Conservation Agriculture concepts and principles

Realizing sustainable agricultural mechanisation

African Conservation Tillage Network

By: Peter Kuria

2nd November 2017

Conservation AgricultureConcepts and Principles


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


1.Easier to double yields in Africa (say from 1.2 to 2.4 tonnes/ha)

2.A 1% increase in cereal yield can lift 2 million people out of poverty

3.Africa has 60% of the global total uncultivated crop land

4.The Question is How?

THE GOOD NEWS:


Historical Perspectives

Ploughing of the virgin lands led to the “Dust

Bowls” in the United States in the 1930

40 million hectares destroyed,

2.5 million people migrated


What is Conservation Agriculture?

Three principles

No or minimum soil

disturbance

Permanent soil cover

Crop & cover crop rotations

and associations

Maximum and sustainable

benefits derived when the 3

principles overlap


A = Absence of soil tillage: No mechanical soil disturbance

B = Cover of the soil: Permanent cover with residues

C = Biodiversity: Crop rootation and/or associations

More: CA is not only the 3 principles

CA SYSTEMCA SYSTEM

A B C


The 3 CA principles MUST be complimented by

GAP enhancers.. (which are however not CA)!

1. Good agronomic practices

o Timely planting; Proper plant spacing

o Effective weed control (with and without herbicides)

2. Use of improved external inputs

o Improved seeds

o Judicious use of fertilisers and pesticides. No shame.

o Could be organic CA. Be ready to develop packages

3. Crop – livestock integration. Not a threat to CA.

4. Agro-forestry – fertiliser trees, fodder, fruit, live fences, wind breakers.

5. Mechanization


Related terminologies

Conservation Agriculture (CA)

Conservation Farming (CF)

Conservation Tillage (CT),

Minimum tillage (MT),

NT No-tillage (never tilled)

Direct-seeding (DS)

Direct-seeding on vegetal mulch


Why Zero or Minimum Tillage?

Tillage or ploughing – is the most time and power consuming

operation is avoided, saving costs and time

Undisturbed weed seeds remain in the soil without germinating –

reducing weeds

Ploughing disturbs the soil – making it susceptible to erosion by

water and wind; causes plough pans

Ploughing releases CO2 contributing to climate change


Minimum soil disturbance

The “Deceiving” effects of ploughing

IMMEDIATE EFFECTS

• Weeds are controlled

• Seedbed is prepared

• Water infiltration improves

• Soil aeration improves

• Nutrients are released, availed

• Incorporation of manure,

fertilizers and organic matter

• Loose soil eroded and nutrients are

leached

LONG TERM EFFECTS

• Depleted soil organic matter

• Damaged soil structure and macro pores

• Soil flora and fauna disappear

• Hard/plough pan formation

• Acute soil water availability and restricted

aeration

• Distortion of pH levels

• Decline in nutrient availability


More tractors needed, but not for ploughing

Not to rob our grand

children of their future!

Not to lose Carbon


CA is needed now, in … Adapting to climate change

Tillage accelerates decomposition of soil and soil

surface organic matter into CO2. No till reduces CO2.

emissions

CA fosters: carbon sequestration, maintenance of

hydrological cycle and biological pest control

Although smaller amounts of carbon can be

sequestered per hectare (0.05 – 0.2 metric tons ha-

1yr-1), with thousands of farmers practising, benefits

are huge.

BURNING = PLOUGHING


When zero “tillage” means plenty


…taking advantage of macroporosity

Water infiltrates...


Zero till Conventional

35% more infiltration

Field soil measurement


Tillage effects on water infiltration and ground cover

120.8Moldboard plow

271.3Chisel Plow

482.7No-till

Ground cover

(%)

Water

infiltration

(mm/minute)

Tillage type


What equipment for Conservation Agriculture?

Hand tools: Jab

planter, hoe, stick

Oxen rippingOxen direct seeding

Tractor mounted seeder

Tractor mounted seederHighly mechanized

Start with what farmers have


Let the roots and soil flora and

fauna do the work


Concepts of Agricultural production and management

(Derpsch and Moriya, 1999)OLD PARADIGM

Soil tillage is good for crop production

Crop residue is a waste product –burn/bury

them with tillage implement

Bare soil for months and years is good farm

sanitation

Focus on soil chemical processes

Chemical pest control is the first option

Soil erosion is acceptable and unavoidable

risk in farming

NEW PARADIGM

Tillage is not necessary for crop production

Crop residues are valuable products and must

remain on soil surface as mulch

Permanent soil cover is essential

Focus on biological soil processes

Biological pest control be first option

Soil erosion is a symptom that unsuitable

methods are being practiced at the source

•Under new paradigm i.e. sustainable land use e.g. CA ensures

ecological, social and economical sustainability.


SOIL COVER- the most important principle?? -

Soil cover by crop residues (dead

plant matter) or imported mulch

Soil cover by cover crops

Soil cover by living plants –

synchronized for all year round

production


Soil cover by cover crops -

• Intercropped cover• Imported mulch


All-year round cover: MAIN AND COVER

CROP


Why soil cover?

More soil organic matter and available nutrients

Promotes biological activity-soil organisms (earthworms, insects,

rodents, microbes) leading to increased humus (decomposed organic

matter)

Increased humus leads to soil enrichment & improved soil structure

(aggregation/ pores)

Increased water infiltration, decreased water evaporation, water (&

nutrient) holding capacity


Why soil cover?

Cushions temperature changes-dampening extremes

Better root penetration and crop growth

Less soil erosion from both water and wind

More– less fluctuating temperatures

Less weed pressure


Permanent soil cover

Maize > Tephrosia

relay after 8 months

Maize –Canavalia

Maize – Lablab

You can’t have soil biology without plants as their host.


In drylands the more soil cover, the more water

infiltration and the less soil and water loss


Early crop growth in a mulched soil


Imperata cylindrica controlled by Mucuna


How Much Residue is Enough?10 % 30

%

50

%

90

%

Source: Purdue University


Principle 3 : Rotations and associations


Crop RotationsDefinition:

A planned system of alternating crops aimed at maintaining and

improving soil productivity

• Crop rotations can include commercial and cover crops

o Produces varying quantities & types of residues

o Facilitates residue management


Crop rotations-principles

Basis of a good rotation is alternation of crops:

1. With differing ability to absorb or exhaust

nutrients (e.g. from deeper to top soil layers)

2. With different susceptibility to specific diseases

3. Based on considerations of beneficial or

detrimental effects of crop on following crop

4. Different peak requirements for inputs such as

labour and water


Crop rotations - principles

1. Effects on the succeeding crop due to:

2. Moisture

3. Nitrogen and other nutrients

4. Root type and distribution

5. Residue amount for subsequent crop

6. Weeds

7. Pests and diseases

8. Allelopathic toxins

9. Seeding and harvest times

Realizing sustainable agricultural mechanisationRotational schemes for annual crops


Intercropping grain and cover crops

Cereals/grasses and legumes

Cereals/grasses and oil crops

2-3 or more species, more favourable C/N ratio, spreads out

mineralization

Common mixes:

Millets + sorghum

Pigeonpea + sorghum (planted at same time)

Millet/sorghum + Crotalaria juncea

Millets + Cowpea

Maize + Velvet bean (delayed planting of c crop )


Crop mixtures: for weed suppression


Summary

Greater crop production overall

Break pests cycles and control weeds by introducing weed smothering

combinations

Improved nutrient cycling – from deeper layers by trees and shrubs to

crop rooting zones

Diversification of crops in rotations may mitigate against dry spells and

some crop failures

Balance amount and quality of residues for soil cover from legumes,

cereals, high and low biomass crops


Some basic implications


Integrated

holistic approach !

Management

Cover crop Rotations

Improved water

harvesting and retention

Improved nutrient recycling

Net accumulation

of Soil Organic matter

No soil

disturbance


More roots…


Biological activity

is restored; soil fauna

is back...


Promote soil biological life,

it is the engine room of your soil

Soil biota decompose plant

residues and promote soil fertility,

nutrient cycling, soil structure,

water infiltration, water holding

capacity, soil aeration, and filters

and suppresses soil-borne

pathogens and pest organisms

of your farm by:

• Avoiding high application rates of acidulated, salt-based and nitrogenous fertilizers

• Applying conditioner (“smart”) fertilizers and other additives that promote, rather than retard, soil life

• Maintaining good soil aeration


Soil pH stabilises …

Soil acidification is normalised by:

- build up of soil organic matter

- minimum (optimal) use of mineral fertilisers

Effects:

- nutrient availability to plants increase/broaden

- toxicities eliminated

- range of crops that can be grown increase

- soil biodiversity increase/rich


Field soil measurement

Soil slaking & dispersion

When water is added to soil:

- slaking; the breakdown of aggregates into

microaggregates (REVERSIBLE)

- dispersion; the breakdown of aggregates into the

primary soil particles of sand, silt and clay

(IRREVERSIBLE)


Soil health

• contains many beneficial organisms

• better movement of air, water and nutrients

• more nutrients are available

• porous soil allows better root development

Healthy soil


Applicability

Realizing sustainable agricultural mechanisation LABRANZA PÓS COSECHA DE

Sweet pepper

Cassava

CA is applicable to virtually all cropsOnionsCucumber

Tomato Squash


LABRANZA PÓS COSECHA DE

CA is applicable in different

agroecological situations

Wet or dry areas

Slopes

Rain or irrigated systems


Challenges

• Crop-livestock integration


Challenges

• Weeding


Challenges• Labour


How can we facilitate learning of

these facts/benefits to trainers and

farmers?


Worldwide adoption of

Conservation Agriculture

6thSSource World Congress on Conservation Agriculture, Winnipeg, 22-25 June 2014 slide 2/x

USA 36

Canada

18

Australia 17.9

Europe 2

Kazakhstan 2

Africa 1.2

Brazil

32

Conservation Agriculture globally 157 Million ha (~11% of arable cropland)

Argentina 27

Paraguay 3

China 6.7

tropical savannah

continental, dry

temperate, moist

temperate, moist

continental, dry

irrigated

smallholder

smallholder

smallholder

arid

arid

large scale

large

scale

large scale

large scale

large

scale

large

scale

subtropical, dry

tropical savannah

other LA 2.4

>50% W

(40%)

20%

99%

100% West

(36%)

Russia,

Ukraine 5.2

India 1.5

other Asia 0.1

• CA adoption expanding at the rate of 9 million ha annually

• 1.22 million ha in Africa. 65% are smallholders.

• 19,000 smallholders in East Africa are beneficiaries of South-South Partnership

Source: Adapted from

Kassam, 2015


Worldwide adoption of

Conservation Agriculture

6th World Congress on Conservation Agriculture, Winnipeg, 22-25 June 2014 slide 2/x

100

Dustbowl

1930 20001950

US

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(US

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erc

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str

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History and Adoption of CA

1970 2010

155 mill ha

firs

t n

o-t

ill fa

rmers

in

US

A

Fir

st

WC

CA

in

Ma

dri

d

Source: Kassam, 2015


CA Adoption Studies and Impact

Documentation in AfricaAlgeria

0%Ghana

1%Kenya

1%Lesotho

0%Madagascar

0%Malawi

8% Morocco0%Mozambique

6%Namibia0%

South Africa65%

Sudan0%

Swaziland0%

Tunisia0%

Uganda0%

Tanzania1%

Zambia12%

Zimbabwe4%

% of Area under CA (Africa)

Algeria

Ghana

Kenya

Lesotho

Madagascar

Malawi

Morocco

Mozambique

Namibia

South Africa

Sudan

Swaziland

Tunisia

Uganda

CA now adopted in more than 20 countries in Africa as core production component of CSA

Estimated Cropland under CA in Africa is 2.68 Mha.

Area under CA has increased by 447% since 2008/09.

> 95% of the farmers are smallholders -1ha

Of the land under CA: 30% smallholders, 1% medium, 69% large-scaleSome 2.5% of the cropped land is under CA.


CA for challenging situations

• Ameliorate plough pans and soil compaction

• Support developing physical structures for erosion control

• Consider Agroforestry

• Amend soil degradation

• Others?

Pre-conditions to implementation of CA


Ameliorate plough pans and soil

compaction

• Sub-soiling

• Planting basins

• Biological tillage using cover crops with tap roots: Cajanus cajan, Dolichos lablab,


Develop physical structures for erosion control

• Stone bunds

• Contour bunds

• Cut off drains

• Permanent ridges


Permanent wide (2 m) beds



Contour bunds


Consider Agroforestry

• Fertiliser trees (Faidherbia albida, )

• Multi-purpose trees for fruits, fuel wood, building materials

• Live fences

• Wind breakers


• Addition of lime or manure

• Leguminous cover crops

• Proper drainage

Amend soil degradation (low pH, sodic soils, chemical

toxicity, )


Challenges to CA

• Change of mindset. Need champions/role models.

• Crop residues to keep the soil covered. Crop-livestock integration.

• Weed control. Researching & contextualizing options.

• Land tenure

• Adaption of CA to suit local conditions and needs. CA is Knowledge intensive as

opposed to power intensive conventional farming

• Poorly addressed ecosystem/watershed and external environmental issues (produce

markets, value addition, and climate change variability)

• Enticing commercialization of production (farming as a business).

• Inconsistencies in Government policy support


Brachiaria undersown in

maize


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Conservation Agriculture concepts and principles