Session 5:
Minimum cultivation and the machinery used to achieve this.
Aim:
To show the purpose of minimum tillage and machinery used to achieve this.
Objectives
- Explain various cultivation systems.
- Recognise various machines used to prepare a seed-bed.
- Explain the advantages and disadvantages of minimum cultivation.
- Explain how work rate can be calculated.
Note
Before operation of any machine make sure you familiarise yourself with the following:
- Risk assessment
- Adherence to industry safety guidance and operator’s manual
- Safe start and stop
- Monitoring of machine performance and output
- Effective communications
- Clearance of blockages
- Conversion between work and transport positions
- Economic operation
- Safe and efficient operation
Three ways to prepare a seed-bed
- Conventional cultivation
- Minimum cultivation
- No tillage
- Minimum Tillage is a technique that reduces the degree of soil disruption.
- Crop residues are not ploughed under after harvest.
- Various machinery are involved in this process.
- Various machinery are involved in this process
Class exercise
Advantages
- Lower costs and energy inputs.
- Wear and tear on machinery.
- Improved soil structure and less risk of damage from machinery.
- Cuts soil erosion.
- Soil is able to retain moisture.
Class exercise
Disadvantages
- Dealing with crop residues.
- Costs of herbicides and their potential problems.
- Increases in disease associated with residues and reduced soil disturbance.
Minimum tillage in Malawi, Africa
World record for cultivation
643.8 hectares in 24 hours
Predicted work rate for a 6.5m cultivator
The formula to work out the work rate =
Predicted work rate for a 6.5m cultivator
Comparison of reduced cultivation verus ploughing.
Minimum Tillage
- To reduce energy consumption
- To reduce labour costs
- To conserve moisture
- To retain plant cover to minimize erosion
Advantages of minimal tillage
- lower costs and energy inputs
- less wear and tear on machinery
- improved soil structure and less risk of damage from machinery
- reduced soil erosion and runoff
- increased beneficial invertebrates and earthworms
- decreased mineralisation of nitrogen and reduced leaching risk
- labour costs have been reduced
- machinery running costs have been reduced
Next you need to consider what problems are likely to arise from any changes in tillage technology and how they might be overcome.
Amongst these might be:
- dealing with crop residues.
- increases in disease associated with residues and reduced soil disturbance and whether a changed crop sequence might be an option to overcome the problem.
- increases in pests until the system reaches an equilibrium between pests and predators.
- alternative ways of dealing with weeds and the costs of herbicides and their potential problems. It should always be recognized that any chemicals, though very useful in the short-term, may create problems of herbicide resistance in weeds if herbicide types are not rotated in the longer-term.
- establishment problems associated with poorer tilth of seed-beds.
The final issue to think about is that the trial must be long-term, possibly more than three years.
When moving from full tillage to zero-till, the micro-flora and fauna take a long time to re-establish themselves and reach equilibrium in a relatively undisturbed soil profile. This duration may discourage the farmer from starting the trial even though the potential benefits of reducing the level of tillage are well understood.
Opportunities to reduce environmental impact of working the land
The first question to answer with the farmer is why are you planning to do tillage trials? The design of the trial will depend on the answer.
Consider whether there are opportunities to:
- reduce erosion problems on the farm where there is steeply sloping land.
- get the crop in earlier, closer to the optimum window for the best variety, if tillage and seeding could be done more quickly. Would earlier planting lead to increased yield? Would this be an overall economic benefit to the farm? Work out approximate amounts.
- cut back tillage passes without loss in yield thus saving money by reducing fuel and implement wear and operator time on tillage activities. Calculate how much might be saved.
- reduce a common problem of soil compaction associated with continuous movement of heavy machinery over the land.
- minimize loss of scarce water stored during fallow by tilling and planting in one pass. Would this lead to increased yield by making more water available to the crop in the establishment phase? Estimate how much.
Summary
Now you can...