Integration of Canavalia brasiliensis - sfiar.ch · Integration of Canavalia brasiliensis into the crop-livestock system of the Nicaraguan hillsides: environmental adaptation and

Integration of Canavalia brasiliensis

into the crop-livestock system of the Nicaraguan hillsides:

environmental adaptation and nitrogen dynamics

Sabine Douxchamps

13 November 2012

background

Facts:

80 % of population with less than $2/day

27% of population undernourished

Hillsides: 80% smallholders (crop-livestock)

Agricultural

productivity decrease

Continuous cropping

Use of marginal lands Income decrease

Food insecurity

Nitrogen (N)

depletion

background

1st rainy season 2nd rainy season dry season

Maize Bean

Livestock

background


Maize Bean

Livestock

Introducing a cover crop legume:

▪ N input through symbiotic N2 fixation

▪ as green manure benefit to the next crop

build up organic matter stocks

cover the soil against erosion

▪ as forage increase amount and quality of dry season feed

background


Maize Bean

Canavalia brasiliensis

Livestock

Canavalia brasiliensis

▪ produce a lot of biomass

▪ drought tolerant

▪ selected by farmers

background

when introducing a legume into a smallholder hillside system…

where to plant it?

what limits its agricultural performance?

what is its net N input to the system?

how to use it?

how do farmers want to manage it?

what is the benefit to the next crop?

how much remains in the soil?

background


where to plant it?


→ biomass study - landscape scale


how to use it?


→ N budgets study - plot scale



→ 15N study - microplot scale

10 000 m2

100 m2

1 m2

background


synthesis N dynamics biomass

where to plant it?


→ biomass study - landscape scale


how to use it?


→ N budgets study - plot scale



→ 15N study - microplot scale

10 000 m2

100 m2

1 m2

impact

background

aim determine soil and topographic factors that

influence canavalia biomass production

material and methods ▪ soil chemical and physical properties

▪ soil profiles and rooting patterns

▪ topography

0

1-1000

1000-2000

2000-3000

3000-4000

4000-5000

5000-6000

bean

canavalia biomass 07 (kg/ha)

AR

PT

MP

FC

GR

LP

impact biomass N dynamics synthesis

Douxchamps et al. 2012, J. Agr. Sci 150

background

5000

4000

3000

2000

1000

Bio

ma

ss (

kg

ha

-1)

AR1 AR2 FC1 FC2 GR1 GR2 LP MP1 MP2 PT

1000

3000

5000

Profile groups

Cana

valia

biom

ass (

kg/ha

)


1000

3000

5000

Profile groups

Cana

valia

biom

ass (

kg/ha

)


1000

3000

5000

Profile groups

Cana

valia

biom

ass (

kg/ha

)


1000

3000

5000

Profile groups

Canav

alia bio

mass

(kg/ha

)

0

20

40

60

80

100

120

140

Ap

B

C

Cm

C

Cb

CBm

0

20

40

60

80

100

120

140

Ap

B

C

Cm

C

Cb

CBm

Ap

B

C

Cm

C

Cb

CBm

0

20

40

B

Cm

0

20

40

B

Cm

0

20

40

60

80

100

120

140

A

B/C

C

0

20

40

60

80

100

120

140

A

B/C

C

A

B/C

C

river

OA

C/Bh

Bk

0

20

40

60

80

OA

C/Bh

Bk

0

20

40

60

80

canavalia biomass production was significantly affected

by soil depth, C and N, slope position, clay and stones


Douxchamps et al. 2012, J. Agr. Sci 150

background

aim ▪ assess net N input from canavalia to the system

▪ describe how its use as forage or green manure affects soil N stocks

material and methods

4 farms, 5 treatments (M/B and M/C with grazing simulation), 2 years


Douxchamps et al. 2010, Nutr. Cycl. Agroecosyst. 88

NPK

UREA

N balance [kg N ha-1] = (N fert + N seed + N fix) – (N export)

15N natural abundance method

background

results

2007

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

2008

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

M/B M/C0 M/C50 M/C75 M/C100

2007

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

2008

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

M/B M/C0 M/C50 M/C75 M/C100



[kg N ha-1]

▪ N2 fixation: bean ~ 3

canavalia ~ 20

▪ seed: ~ 3

▪ mineral fertilizer: 38 - 68

▪ export: maize: 16 - 67

bean: 0 - 11

canavalia: 0 - 87

background

results

2007

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

2008

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

M/B M/C0 M/C50 M/C75 M/C100

▪ canavalia as green manure: net N input due to symbiotic

N2 fixation

▪ canavalia as forage: depletes soil N… return of animal

manure?

▪ mineral fertilizers necessary for positive N balance

2007

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

2008

-80

-60

-40

-20

0

20

40

60

80

FC GR LP PT

kg

N h

a-1

M/B M/C0 M/C50 M/C75 M/C100



[kg N ha-1]

▪ N2 fixation: bean ~ 3

canavalia ~ 20

▪ seed: ~ 3

▪ mineral fertilizer: 38 - 68

▪ export: maize: 16 - 67

bean: 0 - 11

canavalia: 0 - 87

background impact biomass N dynamics synthesis

aim determine the fertilizer value of canavalia residues and animal manure for maize


15N direct and indirect labelling techniques: maize growing in microplots amended

with mineral fertilizer, canavalia residues, or cow manure.

Douxchamps et al. 2011, Plant Soil 341


aim determine the fertilizer value of canavalia residues and animal manure for maize


15N direct and indirect labelling techniques: maize growing in microplots amended

with mineral fertilizer, canavalia residues, or cow manure.

results

0

10

20

30

40

50

60

70

80

90

100

Mineral

fertilizer

Canavalia

residues

Check

manure

rec

ove

ry (

%)

Maize N OM + clay Nmin Nmic

▪ canavalia residues are a valuable source of N for maize

▪ canavalia built up soil organic matter with time

Douxchamps et al. 2011, Plant Soil 341


Canavalia has the potential to improve the crop-livestock system:

can produce high amounts of biomass and tolerate drought

fixes significant amounts of N

▪ as green manure: - increases the N balance and benefit to the subsequent crop

- decreases net annual income by 12% on the short term

▪ as forage: - increases milk yields during the dry season (1l/day.cow)

- increases net annual income by 8%

- risk of N depletion


Canavalia has the potential to improve the crop-livestock system:

can produce high amounts of biomass and tolerate drought

fixes significant amounts of N

▪ as green manure: - increases the N balance and benefit to the subsequent crop

- decreases net annual income by 12% on the short term

▪ as forage: - increases milk yields during the dry season (1l/day.cow)

- increases net annual income by 8%

- risk of N depletion

Farmers perceive a positive effect of

canavalia to the system and want to use it as forage


▪ the best way for mitigating soil nutrient depletion and increase livestock productivity

would be to

1. use canavalia first as forage

2. improve animal manure management

3. use canavalia regrowth as green manure

▪ canavalia should be seen as one element of a

management strategy for a progressive restoration of

degraded soils and optimal nutrient flows

- other soil conservation practices (life barriers or

stone rows in slopes)

- complex rotations with various legumes,

diversification

background impact

Adoption by smallholders was facilitated through

▪ development and distribution of booklets for farmers and extensionists

▪ seed production

▪ seed release by local authorities

biomass N dynamics synthesis

→ farmers want to be involved in seed production

→ government and other local institutions start to integrate it

in their programs

acknowledgements

Prof. Dr. Emmanuel Frossard (ETH)

Dr. Astrid Oberson (ETH)

Dr. Idupulapati Rao (CIAT Colombia)

Dr. Axel Schmidt (CIAT Nicaragua)

Dr. Rein van der Hoek (CIAT Nicaragua)

Martin Mena (INTA)

the farmers of Santa Teresa

the North-South Center of ETH Zurich

acknowledgements

Prof. Dr. Emmanuel Frossard (ETH)

Dr. Astrid Oberson (ETH)

Dr. Idupulapati Rao (CIAT Colombia)

Dr. Axel Schmidt (CIAT Nicaragua)

Dr. Rein van der Hoek (CIAT Nicaragua)

Martin Mena (INTA)

the farmers of Santa Teresa

the North-South Center of ETH Zurich

thank you

for your attention

Documents

Integration of Canavalia brasiliensis - sfiar.ch · Integration of Canavalia brasiliensis into the crop-livestock system of the Nicaraguan hillsides: environmental adaptation and