Tractor, Plough and a Wet Field
A farmer has a 45 kW tractor and a three-furrow mouldboard plough. The field is 3 hectares of clay loam that received 60 mm of rain two days ago. The farmer wants to plough today so that planting can happen in three days. The tractor's rear tyres are worn and inflated to a low pressure. The plough's shares are blunt and one mouldboard is bent. The farmer also plans to transport 2 tonnes of fertilizer on a single-axle trailer with no lights along a public road at dusk. The nearest workshop is 40 km away and closes at 5 pm.
1. Should the farmer plough today? Give a reasoned recommendation.
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No. Ploughing clay loam two days after 60 mm of rain will cause smearing and compaction because the soil is too wet to shatter. The correct test is to squeeze a handful: if it forms a ribbon that does not crumble, it is too wet. Ploughing wet clay creates clods and a plough pan that will reduce rooting for the whole season. Waiting two or three more days until the soil crumbles is better than rushing. The farmer's planting date can shift slightly; yield loss from compaction is usually greater than loss from a few days' delay. If a small area must be prepared, plough only the driest part and avoid working the rest.
2. List the machinery faults and explain the consequence of each.
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Blunt shares increase draught, so the 45 kW tractor will struggle and use more fuel, and the soil will be poorly inverted. A bent mouldboard gives an uneven furrow and leaves unburied residue, which harbours pests and interferes with planting. Worn rear tyres reduce traction on wet clay, causing wheel slip; slip wastes fuel and power and can polish the soil surface. Low tyre pressure on a heavy load increases sidewall flexing and heat, risking damage. The combination means the job will be slow and poorly done. The plough should be repaired before use, and the tyres replaced or at least inflated correctly for the load.
3. Assess the road transport plan and state what must change.
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The plan is unsafe and likely illegal. A single-axle trailer with no lights at dusk is a collision risk, and 2 tonnes may exceed the trailer's rated capacity and the tractor's braking ability. The load should be checked against the trailer plate, secured, and the journey made in daylight with lights and a reflective triangle. If the trailer has no lighting, it should not be used on a public road at dusk. The farmer should also check that the tractor's brakes can hold the load and that the route avoids steep descents. Safety and legal compliance take priority over convenience.