Harvesting forage is more difficult than harvesting grain crops. When first harvested, the forage crop has a high bulk and mass, holding 70-80 percent water. It must be dried to a safe moisture level of around 20 to 25% for storage, either naturally or artificially. The economic feasibility of mechanizing the harvesting process of fodder crops is limited due to the low product value. The mowers cut the crop and windrow on the field, which is then gathered manually for further chopping.
The field forage harvester is a combination of a plant-cutting unit and a chopping unit that harvests forage. Because it severs the standing stalks from the ground and chops them into silage in one continuous operation in the field, the field forage harvester serves as both a row binder and a silage cutter. Field choppers and flail harvesters can be divided into two categories based on the mechanism used to cut the produce.
A mower is a machine that is mostly used to harvest grasses and fodder crops. It makes hay by cutting the stems of standing plants. The mower cutter bar may cut the stems at a height of 3-10 cm above the ground. Various types of mowers are used to cut grass and forage crops, including cylinder, reciprocating, horizontal rotary, and flail mowers. Mowers are categorized as manually driven, animal-drawn, tractor-drawn, or self-propelled depending on the source of power. Mowers are categorised as trailed, semi-mounted, or fully mounted depending on how they are hitched. Mowers that are semi-mounted or integrally mounted can be classed as rear, mid, or front-mounted. Mowers are classed as ground-driven, engine-driven, or PTO-driven depending on the kind of drive employed. The following are the essential components of a traditional animal-drawn mower:
- To cut the crop and separate it from the uncut area, a cutter bar is used.
- To receive and transfer motion force, a power transmission unit is used.
- Moving pieces are supported by a frame.
- Wheels for transportation and operation of the cutting mechanism, as well as
- Auxiliary components for lifting and lowering the cutting bar.
Classification of Mowers
The mowers on the basis of their cutting mechanism are classified as:
a) Finger-type cutter bar mower
The active knife presses the plant against the fixed ledger-plate of the finger guard, shearing it.
b) Under-knife mower
This category includes a double knife cutter bar with one knife fixed. With this method, one knife serves as the guard’s ledger plate, while the other serves as a regular reciprocating knife. These mowers have a basic design that reduces the risks of being blocked by dense vegetation or minor soil objects. They are not, however, appropriate for stony areas.
c) Double cutter-bar mower
It comes with two cutter bars that work in opposing directions. Instead of the ledger plate of protection, the plants are sheared by the two active blades. Such mowers have the benefits of low power consumption, clean cuts, faster operation, cutting close to the ground, and so on. The finger spacing of cutter-bar mowers is used to further categorize them.
(i) Normal cutter-bar: The space between guard fingers and knife portions in these mowers is set at 76.2 mm. These mowers are best for crops with thick stems, such as jowar, maize, and bajra.
(ii) Medium fine cutter-bar: The finger spacing is lowered from 76.2 mm to 50.00 mm in this type of cutter-bar, but the knife spacing remains unchanged at 76.2 mm. In dense crops, this process aids better cutting.
(iii) Fine cutter-bar: Finger spicing is preserved at 38.1 mm, while knife spacing is kept at 76.2 mm. This device is ideal for harvesting fine stemmed plants on broken ground in grasslands.
A conditioning attachment is included with the reciprocating mower to perform cutting and conditioning operations. Mower-cum-crushers are the name for such mowers.
(e) Disc mowers
Plants are chopped by a rotating blade in a horizontal plane installed on spherical discs in these devices. These mowers are further classed based on their construction:
(i) Drum Disc Mower: These mowers use drum type discs, which means that a drum is installed over the disc to allow the chopped material to push back into the swath.
(ii) Rafter-disc Mower: These mowers are identical to drum disc mowers, except that (a) the power to the disc is delivered by a system positioned below the disc, and (b) the cut material is pushed back by spinning discs rather than drums as in the previous instance. Throw-away bits are included with the discs to assist in pushing the chopped material back.
It comprises of a single horizontal high-speed cutting element (60-70 m/s) that principally depends on the material’s inertia to provide the opposing force necessary for shear. One of the shearing factors is also the ground. It operates on the free-cutting concept. The plant gets sheared and transported with the blade when a rotating blade strikes it. The normal component of the force cuts the stalk, while the tangential component assists in imparting kinetic momentum to the plant, allowing it to follow the blade for a short distance. The component of forward velocity also contributes to the magnitude of both of the four components.
There are two types of rotary mowers: The Disc-type mower and the Rotary stalk-cutter and shredder are two types of mowers. The disc type mower is equipped with 2-3 swinging blades measuring 75 mm x 40 mm x 3 mm in size. The number of discs and their diameter are determined by the swath width. The blade moves in a cycloid pattern due to the disc’s rotating speed and the tractor’s forward speed. Because the tangential component of the force is significantly greater than the radial component, the material is sliced rather than transported away from the cut region. To send the cut material backwards, throw-away bits are supplied on the cylinder and/or on the discs. Two swinging knives rotate on a horizontal plane and are housed in the rotary cutter and shredder. By impact and shear force, the revolving blades cut the material. Because of the kinetic energy given by the cutting blade, the material is transported to the discharge end.
The flail mower chops the plants into short feed lengths and blows the chopped and cut debris into the accompanying trailer. These devices are used to harvest crops for daily consumption or silage production. By raising or lowering the space between the shear-bar and the flail-tip, the chopped lengths of the stalks may be changed from fine-medium to coarse. The forge conditioning necessary to accelerate the drying rate during the hay producing process may also be done using the aforementioned machine.
Cylinder Type Mower: It is generally used for lawn mowing. It includes lawn mowers and gang mowers. It could be hand-propelled and self-propelled lawn mowers and tractor-drawn and tractor-mounted gang mowers. It has rotating helical blades arranged in horizontal plane (Figs. 1 & 2). There are three gangs in this mower having 3-4 helical blades each supported over vertical discs. The rotors of this type of mowers are supported on ball bearings at each end. With the rotation of blades, forage or grasses are cut for example lawn mower. It can cover about 1.5-2.0 ha/h at a speed of 8-10 km/h.
Fig. 1: cylinder mower.
Rotating Disc-type Mowers: Disc mowers are divided into two categories. On the perimeter of one kind are discs to which free-swinging blades (2-4 in number) are affixed. The revolving knives are often placed on bearings on a cutting bar similar to those of a reciprocating mower. Due to the fact that this sort of mower cuts by impact, the energy needs are rather minimal. There are normally two large-diameter moving drums in drum-type mowers. This is powered by a belt and pulley system. Each disc has three to four steel blades that rotate at a speed of around 2000 rpm. The diameter of the disc varies between 60 and 80 cm. Cutting occurs due to impact in this one as well. These mowers cut pretty wide swaths, and the gathered material dries quickly. The operation is generally relatively smooth and power consumption is low due to the lack of gear or chain drive.
Fig. 2: gang mower.
Adjustments of mower reaper
|1.||Reel||i) Does not rotate
ii)Improper gathering of crop
|i) Check tension of reel belt. Reel by hand to ensure that the drive pulley key and belt are secured.
ii) Adjust height according to height of crop
|2.||Cutter bar||Unsatisfactory cutting||i) Reduce forward speed
ii) Correct the registration
iii) Sharpen the knife sections or replace if worn out.
iv) Check drive belt tension. If loose, tighten
Farmers in some locations have discovered that cutting and windrowing the top half of the plants with the grain attached allows for early harvesting and better grain protection given the following conditions.
When the grain ripens unevenly.
(ii) When the fields are overgrown.
(iii) When the harvest is mature but the straw is still green.
(iv) When the grain has a high moisture content.
(v) When agricultural circumstances are such that legume crops, if allowed until mature, tend to shatter, and
(vi) When the weather prevents direct merging. A power-takeoff-driven knife, platform canvas, and reel make up the windrowing machine.
The grain heads are chopped off and fall onto the canvas of the travelling platform, which transports the grain over one end to the stubble. The grain is usually delivered over the end farthest away from the standing grain on most windrowing machines. Machines for centre delivery are available.
There are two types of headers on self-propelled windrowers. On hay machines, the augur cross feed is the most prevalent, but it’s too forceful for grain. The draper kind of windrower is used on both grain and hay windrowers. The greatest width that may be cut with a hay windrower is determined by the maximum size of windrow that can cure in a reasonable amount of time. In irrigated locations, windrowers with cutting widths of 3.65 m and 4.25 m are common, with hay yields per cutting ranging from 2.2 to 3.4 Mg of dry matter per hectare. Knife speeds are similar to those seen on mower-conditioners, although stroke lengths are frequently 6 to 10 mm longer than the 76.2 mm guard spacing. Knife parts with chrome plating are generally widely utilized. Conditioning attachments are typically 0.9 to 1.4 m wide, however some 2.75 m self-propelled machines have used the direct-feed, full-width-conditioner method of pull-type mower-conditioners.
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