Tractor drawn cultivator can be of two types: 1. Trailed Cultivator 2. Mounted Cultivator.
Type # 1. Trailed Cultivator:
It consists of a main frame which carries a number of cross members to which tines are fitted. At the forward end of the cultivator, there is a hitch arrangement for hitching purpose. A pair of wheels is provided in the cultivator. The lift is operated by both wheels simultaneously so that draft remains even and uniform.
The height of the hitch is adjusted so that main frame remains horizontal over a range of depth setting. The tines in each row are spaced widely to allow free passage of the soil and trash around them. The tines in subsequent rows are staggered so that the implement calls cover the entire width nicely.
The depth of working is set roughly by adjusting the tine in their clamps and the final depth control is done by a screw lever. Usually the tines are damaged due to turning the implement at the headland without lifting it up. Care should be taken to lift the tines off the ground before turning.
Type # 2. Mounted Cultivator:
Tractors fitted with hydraulic lift operate the mounted type cultivators. A rectangular frame of angle iron is mounted on three point hydraulic linkage of the tractor. The cross members carry the tines in two staggered lines. For actual cutting the soil, different types of shovels and sweeps are used.
A few important shovels and sweeps are:
(a) Single point shovel
(b) Double point shovel
(c) Spear head shovel
(d) Sweep
(e) Half sweep
(f) Furrower
Depending upon the type of soil and crop, shovels are chosen for use on the cultivators.
Usually tractor drawn cultivators are of two types, depending upon the flexibility and rigidity of tines:
(a) Cultivator with Spring Loaded Tines
(b) Cultivator with Rigid Tines
(a) Cultivator with Spring Loaded Tines:
A tine hinged to the frame and loaded with a spring so that it swings back when an obstacle is encountered, is called spring loaded tine. Each of the tines of this type of cultivator is provided with two heavy coil springs, pre- tensioned to ensure minimum movement except when an obstacle is encountered. The springs operate, when the points strike roots or large stones by allowing the tines to ride over the obstruction, thus preventing damage.
On passing over the obstruction, the tines are automatically reset and work continues without interruption. The tines are made of high carbon steel and are held in proper alignment on the main frame members.
This type of cultivator is particularly recommended for soils which are embedded with stones or stumps. A pair of gauge wheel is provided on the cultivator for controlling the depth of operation. The cultivator may be fitted with 7, 9, 11, 13 tines or more depending upon the requirements.
(b) Cultivator with Rigid Tines:
Rigid tines of the cultivator are those tines which do not deflect dining the work in the field. The tines are bolted between angle braces, fastened to the main bars by sturdy clamps and bolts. Spacing of the tines is changed simply by slackening the bolts and sliding the braces to the desired position.
Since rigid tines are mounted on the front and rear tool bars, the spacing between the tines can be easily adjusted without getting the tines choked with stubbles of the previous crop or weed growth. A pair of gauge wheel is used for controlling the depth of operation.
Duck Foot Cultivator:
It is a type of rigid cultivator which is used mostly for shallow ploughing, destruction of weeds and retention of moisture. It consists of steel frame and rigid tines to which sweeps are attached. The implement is attached to the tractor with three point hitch system and is controlled by hydraulic system. The sweeps are fabricated from high carbon steel. Number of sweeps can be reduced according to requirement. Usually this cultivator is about 225 cm long, 60 cm wide with 7 sweeps.
2. Animal Drawn Cultivator:
Depending upon local conditions, soil and climate, different types of cultivators have been designed and are being used extensively throughout the country. Three tined cultivators with seeding attachment are popular in some part of the country.
Three Tyned Cultivators with Seeding Attachment:
It is a common implement used in the country. It is used for secondary tillage operations. It is also used for interculture of row crops by detaching the seeding attachment. It is also used for sowing crops in three rows. The rate of seed dropping is manually controlled.
The main parts of the cultivator are:
1. Frame
2. Seeding Attachment
3. Shovel
4. Tine
5. Beam
6. Handle
1. Frame:
Frame is made of steel flat usually of size 40 x 10 mm. There is vertical hitch or clevis arrangement with the help of which animals of varying sizes can be hitched to the cultivator.
2. Seeding Attachment:
A seed funnel usually made of mild steel sheet of about 0.70 mm thickness is fixed to the handle. At the bottom of the funnel there are three openings at 120° to each other leading to the seed tubes. The diameter of the seed tube usually varies between 25 to 40 mm.
3. Shovel:
Shovel is usually of reversible type. The width of the shovel varies between 50 and 75 mm and is made of steel having carbon content ranging from 0.5 to 0.6%. The thickness of the shovel ranges between 3.15 to 4.50 mm. The cutting angle varies in the range of 15° to 20°. The shovels are fixed to the tines with suitable bolts.
4. Tine:
The tine is made of mild steel flat having carbon content ranging from 0.15 to 0.25%. A flat of usually 40 x 4 mm size is used for tines.
5. Beam:
It is made of hard wood and is suitably bolted to the frame.
6. Handle:
Handle is usually made of mild steel flat. The handle is bolted to the frame with a brace. The grip is made of wood or pipe.