There are two types of cultivation broadly used in crop production. The first is called PRIMARY CULTIVATION. This is where, if the operation is carried out correctly, the soil is deeply disturbed and inverted so that soil from lower levels is exposed to the surface. Thus digging is a form of primary cultivation, as is PLOUGHING. The end result should be a surface which while overall being as even as possible, should expose the MAXIMUM surface area to weathering. Primary cultivation is usually carried out in the AUTUMN/WINTER period, so that the soil is weathered down by frost over the winter period. Following PRIMARY cultivation is SECONDARY CULTIVATION. This is where the ploughed or dug soil is worked down to a physical condition whereor planting is possible. This is called planting or sowing TILTH. Tilth can be said to be the physical condition of the soil in terms of its suitability for cultivation, as a or planting bed, and its effect on penetration and emergence.
PRIMARY CULTIVATION equipment ranges from the SPADE to the PLOUGH. While a spade is an essential item of horticultural equipment, used for many other purposes than cultivation, the plough is not widely used on a small unspecialised scale. However, it is possible to get plough attachments to standard rotary cultivators, which while they will only do one furrow at a time, can be useful to reduce the donkey work involved in primary cultivation.
SECONDARY CULTIVATION is breaking the soil down to a suitable TILTH to enable sowing or planting to take place. The simplest tool to use for this is the RAKE, a common piece of gardening equipment. On a larger scale such items as HARROWS are used. DISC HARROWS, or CHAIN HARROWS are the commonest types in use.
Primary and secondary cultivation are very important tools in the efficient management of the soil both~on a large and a small scale.
ROTARY CULTIVATORS are often used on both small and large scales, by professional and amateur alike. Quite often these are used to carry out primary and secondary cultivation in one operation. The overall effect is not to INVERT the top layers of soil, but to mix the top soil as it is thrashed by the rotors. The slower the action the less the severity of the crushing and compressing of the clods. There are two adverse effects:-
i) On the soil structure – the natural structure cohesion tends to be lost to a mechanically produced tilth particularly serious for clay and silty clay soils if plastic (with moisture).
ii) The effect on the soil just below the blades – which tends to become compressed and the impacted surface somewhat ‘glazed’ – creating a ‘rotovator pan’ – poor forto penetrate, poor for , poor for aeration and very persistent on heavy soils.
The types of tines used has a bearing and some of those which rotate more slowly are much kinder; similarly the spring tine types (if still available) are much more favourable to the soil structure.
Blades can be powered by either electric motor, or petrol engine. Larger professional models are often powered by diesel engine. Whatever the method of powering the rotor and hence the blades, the engine or power unit must also power wheels so that the machine can move forward.
N.B. Some tillers are propelled by the rotor action.
The rotary cultivator (also called a ROTOVATOR) usually produces a fine tilth directly which is suitable for planting after a final raking or light harrowing. Thus it is a quicker way of producing a fine tilth than by ploughing. There can be problems however with rotary cultivation on the same ground at the same depth over a long period, as a compacted layer can
develop at the CULTIVATION DEPTH: SEE PREVIOUS DRAWING. This can also happen with ploughing where the plough share can smear and compact the layer of soil directly beneath it; OVER USE, and CONTINUOUS USE OF ROTARY CULTIVATORS CAN SERIOUSLY DAMAGE SOIL STRUCTURE. They need using with care, and under the right conditions.
USES OF THE ROTARY CULTIVATOR
1. Widely used in the landscape industry for land preparation before sowing grass seed and planting trees and shrubs.
It can be used as a sort of mechanical hoe to control weeds both in open ground and in between crop rows. Here the machine is set high so that only the top 50 – 75 mm (2 – 3 inch) of soil are disturbed.
Can be used to chop up remains of vegetation on the surface of the ground before sowing or planting.
The fineness of TILTH which the rotary cultivator produces can be controlled by the following three factors:
1. Theof the shield and adjustable hood .
If the shield and hood are RAISED, then the tilth produced will be COARSE. If lowered, then the tilth will be fine.
2. CONDITION OF THE SOIL. The moisture content of the soil is all important. If too wet, then the soil will not break down into crumbs, but will be sliced into large unmanageable lumps. The correct moisture content to ensure that the use of the cultivator produces a satisfactory tilth with the minimum soil damage, is when the soil clods readily break down to smaller particles when disturbed.
3. FORWARD SPEED OF THE MACHINE. The faster the forward speed the finer the tilth because there will be more cuts per metre. Conversely, the slower the speed, the coarser the tilth because there are fewer cuts per metre.
The cultivation width of a rotary cultivator obviously varies with the size of the machine. Small pedestrian operated machines offer widths in the range of 300mm (1) up to 750mm (2 ½ inch). Much larger machines are available which can be attached to the rear of a tractor and powered from the tractor engine via the power takeoff at the rear.
OUTLINE OF MAINTENANCE OF THE ROTARY CULTIVATOR
1. The engine should be maintained exactly to the manufacturer..’s.instruction handbook.
2. The oil-level should be topped up in the chaincase and gearbox if necessary; the oil level in these two should be regularly checked if the machine is regularly used.
3. Before use, the bolts which hold the blades on to the rotor shaft should be checked to ensure that they are tight.
4. The instruction book should be consulted to see where the oil and grease points are, and this should be done before use.
Some rotary cultivators are available with a range of attachments which include ploughs, lawn aerators, and tines of various shapes which can be used as cultivators and hoes.
Always follow the manufacturer’s instructions carefully.
Wear STEEL TOE-CAPPED boots wherever possible.
Do not re-fuel the engine when running, or when hot; switch off and allow to cool.
Never attempt any sort of maintenance when the rotors are working.
Make sure that the rotors are in neutral when moving machine over solid ground.
Keep well clear of rotors when the machine is working.
Any mechanical equipment used in the garden should be maintained with the same care as that outlined for the rotary cultivator. Greasing and oiling moving parts are especially important, and this means following manufacturer’s instructions, and using the correct oils and greases. Equipment such as hedgecutters need special attention to greasing and blade cleaning.
Any electrical equipment is best used with a circuit breaker plugged into the power socket, and the equipment plugged into this; this will act as a safety measure should any problem with the machine arise when in use, or if the cable becomes damaged. When using any type of electrical equipment, ALWAYS work forward with the cable behind. NEVER work back over the cable. This-seems- like common sense, but mistakes are easily made when actually… doing the job. With things such as hedgecutters, the cable is best looped over the shoulders via the waist, always working forwards with the cable behind to reduce the chance ofthrough the cable. Alternatively, a knot can be tied in the cable to form a loop, with enough spare cable next to the cutter so that it can be manoeuvred effectively. The loop of cable is then placed over the shoulder. Always be careful not to get tangled up in the cable. Similarly when electrically powered lawn mowers are being used, the cable should be looped over the shoulder via the waist, working with the cable behind to ensure that it does not come to any damage.
A NOTE ON SAFETY WHEN USING ROTARY MOWERS AND STRIMMERS
Any machinery in the garden can be dangerous if not used properly. ROTARY MOWERS can be especially- dangerous. Following a few simple rules will reduce the chance of accidents. When using rotary mowers and strimmers, use suitable footwear; I.e. steel toe-capped boots or shoes.
Adjust and maintain machine to the manufacturer’s recommendations. If there are any shields on the mower, make sure that these are in place, and adjusted properly.
Check area to be mown for stones, and remove before starting; this also prevents damage to the mower itself.
Use goggles or safety glasses when using strimmers.
Work FORWARDS pushing the mower, avoid pulling the mower towards you.
Keep hands and feet well away from the cutter when the motor is running.
The mower should never be left with the motor running.
Before any adjustments are made on the mower, the engine should be stopped, and the spark plug lead removed from the spark plug.
Be aware of people in the vicinity when mowing or strimming, because of the risk of flying debris.
OTHER IMPORTANT POINTS WHEN USING ELECTRICAL EQUIPMENT
NEVER attempt repairs or rewiring before the equipment is switched off and unplugged. If the equipment is static, then switch off, and remove the fuse which is connected to that particular circuit.
In the case of electric shock, do not touch the person until the power has been switched off. If for some reason this cannot be done, the person should be pushed away with a piece of material which does not conduct electricity, such as a length of dry wood. Medical attention should be called for immediately: artificial respiration may be needed.