Soil health for soil and water management in Conservation Agriculture

Realizing sustainable agricultural mechanisation
Soil Health for Soil and Water
Management in Conservation Agriculture
Amir Kassam
ACT, University of Reading (UK) and FAO
Training Manuals Pretesting Workshop, Comprehensive Conservation Agriculture Programme,
Ministry of Agriculture, Water & Forestry, Rundu, Namibia, 23-27 October 2017

1.Historical perspectives
2.What is Conservation Agriculture (CA)?
3.Terminologies related to CA
4.Application of the CA principles
5.Opportunities for CA systems
6.World adoption trends of CA
7.CA for challenging situations
8.Overall challenges
Contents

Food Security more urgent in Africa in
coming years
1.Global pop. to increase by 33% to 9 billion by 2050
2.Africa’s to increase by 115%; by 21% in Asia
3.60% more food worldwide; 100% in Africa
4.Worldwide hunger decreased by 132 million in last 20 years; it
increased by 64 million in Africa.
5.Threatening climate change challenges
6.Farming related land resource degradation

Soil degradation world map – GLASOD (FAO 2000)
Millennium Ecosystem Assessment 2005 – 89% our ecosystems degraded or severely degraded, only 11%
in reasonable shape.
“soil degradation can get us before climate change does”
All agricultural soils show signs of degradation

“Dirt – the erosion of civilizations”
by David R. Montgomery
(Prof. of Earth and Space Sciences at the University of Washington in Seattle, leads
the Geomorphological Research Group, member of the Quaternary Research
Centre):
• Soil is a thin skin of earth
• Soil formation is very slow
• In human history entire empires have
disappeared due to soil degradation (Greeks,
Romans, Maya etc.)
• Soil tillage was the first agricultural operation
performed.
• Any level of continuous mechanical soil
tillage results in degradation processes
exceeding by far the natural soil formation
processes
= Not sustainable

BUT Conventional land preparation
regular tillage, clean seedbed, exposed
Effects:
• Loss of organic matter
• Loss of pores, structure soil compaction
• Destruction of biological life & processes
6

Rothamsted Research
LEAF’s Simply Sustainable
Soils Solution for improving
sustainability of land.
It’s not the terrorists on both sides who
are destroying civilizations, it’s the
plough!
Six simple steps for your soil to help
improve the performance, health and
long-term sustainability of your land.
Root cause of degradation

25cm
30cm
10cm
But underneath?

Tillage-induced Carbon Dioxide Loss
and wind erosion
CO2CO2
Reicosky
9

Dust storms& sand dunes in GBAO, Tajikistan (April 2015)
10

Residue retention distinguishes CA
from conventional farming systems
soil crusts – no mulch low
SOM
CLODS OF TOPSOIL FROM
ADJACENT PLOTS

Tajikistan – April 2015

With rice ……
13

Rain
Run-off
(erosion)
leaching
Soil Structure
Organic Matter
Soil Biota
Soluble elements
of organic or synthetic origin
Tilled soil Not-disturbed soil
Destination of Rainwater

TILLAGE AGRICULTURE -- Erosion
15

16
Google image, 16 February 2014

(Brisson et al. 2010)
Stagnating Yields (yield gap)
Rising-plateau regression analysis of wheat yields throughout various
European countries
17
But inputs and input costs going up, diminishing returns setting in,

Runoff and soil erosion – Andalusia,
Spain

FOR AGRICULTURE (AND SOCIETY)
• Higher production costs, lower farm productivity
and profit, sub-optimal yield ceilings, poor
efficiency and resilience
FOR THE LANDSCAPE (AND SOCIETY)
• Dysfunctional ecosystems, loss of biodiversity,
degraded ecosystem services -- water, carbon,
nutrient cycles, suboptimal water provisioning &
regulatory water services etc.
19
Consequences of tillage-based agriculture
at any level of development

What happens in a tilled soil?
• it loses cover and protection
• reduced biodiversity: more bacteria, less major species
• oxygen is added, accelerating decomposition of organic
matter; water soluble nutrients are released
• connected macro pores are destroyed; water infiltration
rates reduced;
• aggregate stability destroyed, water & nutrient retention
capacity destroyed
• contaminated waters leave as surface runoff with soil,
organisms, nutrients (mineral or organic origin), pesticides,
and as groundwater with leached minerals
The root problem:

Instead: What happens in an undisturbed soil?
• Soil formation, minimal erosion, reversed degradation
(1 mm soil/year)
• Increase of SOM
0.1-0.2% per year
• Soil structure is formed
by action of soil biota
(roots, fungi, fauna)
• Better adaptation to extreme
rainfall events through better
infiltration (less flooding even without
terraces and reservoirs)
• Better adaptation to drought: more SOM = more water,
deeper rooting, less water evaporation losses
• Better soil-mediated ecosystem services

A healthy soil is a living biological system

Soil health -- Definition
Soil health is the capacity of soil to function as a vital living
system, within ecosystem and land use boundaries, to sustain
plants and animal productivity, maintain or enhance water and
air quality, promote plant and animal health …… Management
of soil health thus becomes synonymous with ‘management of
the living portion of the soil to maintain the essential
functions of the soil to sustain plant and animal productivity,
maintain or enhance water and air quality, and promote plants
and animal health’ (Trutmann, 2000, Cornell)
Soil quality ~ soil health

Soil health -- Definition
Soil health refers to the integration of biological
with chemical and physical approaches to soil
management for long-term sustainability of crop
productivity with minimum negative impact on the
environment. Healthy soils maintain a diverse
community of soil organisms that help to control
pests, form beneficial symbiotic associations with
plant roots, recycle essential plant nutrients,
improve soil structure…… (Wolf, 2000)
Soil quality ~ soil health
soil health

25

Soil food
webs…..
Plus food
webs
above
ground
Pest-
predator
dynamics

Soil productive capacity (vs. fertility) is derived from several components which interact
dynamically in space and time:
• Physical: architecture - pore structure, space & aeration
• Hydrological: moisture storage -
infiltration
• Chemical: nutrients,
CEC, dynamics
• Biological: soil life and
non living fractions
• Thermal: rates of biochemical
processes
• Cropping system: rotation/association/sequence
A productive soil is a living system
and its health & productivity depends
on managing it as a ‘complex’ biological
system, not as a geological entity.

Water and healthy soil
In CA soils
• Soil surface open
• 50-60% air space
• 50% of this air space can hold moisture
In tilled soil
• Soil surface closed
• 10-30% air space
• <30% of air sapce can hold water

Soil formation
• The rock and subsoil upon which the
multilayered soil horizons sit weathers from
the bottom but the soil itself as a living system
forms from the top through biological
processes involving soil fauna and vegetation
as permitted by the prevailing moisture and
temperature conditions.
• The biological processes of soil formation are
influenced by the parent material, climate, and
vegetation, and in agricultural soils, by how
the producer manages the soil under the altered
conditions.
background

Major soils
37% Arenesols
27% Leptosols
6% Cambisols
8% Regosols
82 M ha

Arenosols are sandy-textured soils that lack any significant soil profile development. They exhibit only a
partially formed surface horizon (uppermost layer) that is low in humus, and they lack subsurfaceclay
accumulation. Given their excessive permeability and low nutrient content, agricultural use of these soils
require careful management. They are found in arid regions of the earth.

Leptosols
A Leptosol is a very shallow soil over hard rock or highly calcareous material or a
deeper soil that is extremely gravelly and/or stony.
Leptosols are unattractive soils for rainfed agriculture because of their inability to
hold water,[1] but may sometimes have potential for tree crops or extensive grazing.
Leptosols are best kept under forest.

Cambisols are characterized by the absence of a layer of accumulated clay, humus, soluble salts, or
iron and aluminum oxides. They differ from unweathered parent material in their aggregate
structure, colour, clay content, carbonate content, or other properties that give some evidence of
soil-forming processes. Because of their favourable aggregate structure and high content of
weatherable minerals, they usually can be exploited for agriculture subject to the limitations of
terrain and climate.

A Regosol is very weakly developed mineral soil in unconsolidated materials.
Regosols are extensive in eroding lands, in particular in arid and semi-arid
areas

her
● Fotos grandes.
Solo arrastra
una nueva
imagen y
pásala para
átras
Path to waterfall on private property brings income to locals in
the form of ecotourismMonteverde Cloudforest Reserve
provides important source of
water in landscape and
downstream
Windbreaks provide habitat and
corridors for wildlife, control
erosion and protect livestock from
wind
Shaded coffee extends wildlife habitat from reserve and
reduces erosion
All fences are live rows of trees
Coffee, corn, sugar cane and other products are
sold at a local cooperative
Ecoagriculture landscapes: harmonizing multiple
objectives at farm, community, landscape scales

Ecosystem services
Water cycling Carbon cycling Atmospheric circulation
38
Source: The Millennium Ecosystem Assessment (2005)

Length of rainfed growing period zones

FOR AGRICULTURE (AND SOCIETY)
• Higher production costs, lower farm productivity
and profit, sub-optimal yield ceilings, poor
efficiency and resilience
FOR THE LANDSCAPE (AND SOCIETY)
• Dysfunctional ecosystems, loss of biodiversity,
degraded ecosystem services -- water, carbon,
nutrient cycles, suboptimal water provisioning &
regulatory water services etc.
40
Consequences of tillage-based agriculture
at any level of development

The New Paradigm of Sustainable Intensification
Technical objectives of SI
• Agricultural land productivity (output)
• Natural capital and flow of ecosystems services
Simultaneously
• Enhanced input-use efficiency
• Use of biodiversity – natural and managed
(and carbon) to build farming system resilience (biotic and abiotic)
• Contribute to multiple outcome objectives at farm, community & landscape scales
And
• Capable of rehabilitating land productivity and ecosystem services in degraded
and abandoned lands
But how to achieve such multiple objectives?

CA totally compatible with
the objectives of SI
What does CA offer: Mobilizing
greater crop and land potentials
sustainably?
42
Switching to sustainable solutions

Concept:
CA is a no-till production system.
It is defined by three interlinked
principles (to correct what is missing):
1. No or minimum soil disturbance
(permanent no-till seeding & weeding).
2. Permanent organic soil cover.
3. Diversification of species in rotations, sequences or associations.
Along with other GAPs  SPI
Conservation Agriculture

Ecological foundation for sustainable agriculture
production is provided by application of Conservation
Agriculture principles
No/Minimum
soil disturbance
Soil Cover Crop Diversity

Conservation Agriculture – Ecological foundation
…alone do not respond to all the challenges
of achieving a Sustainable Intensification.
They needs to be complemented by all
good practices known.
But CA practices provide an ecological
base or foundation for Sustainable
Intensification as a necessary
set of conditions.
No/minimum
soil disturbance
Soil Cover Crop Diversity
Integrated
Pest
Management
Integrated
Plant
Nutrient
Management
Integrated
Weed
Management
Integrated
Water
management
Sustainable
mechanization
Compaction
management,
CTF
Permanent
Bed and
Furrow
Systems
System
of Rice
Intensification
Good seed
Genetic potential
Genetic resources mgmt.
Pollinator/
Biodiversity
management
Sustainable
land management

What does CA do
Crop
Diversity
No-Till
plus OM
Management
Soil
structure &
biota
Nutrient &
water
cycling
Plant
Insect pests
& diseases
Weed
management
Ecological
Processes
Spiral of
Regeneration &
Intensification
Integrated
CA systems
Anderson, R.L. 2005

Table 1 Effects of CA components fully applied together
(Friedrich et al., 2009)

Conservation Agriculture
CROP
• Increased & stable yields, productivity,
profit (depending on level and degradation)
• Less fertilizer use (-50%), also no fertilizer
less pesticides (-20->50%), also no pesticides
• Less machinery, energy &
labour cost (50-70%)
• Less water needs (-30-40%)
LAND
• Greater livestock and human carrying capacity
• Lower impact of climate (drought, floods, heat, cold) &
climate change adaptation & mitigation
• Lower environmental cost (water, infrastructure)
• Rehabilitation of degraded lands & ecosystem services
Wheat yield and nitrogen amount for different
duration of no-tillage in Canada 2002 (Lafond
2003)
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 30 60 90 120
nitrogen (kg/ha
Grainyield(t/ha)
20-year no-tillage
2-year no-tillage
Patterns of benefits with CA – small or big farms

COMPARISON
A FARMER’S TRIAL – CLODS OF TOPSOIL FROM ADJACENT PLOTS,
PARANÁ, BRAZIL (Shaxson 2007)
PRO-BIOTIC ▲ ANTI-BIOTIC ▲
Topsoil after 5 years with retention Topsoil after regularly-repeated disk
of crop residues and no-till seeding. tillage, without retention of residues
Soil health and adverse effect of tillage agriculture

WHAT DOES IT LOOK LIKE CLOSE-UP?
SAME SOLIDS - DIFFERENT SPACES
IMPLICATIONS FOR ROOTS AND RIVERS
Shaxson (2007)
Soil health & adverse effect of tillage agriculture

SOIL CARBON – Mr. Reynolds’ farm in Lincolnshire
52

Residue retention distinguishes
Conservation Agriculture from
conventional farming systems, which
are characterized by leaving the
soil bare and unprotected, exposed
to climatic agents.

Realizing sustainable agricultural mechanisation (THOMAS, 2004)
Water infiltration, just after a thunderstorm

Situation in Malawi – Tilled & CA
Tilled CA

Gains in Rainfall Infiltration Rate with CA
Less flooding – improved water cycle
Landers 2007
tillage + cover, measured
no-till + cover, measured
tillage, no cover, measured
tillage + cover, calculated
no-till + cover, calculated
tillage, no cover, calculated
Time (min.)
AccumulatedInfiltrationrate[mm.h-1]
Benefits of CA

Plough No-tillage
57

Longer term maize grain yields on farmers fields
in Malawi – Lemu -- CSA
Harvest year
2007 2008 2009 2010 2011 2012
Maizebiomassyield(kgha
-1
)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Conventional control, maize (CPM)
CA, maize (CAM)
CA, maize/legume intercropping (CAML)
a
a
a a
b
b
aa
b
b
a
a
b
a
a
b
a a

Regional perspective – Southern Africa
Conventional tillage yield (kg ha-1
)
0 2000 4000 6000 8000
Conservationagriculturetreatmentyield(kgha-1
)
0
2000
4000
6000
8000
Planting basins, Mozambique
Jab planter, Mozambique
Direct seeding, Zimbabwe
Ripper, Zimbabwe
Direct seeding, Zambia
Ripper, Zambia
Direct seeding, Malawi
Intercropping, Malawi

Longer term maize grain yields on
farmers fields in Malawi - Zidyana
Zidyana
Year
2005 2006 2007 2008 2009 2010 2011 2012
YielddifferencebetweenCAandCP(kgha
-1
)
-4000
-2000
0
2000
4000
6000
CAML
CAM
C
CIMMYT– Thierfelder et al.
Recall what happens when someone falls ill or becomes a drug addict? It takes time
to bring the person back to health, and similarly it takes time to bring the soil back health

Earthworm population
0
50
100
150
200
250
300
plough no-tillage natural
meadow
biomassg/m2
other species
Lumbricus

Biodiversity
Soil food
webs…..
Above
ground
food webs
&habitates
for natural
enemies of
pests
Ground-
nesting
birds,
animals
and insects 62

Source: Dijkstra, 1998
Empirical evidence: The Frank Dijkstra farm in
Ponta Grossa, Brazil – Sub-humid tropics
63

 Wheat yield response to nitrogen fertilization (according the model)
Carvalho et al., 2012
International Scientific Conference: The role of agriculture in providing ecosystem and societal services
Balti Alecu Russo State University, Moldova, 25, Nov. 2014

Economic viability-Malawi
Lemu Zidyana
CP CA CAL CP CA CAL
Gross Receipts 528.6 881.5 979.7 1047.2 1309.5 1293.7
Variable costs
Inputs 238.5 341.0 353.6 221.7 323.7 346.1
Labour days (6 hr days) 61.7 39.9 49.4 61.7 39.9 49.4
Labour costs 159.5 103.2 127.9 155.6 100.7 124.7
Sprayer costs 1.7 1.2 1.7 1.2
Total variable costs 398.1 445.9 482.8 377.3 426.1 472.1
Net returns (US$/ha) 130.5 435.5 497.1 669.9 883.3 821.9
Returns to labour (US$/day) 1.8 5.2 4.9 5.4 9.8 7.6
Source: Ngwira et al., 2012

SUMMARY OF ANNUAL EXPENSES
70
40
60
77,5
85
REDUC-
TION
(%)
15 000 €25 000 €Labour
18 347,55 €61 068,88 €TOTAL ANUAL
7 110 €17 460 €Fuel
1 840,40 €8 158,41 €
Maintenance and
repair of tillage/
drilling implements
1 507,15 €10 450,47 €
Maintenance and
repair of tractors
DIRECT
DRILLING
(Year 2003)
CONVENTIONAL
TILLAGE
(Year 2000)
70
40
60
77,5
85
REDUC-
TION
(%)
15 000 €25 000 €Labour
18 347,55 €61 068,88 €TOTAL ANUAL
7 110 €17 460 €Fuel
1 840,40 €8 158,41 €
Maintenance and
repair of tillage/
drilling implements
1 507,15 €10 450,47 €
Maintenance and
repair of tractors
DIRECT
DRILLING
(Year 2003)
CONVENTIONAL
TILLAGE
(Year 2000)
Instituto de Agricultura Sostenible CSIC , Cordoba, Setiembre 2005
Farm power – 4 tractors with 384 HP under tillage & 2 tractors with 143 HP under no-till
Farm near Evora, South Portugal
66

Two Questions
Groups 1-3
Given the wide range of benefits arising from a healthy
agricultural soil, identify and explain its key productivity
enhancing properties or indicators.
Groups 4-6
Given the built-in integrated soil and water management
practices in CA systems, how can CA systems benefits from
traditional soil and water conservation methods?

Management of soil mulch cover in CA systems

Soil mulch cover
• Comprises stubble, any plant biomass on the soil surface
• 30% soil cover reduces runoff and erosion by 80% -- minimum
desirable cover
• Crop residue cover required continuously to enhance soil
health/life and productivity, and build and protect the soil.
• Residue cover plus cover crops in CA systems contribute to
integrated weed control and insect pest control, and to crop
health.

Soil mulch management
• Soil mulch cover contributes to water, nutrient and
carbon cycles.
• Cover crops can provide biomass for soil mulch
development while enhancing soil health and
productivity
• In dry areas in Nambia, tine seeders would be able
to cope with low levels of crop residues but some
tine seeders can cause medium to high soil
disturbance
• Disk seeders would better manage higher levels of
mulch cover and cause low soil disturbance.
• Cover crops can be single or mixtures, planted sole
or in mixed cropping.

CA is applicable to all crops & cropping systems:
Cropping systems:
soya
wheat
corn
vegetable
rice
potato
perennials
agroforestry

72Two-wheel no-till seeder – small
farmers, Bangladesh
No-till rice
In North Korea
Multi-row tine ‘Happy Seeder’ –
medium farmers, India
No-till rice
In Bihar India

CHINA: innovation with raised-bed, zero-till SRI field;
measured yield 13.4 t/ha; Liu’s 2001 yield (16 t/ha) set
provincial yield record and persuaded Prof.Yuan Longping
73
CA-SRT rice-based system, Saguna Baug,
Maharastra, India – Mr. Chandrashekhar

All crops can be seeded in no-till systems Potatoes
under no-till after rice in North Korea
(Friedrich, 2006)
74

Mechanized or manual

Rehabilitation of degraded
rangelands
Opportunities – Gissar, Tajikistan

• Erosion: North America,
Brazil, China
• Drought: China, Australia,
Kazakhstan, Zambia
• Cost of production: global
• Soil degradation: global
• Ecosystem services: global
• Climate change A&M: global
• Sustainable intensification: global
Spread is farmer-led but needs
policy & institutional support
77
Drivers for adoption of CA

Group questions
Given your understanding of Conservation Agriculture (CA), formulate up to three
CA cropping systems that would be: market responsive, socially desirable and be
capable of producing enough biomass to develop soil mulch and meet livestock
feed requirements.

CA-agriculture of the future – the future of agriculture
More information
amirkassam786@googlemail.com
http://www.fao.org/ag/ca
http://www.fao.org/ag/save-and-grow
Join the CA-CoP!
Thank You!
June 2011

Our Contacts
THANK YOU FOR LISTENING
Website: www.act-africa.org
Email: info@act-africa.org
Twitter: www.twitter.com/ACTillage

Soil health for soil and water management in Conservation Agriculture

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