the effects of conservation agriculture on crop performance, soil quality and potential c emission...
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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
on
ven
tio
na
l ag
ric
ult
ure
Co
ns
erv
ati
on
ag
ric
ult
ure
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
(m
m)
Precipitation (mm) pET (mm) pET/2 (mm)
LGP
Soil Classification
Rastra
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 PB
K R P K R K P
MM MM MM MM
MW MW MW MW MW MW MW
WM WM WM WM WM WM WM
WW 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 tillage
Maize 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 4.9
Rotation - 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
Top
Soi
l Res
ista
nce
ZT, R
ZT, K
CT, R
CT, K
Loadings
1
3
7
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, R
ZT, K
CT, R
CT, K
Loadings1
3
7
132
4
8
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 Nitrogen
Treatment ————————————— (mg kg-1) ——————————
Tillage b
PB K 18.56 A 1.97 A 19.35 A 2.10 A 13.82 A 1.70 A
CB I 8.56 B 1.05 B 15.25 B 1.75 B 11.87 A 1.49 A
Residue management c
PB K 18.56 A 1.87 A 19.35 A 2.09 A 13.82 A 1.70 A
PB P 9.83 B 1.20 B 17.11 A 1.91 A 14.29 A 1.66 A
PB 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 6.40
LSD (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
