http://www.fao.org/about/meetings/agroecology-symposium-china/en/ Presentation of Paul Mapfumo, from University of Zimbabwe and Soil Fertility Consortium for Southern Africa, on soil management to reduce fertilizer use in Africa. The presentation was prepared and delivered in occasion of the International Symposium on Agroecology in China, held in Kunming, China on 29-31 August 2016.

1. Creating Virtuous Cycles in Soil
Management to Reduce Fertilizer
Use in Africa
Prof. dr. Paul Mapfumo
Department of Soil Science & Agricultural Engineering
UNIVERSITY OF ZIMBABWE
&
Soil Fertility Consortium for Southern Africa (SOFECSA)
University of Zimbabwe

2. University of Zimbabwe
“Our focus is on transforming African agriculture and food
systems through management of soil ecological processes:
as a fundamental precondition for the continent’s
sustainable development”
 Food and nutrition insecurity is at the core of Africa’s
development problem
 80% for food production attributable to smallholders
 Huge yield gaps continue to exist due to poor soil fertility
 Large scale-scale commercial entities not necessarily benefiting
the vulnerable farming families (e.g. have no access to output
markets)
 Potential benefits local ecological diversity ignored in favour of
external input agriculture based on monoculture : even against
all odds
Introduction

3. University of Zimbabwe
Back then... We were poor but not
hungry.....
Now we are ‘Poor and Hungry’?
Common Quote from farmers in
Southern Africa
lamenting the loss of agroecology?..

4. University of Zimbabwe
Less obvious links between soil
biogeochemical processes and poverty traps:
lamenting the loss of agroecology
 Nutrient mining and ‘Maize poverty traps’ in E & SAfrica
 Shrinking arable/grazing lands: Soil erosion & land
degradation
 Extensification and nutrient transfers in crop-livestock
systems (e.g. semi-arid agro-ecologies)
 Soil organic carbon depletion: degradation of wetlands
(loss of ‘food supply buffers’)
 Breaking of tight nutrient cycles in fragile environments:
e.g. declining soil productivity in miombo-ecozones)

5. Mazhanje (Kg fresh weight) per year
0 100 200 300 400
Resource Endowed
Intermediate
Resource Constrained
Consumed (SED =6.81)
Sold (SED=13.95)
Vulnerable households more dependent
on local ecological diversity
Chagumaira et al 2015
Fig. 7. Contribution of nontimber forest products to energy
consumption in times of normal and poor rainfall, shown in
percentage of the total intake per person per year (MJ).
Woittiez et al., 2013

6. University of Zimbabwe
1. Harnessing local ecological diversity:
The Indigenous legume fallow (Indifallow)
Concept
 Naturally growing indigenous
legumes collected by farmers
 Local technique (by smell)
developed to enable farmers to
distinguish between legumes &
non-leguminous plants in the
field (Mapfumo et al 2005)
 Mixed stands of legumes sown
on farmers’ abandoned fields &
left for 1 or 2 seasons
 Dominant and competitive
species defined the biomass yield
Remarkable$diversity$even$in$dry$areas$
Crotalaria
pisicarpa
42%
Indigofera
flavicans
1%
Macrotyloma
daltonii
8%
Indigofera
astragalina
6%
Stylosanthes
fruticosa
1%
Rothia hirsuta
10%
Tephrosia
reptans
6%
Vigna vexillata
10%
Zornia glochidiata
2%
Crotalaria
laburnifolia
2%
Crotalaria
cylindrostachys
4%
Chamaecrista
mimosoides
4%
Chamaecrista
absus
4%
The$Indifallow$Concept:$$
Indigenous$legumes$under$high$rainfall$
Crotalaria
microcarpa
<1%
Chamaecrista
absus
2%
Zornia
glochidiata
10%
Tephrosia
radicans
6%
Rothia hirsuta
26%
Indigofera
vicioides
<1%
Indigofera wildii
2%
Indigofera
praticola
5%
Indigofera
demisa
12%
Indigofera
astragalina
37%

7. University of Zimbabwe
2. Managing different quality organic
resources for improved soil health
and efficient use of external inputs using ISFM
 Farm-available organic resource
chemically classified into three
different quality soil organic matter
inputs:
 Pinus patula sawdust: low (<2% N,
>15% lignin and >4% Polyphenols)
 Maize stover, cattle manure &
Calliandra: medium
 Crotalaria : high (> 2% N, <15% lignin
and < 4% polyphenols)
 Applied to soil annually in same
quantities into maize plots over 12
years

8. University of Zimbabwe
Experiment demonstrated:
 Unsustainability of
monocropping
despite consistent
fertilizer use
 Continuous decline
in exchangeable
base nutrients
 Declining use
efficiency of
macronutrients
supplied in
fertilizers (hence
increased rated)

9. University of Zimbabwe
Organic matter management for
enhanced soil health: Case of nematodes
and N-rich organic resources in maize
0
10
20
30
40
50
60
70
80
Mean Nematode Count (10g-1
maize root dry matter)
-50
0
50
100
150
200
250
300
350
Change in Mean Nematode
Count (100g-1 soil)

10. University of Zimbabwe
3. Using agro-ecological principles to
reclaim degraded soils: Farmers often
abandon field due to loss of productivity
Kick-starting
productivity through
Indifallows
(Nezomba et al.,
2010)

11. University of Zimbabwe
Restoration of degraded soils...
Sequencing of ISFM options
enhanced crop yield response
to fertilizer application:
reducing demand for high
external inputs (Nezomba,
Mapfumo et al., 2015)

12. University of Zimbabwe
ISFM sequencing helping to build soil P capital in
the short-medium term
Nezomba et al., 2014,
Exp.Agriculture

13. University of Zimbabwe
4.Intercropping, rotational and mixed
cropping systems sustaining yields and food
provision for most African farming families
Potential for integrating trees - which species???

14. University of Zimbabwe
5. Soil geochemistry applications for
for agriculture and health
 Study focusing on soil geochemistry and agrobiodiversity
with empahasis on Zn, Fe, Se and I in southern Africa
 Funded by DFID and Royal Society (UK)
 The agroecology framework seen as holding promise
against industrial bio-fortification for improved human
health and wellbeing in Southern Africa
 Three countries participating

15. “There is a critical need for investment into
more scientific research to support agro-
ecology in Africa and improve food and
nutrition security for millions of households”

16. University of Zimbabwe
THANK YOU