The aim of soil preparation is to create a seedbed into which seeds or plants can be transplanted
The purpose is to provide loose soil to an appropriate tilth for the seed sowing. Fine tilth requires more time and money and can lead to capping and potential soil erosion.
Primary cultivation is usually undertaken with a plough:
- Traditional –animal drawn wooden ploughs made from wood with a metal point. They open up the soil but do not turn or invert it
- Mouldboard plough –Can be animal drawn which are single furrow or tractor drawn which are multi-furrow
- Disc plough – Tractor drawn and multi disc. Similar action to a mouldboard plough, but chops the soil rather than inverts it completely. Copes with debris, stumps, roots and trash better than a mould board plough so better for the tropics. Need to be of sufficient weight to penetrate the soil.
- Chisel plough (ripper) – Can be animal or tractor drawn. A ridged tine is pulled through the soil. Can be used to break up the pan in the soil. (A pan is a layer of compacted soil that develops after a couple of years of ploughing)
These implements include tines, discs, rollers and levellers.
- Tined cultivators – can be pulled by animals or tractors. Implements consist of a framework carrying a number of tines which when pulled through soil break down clods and uproot small weeds
- Disc Harrows – disc harrows break down clods and mix surface debris. More expensive to purchase than a tined harrow
- Rotary cultivator – can be ground driven or run from a tractor PTO. A rotary cultivator is more expensive and difficult to maintain than tined or disc implements, but produces a finer tilth
- Ridgers and bed makers. These can be simple implements pulled by animal, or larger and tractor pulled
- Multipurpose toolbar – most implements are single purpose, but machines that multi task for example with tines, discs and rollers are increasingly common in use in theUK. Haven’t seen them in the tropics mind. Need high HP tractors to operate, but one pass implements use a lot less fuel and time
General negative impacts of increased mechanisation:
- Capital cost
- Loan interest
- Operating costs
- Availability of mechanics/skilled labour to operate machines
- Spare parts availability
- Increased requirement for on-going maintenance – greasing bearings, checking fluid levels etc
- Increase in unemployment although this is subject to debate
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Written by Fiona Johnson