Title: Sustainable low-input cereal production: required varietal characteristics and crop diversity
1Sustainable low-input cereal productionrequired
varietal characteristics and crop diversity
- Working Group 4 plant-plant interactions
2About SUSVAR.
- System characteristics
- Cereal production
- Low-input conditions
- Aims
- Increased stability (yield and quality)
- Increased resource use efficiency
- Main means
- Better use of crop genetic diversity
3Better use of crop genetic diversity (1)
- Selection of suitable genotypes
- Better use of available gene-pool for low-input
systems - Varieties that are well suited to low-input
conditions in general - Varieties that are well suited to specific
conditions (environmental conditions by
definition more variable than under high-input
conditions)
4Better use of crop genetic diversity (2)
- Use of mixtures
- Utilize more genotypes simultaneously
- Heterogeneity contributes to stability (risk
avoidance) - Generation of added value
- Facilitation
- Competition
5Crop - environment mutual interaction
environment
Crop A
6Facilitation positive effect
environment
crop
Crop A
Crop B
7Facilitative production principle insects
8Competition negative influence
environment
-
crop
Crop A
Crop B
9Competitive relations are important
10Competition also the basis for over-yielding
- Competitive production principle
- intra-specific competition gt inter-specific
competition - Niche-differentiation or complementarity
- ? better exploitation of available resources
11Facilitative production principle weeds
- Facilitation
- (the creation of a weed free environment)
- is through
- Competition
- (suppression of weeds by other crop)
- Challenge avoid other crop from developing into
a weed.
12Facilitative production principle weeds
13Working group plant-plant interaction
- Crop weed interaction
- Weed suppression
- Which traits
- General or environment specific
- Easy screening procedures
14In case of mixtures
- Crop crop interaction
- Yield stability
- Difference in stress-tolerance
- Productivity
- Niche differentiation
- Intra-specific competition gt inter-specific
competition
15Weed suppression of mixtures
- Crop crop weed interaction
- How to maximize weed suppression?
- Combine most competitive cultivars
- Maximize complementarity
- Complementarity in resource use and acquisition
- Complementarity in weed suppression mechanism
16Currently many different questions .
- What do we want to obtain with mixtures?
- (stability, productivity, weed suppression,
others) - How can added value of mixtures be obtained?
- (what is the best strategy)
- How to select individual varieties for their
performance in mixtures?
17Time to decide on where to go
18(No Transcript)
19Organisation of activities and reciprocal
benefits
WG 3 Plant Soil Interactions
WG 4 Plant Plant Interactions
WG 1 Genetics Breeding
WG 6 Variety testing certification
WG 2 Biostatistics
WG 5 Plant Disease Complex
20Facilitative production principle diseases
21Plant-plant interaction
- Main issues
- Productivity
- Stability
- Weed suppression
22Learning-objectives
- To familiarise with options for evaluating
- productivity
- competitive relations
- within intercropping systems
- To be able to value the various methodologies
- To learn the relationship between some indices of
relative competitive ability
23Multiple cropping
- Growing two or more crops on the same field in a
year - - sequential cropping
-
- - relay intercropping
-
- - full intercropping
-
time
24Reasons for intercropping
- Better use of available resources
- (land, labour, light, water, nutrients)
- Reduction in pest pressure associated damage
- (diseases, insects, weeds)
- Socio-economic
- (greater stability, risk avoidance, food/cash
crops) - Sustainability
- (erosion, soil fertility)
25Facilitative production principle diseases
Causal organism Magnaporthe grisea two
phases vegetative stage Leaf blast reproductive
phase Neck or panicle blast
26Intercropping as weed management component
Leek monoculture
weed-free period
manual weeding
mechanical weeding
Weeds
Leek-Celery Intercrop
weed-free period
mechanical weeding
Weeds
Transplanting
Harvest
27Competition the basis for over-yielding?
- Niche-differentiation
- ? better exploitation of available resources
- separation in time (relay)
- separation in space (rooting depth)
- different resource capture abilities
- different growth requirements
-
28Key to evaluation of intercrop productivity
- Quantification of competitive relations
- Example
- Two-species mixture (sp 1 - sp 2)
- How many competition coefficients?
-
-
29Key to evaluation of intercrop productivity
- Quantification of competitive relations
- Example
- Two-species mixture (sp 1 - sp 2)
- How many competition coefficients?
- 2 intraspecific competition coefficients b11,
b22 - 2 interspecific competition coefficients b12,
b21
30Intraspecific competition
YN/(b0b1N) ? WY/N1/(b0b1N) ? 1/Wb0b1N
31Measure of intraspecific competition
- 1/W1b10b11N1
- b10 plant/g
- b11 m2/g
- b11/b10 m2/plant
- crowding coefficient (de Wit)
- ecological neighbourhood area (Antonovics Levin)
32Intercropping intra and interspecific
- 1/W1b10b11N1 b12N2
- b11/b12 relative competitive ability
- What does this value learn us?
33Intercrop productivity
- 1/W1b10b11N1 b12N2
- and
- 1/W2b20b22N2 b21N1
- b11/b12 and b22/b21
- Niche differentiation index (NDI)
- b11/b12 b22/b21 (b11b22)/(b12b21)
- NDI 1,lt1,gt1
34How can we determine these indices?
35Evaluation in practice
- Experiment with three treatments
- Monoculture of species 1? Y1,mono
- Monoculture of species 2 ?Y2,mono
- Mixture of species 1 and 2 ?Y1,mix, Y2,mix
- Calculation of Relative Yield
- RY1 Y1,mix/Y1,mono
- RY2 Y2,mix/Y2,mono
- Land Equivalent Ratio (LER)
- LER RY1 RY2
- relative land area under sole crops required to
produce the yields achieved in intercropping
36Two basic designs
- Additive design
- 0 0 0 0 x x x x 0 x
0 x 0 x 0 x - 0 0 0 0 x x x x 0 x
0 x 0 x 0 x - 0 0 0 0 x x x x 0 x
0 x 0 x 0 x - 0 0 0 0 x x x x 0 x
0 x 0 x 0 x - 0 0 0 0 x x x x 0 x
0 x 0 x 0 x - species 1 species 2 mixture
37Two basic designs
- Replacement design
- 0 0 0 0 x x x x 0
x 0 x - 0 0 0 0 x x x x 0
x 0 x - 0 0 0 0 x x x x 0
x 0 x - 0 0 0 0 x x x x 0
x 0 x - 0 0 0 0 x x x x 0
x 0 x - species 1 species 2 mixture
38Replacement design
- Overall density constant
- Results represented in a replacement diagram
- LER generally replaced by Relative Yield Total
(RYT) - Relative crowding coefficient (k) to express
competitive relations - k12(1-z1)/(w11/w12-z1)
- z1fraction species 1
39Replacement design
- k ? intrasp/intersp comp.
- Similar to b11/b12?
- kk
- related to intercrop productivity
- 1, gt1, lt1
- Similar to NDI?
40Excercises
- Complete calculations on two intercrops
- grown at two different densities
- in replacement and additive design
- Focus on
- What is the difference between outcomes from a
replacement and an additive design? - What is the difference between relative crowding
coefficient (k) and the ratio of competition
coefficients (e.g. b11/b12)?