ca experiences undera-commercialfarmingsetupatkunatsaestate-aug14 2
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CONSERVATION AGRICULTURE (CA) EXPERIENCES
UNDER A COMMERCIAL FARMING SETUP AT
KUNATSA ESTATE, ZIMBABWE.- PRODUCTION COSTS, PROBLEM WEEDS AND
CHALLENGES.
(23 May 2015)
Shingirai M Masvaure, Bundura University of Science Education
(Agribusiness Development)
Principles of Conservation Agriculture
Conservation agriculture (CA) is a crop management system based on three principles:
minimum soil movement (no soil inversion by tillage)
soil surface cover with crop residues and/or living plants
crop rotations to avoid pest and diseases,
CA Kunatsa Estate Experiences
As a concept of sustainable agricultural production CA requires less usage of chemical fertilisers, agro-chemicals, fossil fuels, and human labour whilst achieving improved crop yields.
Kunatsa Estate pioneered CA in Zimbabwe, in the 1980's.
By 1988/89 season the entire arable area was under CA tillage. Crop yields dramatically improved and stabilised, and the process of soil degradation was reversed.
Maize yields in excess of 10 tonnes per ha have been achieved with zero tillage. Farm average crop yields (tonnes/ha) are: maize, 8.1; soyabeans, 3.4; and wheat, 6.2.
Currently CA is practiced in one form or another in all 535 ha of arable land.
CA Kunatsa Estate Experiences
The positive environmental benefits of conservation agriculture include:
1. Improvement in water conservation: improves water infiltration, (raises water table and reduces the amount water required for irrigation).
2. Reduced soil erosion: protects the land from heavy rain, reduces water runoff. (allowing for 30–60 per cent greater rainfall infiltration).
3. Increased soil fertility and organic matter: help fix carbon so that CA reduces carbon dioxide emissions far more than conventional techniques.
4. Therefore CA practices acts as a carbon-sink against carbon emission.
CA Kunatsa Estate Experiences
The potential negative problems of CA in the transition years:
Difficulties in crop residue management,
Increased weeds and disease infestations that may require increased herbicide and pesticides use,
However, the judicious use of crop rotations, cover crops, some soil disturbances may help reduce the agronomic risks.
Satellite image of Kunatsa Estate
Advantages & disadvantages of various tillage systems
Ploughing Suited for poorly
drained soils.
Excellent
incorporation of
fertilisers and
pesticides.
Nearly complete
burial of weed seeds
and residues.
Well tilled seedbed.
Secondary tillage
required.
Major soil erosion
due to soil
pulverisation.
Vulnerable to erosion
on steeper slopes.
Surface residue not
available to protect
soil.
High soil moisture
loss.
Timeliness
consideration.
High fuel and labour
costs.
Advantages & disadvantages of various tillage systems
Chisel Ploughing Less winter wind erosion
from roughened surface.
Well adapted to poorly
drained soils.
Needed to break soil
compaction pans.
Good incorporation generally
leaves 50 to70% of the
existing maize residues on
the surface.
Little erosion control.
High soil moisture loss.
Shredding may be needed for
residue flow.
Medium fuel and labour
requirements.
Normally followed by one or
more secondary tillage
operations.
Advantages & disadvantages of various tillage systems
Disking Less erosion with more
residues.
Well adapted for well-drained
soils.
Good incorporation.
About 40 to 70% of residue
remains on surface following
maize or wheat residue.
Little erosion control with
more operations.
In fragile soyabean residue
does not leave enough
residue for substantial
erosion control.
High soil moisture loss.
Destroys soil structure.
Compacts wet soil.
Advantages & disadvantages of various tillage systems
No-Till Excellent erosion control.
Soil moisture conservation.
Minimum fuel and labour
costs.
Builds soil structure and
health.
Suited for many soil types.
Uniformly spread residue
increases water infiltration
and reduces soil moisture
evaporation.
No incorporation.
Increased dependence on
herbicides for pre and post-
emergence weed control.
Slow soil warming on poorly
drained soils.
Kunatsa Estate tillage systems for maize
1. Planting maize: Following barleyharvesting; ripper followed by zero tillplanning.
2. Early crop establishment of of maizeplanted with zero till planter.
3. Established maize crop: Followingbarley harvesting and zero tioll planteralong ripped lines.
Harvesting soyabeans and tillage methods
1. Harvesting soya bean. 2. Conventional tilled
soya bean following
potatoes
3. No till soya beans
following barley/wheat.
Reduced tillage (disking & barley planting) following harvesting a maize crop
7. 8. 9.
Germinating, early growth and fully established
barley following maize10. 11. 12.
Tillage Systems Cost ComparisonsActivity Application rate per ha Maize-No Till
Planter (JD2109)
Maize-Planter+ Ripper
Maize-Planter+ Disc
Maize-HandPlanting
Soya-No TillPlanter(JD2109)
Soya– Seed-drill (JDN750)
Irrigation 24 mm 6.17 6.17 6.17 8.89 6.17 6.17
Electricity 34 kWh 4.83 4.83 4.83 4.83 4.83 4.83
Ripper 30 l diesel - 41.44 - 41.44 - -
Roller 15 l diesel - 20.81 - 20.81 - -
Disc 30 l diesel - - 41.03 - - 41.03
Station Marker 10 l diesel - - - 14.91 - -
No Till planter 20 l diesel 28.22 - - - 28.22 -
Maize planter 20 l diesel - 27.88 27.88 - - -
Seed-drill 20 l diesel - - - - - 27.88
Hand Fertilisation 5.13 labour days - - - 11.81 - -
Hand Planting 10 labour days - - - 23.00 - -
Herbicide 2 Applications 14.60 14.60 14.60 14.60 14.60 14.60
Dual 1.5 l/ha 21.34 21.34 21.34 21.34 21.34 21.34
Round-up 2.0 l/ha 14.00 14.00 - 14.00 - 14.00
Atrazine 3.5 l/ha 28.00 28.00 28.00 28.00 - -
Karate 0.2 l/ha 2.00 2.00 2.00 2.00 2.00 2.00
Sencor 1.3 l/ha - - - - 31.20 31.20
Agil 1.0 l/ha - - - - 24.00 24.00
Classic 0.035 kg/ha - - - - 5.95 5.95
Wetter 0.25 l/ha - - - - 1.75 1.75
Totals Cost 119.16 181.07 145.85 205.63 140.06 194.75
Differences(USD) - 61.91 26.69 86.47 - 54.69
Tillage Cost Comparisons
The tabled data show that:
Zero or No-Till has the least costs; USD 119.16 and USD 140.06 per ha for both maize and soya beans, respectively.
Maize tillage practices that involves ripping, rolling and machine planting (USD 181.07/ha), and hand planting (USD 205.63/ha) are the more expensive.
Planting maize in disked lands is USD 35.22/ha cheaper than ripping and rolling:
In soyabeans Zero-tillage is USD 54.69/ha less expensive than disking and planting with a seed drill.
In both maize and soyabeans, zero tillage and ripping tend to result in better soil moisture retention, as the crops do not suffer moisture stress as in disked lands.
Fuel and Labour Requirements
The fuel and labour requirements for tillage varies greatly depending on the operations conducted, tillage implement, operating depth, operating speed, soil conditions, and many other variables.
Some studies have shown that the plough, chisel plough and disk to are 3.9, 2.5 and 2 times higher fuel requirements than in no-tillage system, respectively.
Similarly labour requirements per hectare for the plough, chisel plough and disc are 2.7, 2.0 and 1.6 times greater than in no-till, respectively.
Labour savings allow a larger area to be farmed without additional equipment or help, or more-timely planting may result in greater yields.
In addition, costs for tractors, tillage equipment, and maintenance will be less with fewer tillage operations.
Problem weed (milk weed) in soyabeans
1. 2. 3
Problem weed (Wandering Jew) in soyabeans
4. 5.
Problem weed (Sub-morning glory) in maize and soyabeans
16. 17.
Problem weed () in soyabean
13. 14.
Problem grasses in soyabean, wheat or barley
1. Tough annual grass in
soya bean.
2. Fox tail in wheat 3. Rye grass in wheat
Conclusions
Managing weeds in CA systems requires a planned approach. Anticipating potential problems, find timely solutions, and make use of integrated pest management techniques (IPM), such as field scouting and crop rotation, are key to successful CA management strategies.
Several factors make weed management in CA unique. In reduced-tillage agriculture, growing vegetation (e.g. volunteer wheat, barley or early weeds) may already be present at planting time and must be killed or suppressed.
If weed pressure or plant residue is intense, an adjustment in herbicide rate or alternative control strategies may be required.
Occasional selective tillage may be necessary to keep problem weeds in line. Finally, other management techniques, such as crop rotation, are critical.
Conclusions
Carefully evaluate the need for each tillage operation and pesticide application.
Systems with more than two tillage operations prior to planting need careful examination. Additional operations are often unnecessary and only increase soil losses, compaction and production costs.
Do not shred standing residue prior to planting. Planters, drills, and cultivators perform better when residue is standing and attached to the soil, rather than unattached and lying flat.
THANK YOU FOR YOUR TIME
Many thanks go Directors of Kunatsa Estate, which is the source of most of the slides in this presentation.