analysis => most explicative indicators = minimum dataset

(M)ANOVA

Chemical parameters 0-5 % C Physical parameters Time-to-pond without plants % N Time-to-pond with plantsK % Macro aggregatesMn Permanent Wilting Point Zn Cone Penetration

Chemical parameters 5-20 % C Mean Weight Diameter Na Probe DepthMn

Indicators influenced by• Residue• Tillage

Biological parameters are weak!

Selected ParametersGroup Chemical 0-5 Chemical 5-20 Physical Biological

Indicator CEC CEC Small Ring Infiltration BTWC MBB C% C % C Small Ring Infiltration IC MBB N% N % N Time-to-pond without plantspH pH Time-to-pond with plantsP P % Macro aggregatesCa Ca % Meso aggregatesMg Mg % Micro aggregatesK K Field capacity (0-5)Na Na Field capacity (5-20)Fe Fe Permanent Wilting Point (0-5)Mn Mn Permanent Wilting Point (5-20)Zn Zn Bulk densityCu Cu Mean weight diameterEc Ec Cone penetrationNH4+ NH4+ Probe depthNO3- NO3- PEN-7

PEN-17PEN-27

PCA Soil physical properties

Govaerts et al., 2006

-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

PC Soil Structure

PC T

op S

oil R

esist

ance

ZT, RZT, KCT, RCT, KLoadings

1

37

132

4

8

14

5

119

12

106

15

16

CP%MA

PR

PWP

MWDTTPWP

TTPP

Govaerts et al., 2006

PCA Soil chemical properties

-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

PC 0-5 Nutrient Status

PC 0

-5 M

n

ZT, RZT, KCT, RCT, KLoadings

1

3

7

132

48

14

511

9

12

106 1516

Mn

Zn%C

K

%N

Aggregate stability

Coarse POM-C + sand (CPOM mM)

(>250 μm)

Silt + Clay (<53μm)

Microaggregates (m) (53-250 μm)

Macroaggregates (M)

(>250 μm)

Total Soil

Micros within Macros (mM)

(53-250 μm)

Silt and clay (s+c mM)

(>53 μm)

Inter-mM-POM-C

(53-250 μm)

Intra-mM-POM-C

(53-250 μm)

Microaggregate isolator

Density floatation + dispersion

Wet sieving

Aa

ABBb

Aa

AB

Bb

0

5

10

15

20

25

30

35

40

45

50

CTB + Res PB + Res PB + Part PB - Res

Larga Macro-aggregates Small Macro-Aggregates

Lichter et al., 2008

—————————————————————————————————————————

cPOM a Microaggregates within

macroaggregates

Silt and cay fraction of

macroaggregates——————— ——————— ————————

Carbon Nitrogen Carbon Nitrogen Carbon NitrogenTreatment ————————————— (mg kg-1) ——————————Tillage b

PB K 18.56 A 1.97 A 19.35 A 2.10 A 13.82 A 1.70 ACB I 8.56 B 1.05 B 15.25 B 1.75 B 11.87 A 1.49 AResidue management c

PB K 18.56 A 1.87 A 19.35 A 2.09 A 13.82 A 1.70 APB P 9.83 B 1.20 B 17.11 A 1.91 A 14.29 A 1.66 APB R 8.61 B 1.29 B 16.05 A 1.86 A 14.19 A 1.72 A—————————————————————————————————————————

Lichter et al., 2008

CO2 flux

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1

CO

2 flu

x (g

CO

2 m

-² h-

¹)

MW, CT, K

MW, ZT, K

WM, CT, K

WM, ZT, K

Residues Management

Tillage

Patiño-Zúñiga et al., 2008

Cd. Obregón39 m

Agua Fría60 m

Tlaltizapán940 m

MexicoCity

El Batán*2249 m

Toluca2640 m

Mexicali22 m

CIMMYT in Mexico

Tillage/Residue Management

%OrganicMatter

NaPpm

Aggregate Distribution MWD

AggregateStability MWD

SMB C

mg kgsoil-1

SMB N

mg kgsoil-1

Conventional Till Beds Incorporated Residue

1.23 564 1.32 1.262 464 4.88

Permanent Beds Burn Residue

1.32 600 0.97 1.12 465 4.46

Permanent Beds Partial Removal Residue

1.31 474 1.05 1.41 588 6.92

Permanent Beds Retain Residue

1.43 448 1.24 1.96 600 9.06

Mean 1.32 513 1.15 1.434 552 6.40LSD (P=0.05) 0.15 53 0.22 0.33 133 1.60

Implementation of conservation agriculture through a network

of hubs

The hub concept benchmark sites for research on the impacts of

CA

focal point for regional (agro-ecological) capacity-building and scaling out of research and innovation systems

regional CA networks are established to facilitate and foment research and extension of CA innovation systems and technologies

example of the functionality of CA systems

structure to work together with partners including farmers to test various best-bet technology options with farmers

to integrate these options to improve farm level economics and family well-being

to provide a demonstration platform to extend these technologies to surrounding farmers

to provide a training/demonstration platform to bring together all actors from other areas with similar production systems and conditions

to provide a platform to do relevant research

Strategic research feeding into the international network of hubs

Literature review Govaerts et al., submitted

West and Post (2002), Jarecki and Lal (2003), VandenBygaart et al. (2003), Blanco-Canqui and Lal (2008) + Literature search (Web of Science)

Only >5y and minimum 30cm

Very little research in Africa, Central- Latin- America, Asia

Literature review Conventional till Zero tillage

8/62 cases C stock decreased

21/62 cases C stock not significant different

33/62 case C stock increased

Increased rotation 22/55 cases C stock decreased

5/55 cases C stock not significant different

28/55 cases C stock increased

Conclusions Not always increase in C stock

Why? Not clear

Underlying processes seem not fully understood

Need for an international network of hubs linked to strategic research sites

Even if CA does not lead always to C stock increase it is still the best practice to promote

Thanks

b.govaerts@cgiar.org