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 KassamACT, 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)

leachingSoil 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 2014Sediment Plumes – The Guardian


(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 formedby action of soil biota(roots, fungi, fauna)

• Better adaptation to extreme rainfall events through betterinfiltration (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


A healthy soil is a living biological system


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.

https://en.wikipedia.org/wiki/Soil

https://en.wikipedia.org/wiki/Rock_(geology)

https://en.wikipedia.org/wiki/Calcareous

https://en.wikipedia.org/wiki/Gravel

https://en.wikipedia.org/wiki/Stone

https://en.wikipedia.org/wiki/Agriculture

https://en.wikipedia.org/wiki/Leptosol#cite_note-1

https://en.wikipedia.org/wiki/Tree

https://en.wikipedia.org/wiki/Grazing

https://en.wikipedia.org/wiki/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.

https://www.britannica.com/science/clay-geology

https://www.britannica.com/science/humus-soil-component

https://www.merriam-webster.com/dictionary/aggregate

https://www.britannica.com/science/climate-meteorology


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

https://en.wikipedia.org/wiki/Soil

https://en.wikipedia.org/wiki/Erosion

https://en.wikipedia.org/wiki/Arid

https://en.wikipedia.org/wiki/Semi-arid


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 interlinkedprinciples (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 allgood practices known.But CA practices provide an ecological base or foundation for Sustainable Intensification as a necessaryset of conditions.

No/minimum soil disturbance

Soil Cover Crop Diversity

IntegratedPest

Management

IntegratedPlantNutrientManagement

IntegratedWeed

Management

IntegratedWater management

Sustainablemechanization

Compaction management,CTF

Permanent Bed and

FurrowSystems

Systemof RiceIntensification

Good seedGenetic potentialGenetic resources mgmt.

Pollinator/Biodiversity

management

Sustainableland management


What does CA do

Crop

Diversity

No-Till

plus OM

Management

Soil

structure &

biota

Nutrient &

water

cycling

Plant

Insect pests

& diseases

Weed

management

EcologicalProcesses

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

Gra

in y

ield

(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 diskof 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 CALess 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.)

Ac

cu

mu

late

d I

nfi

ltra

tio

n r

ate

[m

m. 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

Maiz

e b

iom

ass y

ield

(kg

ha

-1)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Conventional control, maize (CPM)

CA, maize (CAM)

CA, maize/legume intercropping (CAML)

aa

a a

b

b

aa

bb

a

a

b

aa

b

a a


Regional perspective – Southern Africa

Conventional tillage yield (kg ha-1

)

0 2000 4000 6000 8000

Conse

rvat

ion a

gri

cult

ure

tre

atm

ent

yie

ld (

kg h

a-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

Yie

ld d

iffe

rence

bet

wee

n C

A a

nd C

P (

kg h

a-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

bio

mass g

/m2

other species

Lumbricus


Biodiversity

Soil food webs…..

Above groundfood webs &habitates for natural enemies of pests

Ground-nestingbirds, 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 andrepair of tillage/drilling implements

1 507,15 €10 450,47 €Maintenance andrepair 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 andrepair of tillage/drilling implements

1 507,15 €10 450,47 €Maintenance andrepair 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 QuestionsGroups 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

cornvegetable

rice

potato

perennialsagroforestry


72Two-wheel no-till seeder – small farmers, Bangladesh

No-till rice

In North Korea

Multi-row tine ‘Happy Seeder’ –medium farmers, India

No-till riceIn 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 needspolicy & 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 [email protected]://www.fao.org/ag/ca http://www.fao.org/ag/save-and-grow

Join the CA-CoP!

Thank You!

June 2011


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soil health for soil and water management in conservation agriculture

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