Conservation
Agriculture
A brief reflection of The Maize Trust supported
research to date
Conservation Agriculture Farmer Innovation Program
19 September 2022
Principles of and motivation for CA
CA PRINCIPLES
1. Minimum mechanical soil disturbance (no-till seeding/
planting and weeding); < 15 cm or 25 % of soil surface.
2. Diversification of cropping system (rotation sand/ or
sequences and/ or associations involving annuals and
perennials, including legumes and cover crops with
maximum living rootsin soil).
3. Maintenance of a permanent organic soil cover (crop
residues and cover crops); minimum 30%, but aim for
100%.
COMPLIMENTARY GOOD PRACTICES
Integration of animals
Integrated soil fertility and acidity management
Integrated weed management
Integrated pest and disease management
Farming systems need to adapt and adress to these chalenges:
Climate change
Biodiversity loss
Declining soil health
Rising costs of production
Declining productivity &
profitability
Rising debt
Risk of defaulting farm failure or
closure
The consequences of deep tillage
practices include 46% of soil organic carbon is lost in SA’s
croplands resulting inseriously degraded soils & reduced
production capacity.
DIFFERENT FARMING SYSTEMS IN SOUTH AFRICA
Conventional tilage (CT) employs various primary and
secondary tillage practices with grazing on the grazing
lands (veld) only.
No-tilage (NT) uses no-tillage planters with simple
rotations, and livestock grazing the same as under CT
(taking place on the veld only).
Conservation agriculture (CA) uses no-tillage practices, but
also employs a more complex crop rotation system,
integrating cash crops with cover crops for the livestock.
Livestock is used intensively in both the grazing area and
croplands.
CA offers an important and practical solution that can:
Adapt & mitigate climate change
Hedge against financial stress
Provide long-term financial viability
Restore soil health
These solutions offer benefits:
Reduce risk & build more resilience
Positive impact on soil & water health
Higher C-sequestration rates (+Credits)
Higher, stable production and
profitability
Improved input use efficiency
(reduced input costs)
Reduced capital, maintenance &
replacement costs
Research approach and implementation
« Farmer-centered Innovation Platforms
scientifically proven to work the best for CA
research (on the left).
Healty soils are the cornerstone of agriculture,
providing FREE functions and services.
HOW DID WE JOIN AND SUPPORT AN EXISTING FARMER-LED
INNOVATION MOVEMENT?
Scientific principles:
On-farm, farmer-centered
Co-learning (by doing)
Continuous interaction and dialogue
Facilitation on all levels
SCIENTIFIC THEORY & APPROACH
GOAL > To facilitate research, development and adaptation
of appropriate CA systems for a range of unique contexts in
South African grain farming regions.
MAIN ACTIVITIES > On-farm research; Creation of wider
awareness and innovation capacity.
KEY INITIATIVE > CA Farmer Innovation Programme (CA
FIP); Grain SA - ASSET Research, The Maize Trust.
CA FIP PROJECT TEAMS & ON-FARM RESEARCH TRAILS
Esri, HERE, Garmin, FAO, NOAA, USGS
Powered by Esri
CA farmer networks, Drs Jaap Knot & Hendrik Smith, Gerrie Trytsman, NWU
> 3 ongoing trails
3Maluti
CA farmer networks, Drs Jaap Knot & Hendrik Smith, Gerrie Trytsman, NWU
> 2 ongoing trails
4Reitz & Vrede
Riemland and
Ascent study groups, VKB, Gerrie Trytsman, NWU, Dr Hendrik Smith, ARC
> 24 completed trails
5Smallholder in KZN
Numerous
farmer learning groups & Mahlathini Development Foundation, NWU
> 40 ongoing trails
The trails...
KEY TRAIL TOPICS
CA vs CT (yields, finance)
Crop density (plant population and row width)
Crop rotations (cash crops)
Cover crops (CC) and Livestock integration
CA implements
KEY INDICATORS MEASURED
Production - yields, biomass, water use efficiency (WUE)
Economics and finances
Soil health (Haney SHT and many other)
Biodiversity, e.g., dung beetles
Carbon footprint
Visual field tests: Erosion/ ground cover, Water infiltration,
slaking, structure, soil profiles & roots, earthworms, weeds,
insects, etc.
LESSONS LEARNED AND IMPLICATIONS FOR NEW ON-FARM
TRAIL DESIGN
New treatments from 2020 onwards:
1. CT: Conventional tillage systems
2. NT: No-till with high inputs and simple rotations e.g., maize
x soya
3. CA with integrated crop-livestock system (ideal, best CA
system) - see below
4. Veld (control)
CA/ RA integrated crop-livestock system (eastern summer
rainfall areas, South Africa)
(LEFT) Season 1: Grain cash crop + relay/ inter cropping +
Livestock (e.g., maize & WCCs)
(MIDDLE) Season 2: Annual Mixed Double Cover crops
(summer + winter) + Livestock
(RIGHT) Season 3: Grain cash crop + WCC + Livestock (e.g.,
soya & WCCs)
CA/ RA integrated crop-livestock system (western summer
rainfall areas, South Africa)
(LEFT) Season 1: Cash crop (e.g., maize)
(MIDDLE) Season 2: Summer Cover Crop + Livestock
(RIGHT) Season 3: Grain cash crop + WCC (intercrop) +
Livestock (e.g., Sunflower & WCCs
Research results: Yield
Maize grain yield and rainfall use efficiency of
conventionally tilled mono-culture and three CA
crop systems on a sandy loam soil during six
consecutive seasons near Ventersdorp in the North
West Province
(Maize Trust funded project from 2008/2009 to
2015/2016)
FACTORS AFFECTING MAIZE YIELD:
No-till with a soil cover of crop
residues: maize in monoculture
increased by 40% over that of the
conventionally tilled system.
Rotating the maize with a legume in
no-till with soil cover, the yield
increase was 45%.
Rotating it with millet and a legume in
a three-year system, the yield
increased was 59%.
These increases are due to the
improved infiltration of rainwater and
less runoff as well as the “rotational
effect” where the yield of maize often improves by rotating
it with other crops.
Similar improvements were found for the rainfall use
efficiency. This is important as rainfall is the most limiting
natural resource.
(Nel, A. (2017). Evaluation of conservation
agriculture principles on two soil types on the
Highveld. Final progress report to The Maize Trust.)
Farm 1: Ottosdal, NWP
Maize yield: conventional tillage versus no-till
Conventional tillage:
Rip-on-row
2 x 2.3 m + 1 x 1.5 m row spacing
20 000 plants per ha
No-till:
Maize + residue cover
0.52 m row spacing
40 000 plants per ha
Results:
The three-year mean no-till maize yield was 1.68 t ha-1
(52%) higher than the conventional yield, mainly due to a
three- to fourfold increase of the water infiltration rate.
(Smith et al., 2018)
Farm 2:
The yield of maize (t ha-1) as affected by cropping system in
the Ottosdal area.
Cropping systems:
CA1: No-till, 2 m spaced rows, 40 000 plants ha-1,
CA2: No-till, 0.91 m spaced rows, 27 000 plants ha-1,
CT1:Moldboard ploughing 0.25 m deep, 0.91 m spaced rows,
24 000 plants ha-1, and
CT2: Rip-on-row 0.45 m deep, 1.5 m spaced rows, 33 000
plants ha-1
Farm 3:
The yield of maize (t ha-1) as affected by cropping system in
the Ottosdal area.
Cropping systems:
CA1: No-till, 2 m spaced rows, 40 000 plants ha-1,
CA2: No-till, 0.91 m spaced rows, 21 000 plants ha-1
CT: Strip tilling 0.3 m wide and 0.25 m deep, 1.5 m spaced
rows, 2 000 plants ha-1
Productivity for smallholders: Yields (Bergville):
Average yields for maize planted in intercropped plots
(M+B , M+CP, M+Pk) are much higher than the yields in
maize only plots.
Average yields for the CA trial plots (intercropped and
maize only averaged) are much higher than maize yields in
the CA control plots (planted to maize only in consecutive
years).
Yield advantages for maize through intercropping
and crop rotation are evident after a continuous
CA implementation cycle of 4 or more years »
Plant density effect on yields (Ottosdal trial results, 2014-2018)
««(left) Density: <24 000 x 0.76-0.9 m:
(lower yields)
Less crop residues
Less roots
More weeds
Lower WUE
»»(right) Density: 40 00 x 0.52 m:
(higher tields)
Quicker build-up of soil cover
More roots
Less weeds
Better WUE
Research results: Integrated crop-livestock systems
and bio-physical aspects
Assessment of cover crops & livestock integration (9 years, CA
FIP projects). The aims were to increase knowledge and
management of CA tools, such as:
Biodiversity: biomass production and adaptability of cover
crop functional groups + multi-specie mixtures
Intensification: green fallow, intercrop and rotation systems
Integration: Livestock (sheep and cattle)
Grazing systems: Intensity and frequency of grazing (HUG)
Key findings on cover crop & livestock integration trials:
Improvementin soil health (water and nutrient cycles)
Increase in the amount and quality of soil cover
Significant improvement in cash crop yield during drought
seasons
Reduction in agro-chemical use, especially fertilizer
without yield penalties
Increased biodiversity (above- and below-ground)
Weight gain from 30% biomass (cattle) - 220-240
kg/ha/summer season
Reduced risk by diverse income generation
Improved financial viability (medium- to long-term)
There is not a right or wrong decision (better or
worse)•Respond to the situation and use the tools - adaptive
management is key
TESTING THE EFFECT OF COVER CROPS ON MAIZE YIELD,
OTTOSDAL
(Smith et al., 2018)
WATER USE EFFECIENCY OF MAIZE, OTTOSDAL, (Smith et al.,
2018)
Effective rainfall values from October to May; Not
considering soil water content before planting and after
harvesting the grain. Average WUE for maize in SA is 8
kg/mm/yr.
MONITORING SOIL HEALTH ON FIXED FARMER-LED TRAIL
SITES (comparing
different systems or ‘treatments')
REITZ
VREDE
CARBON FOORPRINT RESULTS:
Current CO2 emissions for each system vs. the sequestration
potential of transitioning from conventional tillage to No-till
and CA farming systems for Maize per region.»»
(Smith et al., 2021)
The Nett kg CO2e calculated from current emissions and the
sequestration potential for each region in the transition to No-
till and CA systems espectively for Maize. »»
(Smith et al., 2021)
Carbon sequestration website
Carbon footprint videos:
Part 1: Introduction. The carbon footprint of Summer
Maize Farming Systems in South Africa.
Part 2: Carbon Emissions & Carbon Sequestration. The
carbon footprint of Summer Maize Farming Systems in
South Africa.
Part 3: Results from the work completed with The Maize
Trust. The carbon footprint of Summer Maize Farming
Systems in South Africa.
GREENHOUSE GAS EMISSION
CONTRIBUTION FROM PRODUCTION
INPUTS
HOT SPOT: N fertilisers used in CT
systems contributes to 60-70% of the
emissions.
CA AND BIODIVERSITY
DUNG BEETLES
Differences in dung beetle abundance in different
agricultural practices in the Reitz and Vrede areas.
(Smith et al., 2021)
(Smith et al., 2020)
Differences in dung beetle diversity in different agricultural
practices in the Reitz and Vrede areas.
NEMATODE-BASED SOIL HEALTH INDICES:
Measure soil ecosystem (soil food web) health and
functioning
Measure recovery or restoration of soils health
A good indicator of recent changes in soil heath status
Results: Soil food web status in farmlands under CA, Vrede
study area (Loggenberg, 2021).
1st Sampling interval
2nd Sampling interval
Research results: Financial impacts
(Free cash flows (profit), Production costs.)
(Sources: Conv & NT: Grain SA 2021/22 online production
reports. CA/RA: Maize Trust CA field trials 2021/22)
Declining soil health (fertility)..
..leads to increasing input volume requirements
and cost.
This is amplified by rising costs of
fertiliser, agro-chemicals, and overheads.
The combination is unsustainable.
Conservation Agriculture provides the
solutions to overcome these problems
But support is needed through the transition phase
for CT to CA to
strengthen/ fasten the performance and impact of
CA.
CA/RA requires..
..a paradigm shift, awareness, ecological literacy
and an investment in acquiring new knowledge,
skills and tools (livestock and equipment).
MPUMALANGA
Cost comparisons of various farming systems as per
typical production accounts of the Mpumalanga area for
the 2021/22 season.
External inputs = fertilizer, lime, fuel, reparation,
herbicide, pesticide
Sundry inputs = insurance, hedging, interest
Overhead costs = capital, equipment, replacement,
maintenance
Sources:
1. Conv & NT: GrainSA 2021/22 online production accounts
2. RA: ASSET Research in-field trials 2021/22
Cost comparisons of various farming systems for the
Mpumalanga area for the 2032/33 season assuming NO
price increase of fertilizers in 2022.
External inputs = fertilizer, lime, fuel, reparation,
herbicide, pesticide
Sundry inputs = insurance, hedging, interest
Overhead costs = capital, equipment, replacement,
maintenance
Source:
1. Model values:
https://sagrainmag.co.za/2022/05/03/financial-benefits-of-
converting-to-ca/
Cost comparisons of various farming systems for the
Mpumalanga area for the 2032/3 season assuming a once-
off 200% price increase of fertilizers in 2022.
Source:
1. Model values as per the previous, but added a once-off
shock to fertilizer prices of 200%
MALUTI
Cost comparisons of various farming systems as per
typical production accounts of the Maluti area for the
2021/2 season.
External inputs = fertilizer, lime, fuel, reparation,
herbicide, pesticide
Sundry inputs = insurance, hedging, interest
Overhead costs = capital, equipment, replacement,
maintenance
Sources:
1. Conv & NT: GrainSA 2021/22 online production accounts
2. RA: ASSET Research in-field trials 2021/22
Cost comparisons of various farming systems for the
Maluti area for the 2032/33 season assuming NO price
increase of fertilizers in 2022.
External inputs = fertilizer, lime, fuel, reparation,
herbicide, pesticide
Sundry inputs = insurance, hedging, interest
Overhead costs = capital, equipment, replacement,
maintenance
Source:
1. Model values:
https://sagrainmag.co.za/2022/05/03/financial-benefits-of-
converting-to-ca/
Cost comparisons of various farming systems for the
Maluti area for the 2032/33 season assuming a once-off
200% price increase of fertilizers in 2022.
Source:
1. Model values as per the previous, but added a once-off
shock to fertilizer prices of 200%
Grain SA. Money matters and financial services, Mini focus. 5 May 2020. Financial benefits of converting to
CA/RA. Available online: https://sagrainmag.co.za/2022/05/03/financial-benefits-of-converting-to-ca/
Grain SA. Money matters and financial services, Mini focus. 5 May 2020. Financial benefits
of converting to CA/RA. Available online: https://sagrainmag.co.za/2022/05/03/financial-
benefits-of-converting-to-ca/
Research results: CA adoption
Critical steps to CA adoption:
1. Improve your knowledge about the system, and plan for
the change to permanent CA at least 1 year in advance.
2. Analyse your soil (aim for a balanced nutrient and pH
status).
3. Avoid poor soils.
4. Level the soil surface.
5. Eliminate soil compaction and acidity problems before
starting CA.
6. Produce the largest possible amount of mulch cover
(summer cover crops).
7. Buy a no-till planter and sprayer.
8. Start on 10 % of your farm.
9. Use crop rotations , cover crops and livestock integration.
10. Be prepared to learn and adapt constantly –join the local
CA club, or form one.
What practices are followed by grain farmers in SA?
What factors played a role in CA adoption in South Africa?
(FAO, 2021)
Local pioneer CA farmers
Local farmer groups & research teams working with them
Local CA equipment manufacturers (‘selling the CA system’
with equipment)
International success stories and cross-visits (e.g., to and
from Argentina, Australia),
International pioneer CA farmers (and youtube!) (e.g., Gabe
Brown)
International CA scientist (and youtube!) (e.g., Elain
Ingham, Ray Archuleta, Allan Savory, Jonathan Lundgren),
Local CA scientist,
Although limited, in some cases there are appropriate
support to semi-commercial and smallholder farmers,
Local service providers and agribusiness (e.g., seed
companies).
Local awareness and information through farmers days,
conferences, webinars, popular agricultural magazines and
TV channels
Resource material
For CA-FIP information: https://assetresearch.org.za/
conservation-agriculture/
https://restory.co.za/relevant-media/
(many links in the excel)
https://www.youtube.com/channel/UCGb27IWUbLmYEhYL7
xf7cmg
https://www.youtube.com/channel/UC-
rnKyECFVKuLDgMkHedWZg
https://www.regenagsa.org.za/;https://www.youtube.com/c
hannel/UCCqTpf-5tTztBgxuqgW7tBg/featured
Numerous articles in SA Grain, Landbouweekblad, Farmers
Weekly, etc.
Scientific publications:
Smith, H.J., Trytsman, G., Nel, A.A., Strauss J.A., Kruger, E.,
Mampholo, R.K., Van
Coller, J.N., Otto, H., Steyn, J.G., Dreyer, I.D., Slabbert, D.,
Findlay, R., Zunckel, E. and Visser, L. 2021. From theory to
practice – key lessons in the adoption of Conservation
Agriculture in South Africa. In Kassam, A. (ed.). Advances in
Conservation Agriculture
Volume 3: Adoption and Spread. Cambridge: Burleigh
Dodds Science Publishing.
Smith, H.J., Kruger, E., Knot, J. and Blignaut, J.N. 2017.
Chapter 12: Conservation Agriculture in South Africa:
lessons from case studies. In Kassam, A., Mkomwa, S. and
Friedrich, T. (eds). Conservation agriculture for Africa:
building resilient farming systems in a changing climate.
Wallingford: CAB International.
Smith, H.J., Kruger, E., Knot, J. and Blignaut, J. 2017.
Conservation agriculture in South Africa: lessons from case
studies. In Kassam, A., Mkomwa, S. and Friedrich, T. (eds).
Conservation agriculture for Africa: building resilient
farming systems in a changing climate. Wallingford: CAB
International.
Strauss , J.A., Swanepoel, P.A., Smith, H.J. and Smit, E.H.
2021. A history of conservation agriculture in South Africa.
South African Journal of Plant and Soil. DOI:
0.1080/02571862.2021.1979112.
Strauss, J.A., Swanepoel, P.A., Laker, M.C. and Smith, H.J.
2021. Conservation agriculture in rainfed annual crop
production in South Africa. South African Journal of Plant
and Soil. DOI: 10.1080/02571862.2021.1891472.
Kruger, E., Smith, H.J., Ngcobo, P., Dlamini, M. and
Mathebula, T. 2021. CA innovation systems build climate
resilience for smallholder farmers in South Africa. In
Conservation Agriculture in Africa: Climate Smart
Agricultural Development. CABI.
Smith, H.J., Trytsman, G. and Nel, A.A. 2021. On-farm
experimentation for scaling-out conservation agriculture
using an innovation system approach in the North West
Province, South Africa. In Conservation Agriculture in
Africa: Climate Smart Agricultural Development. CABI.
Goddard, T., Basch, G., Derpsch, R., Hongwen, L., Jin, H.,
Karabayev, M., Kassam, A., Moriya, K., Peiretti, R. and
Smith, H.J. 2020. Institutional and policy support for
Conservation Agriculture uptake In Kassam, A. (ed.).
Advances in Conservation Agriculture Volume 1: Systems
and Science. Cambridge: Burleigh Dodds Science
Publishing.
Blignaut, J.N., de Wit, M., Knot, J., Smith, H., Nkambule, N.,
Drimie, S. and Midgley, S. 2015. Promoting and advancing
the uptake of sustainable, regenerative, conservation
agriculture in the maize production sector. Pretoria:
Development Bank of Southern Africa, Green economy
policy brief series.
Truter, W., Dannhauser, C., Smith, H.J. and Trytsman, G.
2017. Conservation agriculture: Integrated crop and
pasture-based livestock production systems. Article series,
SA Grain magazine. [https://www.grainsa.co.za/sa-graan-
grain-article-series/conservation-agriculture]
Haarhoff,S.J. and Swanepoel, P.A. 2020. Narrow rows and a
high maize plant population
improve water use and grain yield under conservation
agriculture. Agronomy Journal 112, 921–931.
Haarhoff, S.J. and Swanepoel, P.A. 2020. Geil mielieplante te
danke aan sterk wortelgroei. Arena Mei/Junie, 29–32.