The tractor
Speaking of farm machines, the tractor must necessarily be mentioned in the first place. Today one cannot imagine practically any agricultural work done without a tractor. This steel horse is always ready for the job, day and night in any weather. With ease and grace it cuts through hard soil, sand and snow, bogland and marshes. Having a mighty pulling power, a tractor can pass through any difficult ground.
No other vehicle is better adapted to haul and work all kinds of agricultural machinery and implements than a tractor. It is a machine usually powered with a gasoline or Diesel engine and is used to draw and work agricultural implements for ploughing, sowing, harvesting, mowing and a large variety of other jobs. A tractor is also used to cut roads, dig ditches and pits, uproot stumps, cut the bush, etc. The tractor can be wheel or caterpillar type. The former is more powerful. Versatile and economical as it is, the tractor finds in fact no end of useful applications in farming, not to speak of lumbering where skidding tractors are the best means of bringing cut timber from out of the forests. Tractors can be used both for stationary and field work. Many agricultural machines are tractor-propelled, that is to say there is a power take off (PTO) to the tractor-hauled implement; or else, the farming devices are tractor-borne. On virgin and long-fallow lands heavy tractors with breaker ploughs are essential.
Land reclamation on boglands, calling for drainage, requires heavy-type tractors to which bog-and-brush ploughs are attached. Of course, as other machines, the tractor is being constantly improved. One of the most recent types is the 53 PTO all purpose, four plough and four cultivator type with a 3-cylinder diesel engine, which is highly adapted to everyday jobs on every farm.
The bulldozer
Bulldozers are built to move earth, broken stone and other discrete materials over short distances, to level out patches of land, fill trenches, pits and ditches.
A bulldozer can be mounted either on a wheeled tractor or on a crawler tractor. The mouldboards of bulldozers are lifted and lowered by power jacks. The installation of the bulldozers does not involve any structural changes in the tractors which, after removal of the mounted equipment, may revert to their original use.
The mouldboard of a bulldozer is controlled, through a system of cables by a single-drum winch installed on the tractor.
These machines are simple in operation and servicing, and possess high efficiency and labour-saving characteristics.
The universal frame of these bulldozers allows the position of the mouldboard to be adjusted in various planes; besides, the frame may be fitted with other replaceable attachments such as grubbers, brush breakers and snow removers.
The combine
We shall now consider the most comprehensive and versatile machine: the combine. It has been very properly named “the Ship of the Fields”. This is indeed one of the agricultural machines that has most vastly, improved large-scale wheat farming especially in the Soviet Union. It is otherwise called the harvester combine or the header.
The combine is an agricultural machine – usually operated by one man – which cuts the corn, then threshes out the grain and winnows it. The cleaned grain is gathered m the bin of the combine and then taken away by lorries. The straw is returned to the field and made into bunches.
In front of the combine there is a table, which cuts down ''the stalks brought up to it by the reel, which then again feeds them onto the central part of the table while the transporter catches them up and sends them off to the threshing" unit. In the thresher the grain is threshed out of the stalks and next through the deck (mounted under the threshing cylinder) falls upon the bolter and thence passes to the screen.
The straw, in its turn is fed on to the straw-walker. Here it is shaken to remove the left-over grain while the straw itself is gathered on a straw-tacker. As to the grain, it is now freed from impurities by a current of air coming from the fan. Then it falls through the riddle and through the grain auger runs to the flight elevator, which finally conveys it to the bunker or bin. After the grain is discharged from the bin it passes over to the pocket separator which classes the grain for different purposes: as seed-stock, milling material, grist, etc. Thence it goes to the bin and finally to the elevator.
The combined harvester is mostly mounted on wheels provided with pneumatic tyres but it may also have caterpillar tread.
Specialized harvesters
No end of other specialized harvesters are in existence, each of them specially designed for the purpose intended. Thus, we find cotton harvesters, pea harvesters, tomato harvesters, and even cherry and orange harvesters.
For harvesting root and tuber crops there exist various diggers, such as potato diggers, carrot diggers, onion diggers, even up to special sweet-potato diggers. But perhaps the best labour-saving devices are tuber and root harvesting combines among which the potato harvester stands out with particular prominence. This machine is, as a rule, not self-propelled, but actuated by a PTO from a tractor. Its main components are the shares, a haulm remover or topper, a chain elevator, a clod breaker, a lifting drum covered with polyethylene wire and a sorting table. The shares simultaneously dig down two potato rows. The mass dug out passes to the chain elevator whereupon the clods are broken by the clod breaker and the tubers separated. At the same time the removed haulm is thrown aside on the field. The tubers, separated from the clods, now pass over to the lifting drum which feeds them onto the sorting table which separates the tubers from the remaining earth. Finally the clean potatoes are fed into a bin.
The crimper
It is widely admitted that hay crimping is a fast, efficient, short cut to higher quality hay. It reduces, after mowing, the loss that results from long exposure in the field and handling the hay crop.
Crimping cuts down the risks of obtaining poor hay by shortening the time the crop is exposed to the weather and prevents the mechanical damage that so often goes with outdated haymaking methods. More and more research is being carried out in the world on modern methods of haymaking and time after time this research proves that crimping the crop immediately after mowing is the surest, safest and most desirable way of making higher quality hay. When grass is mown and no special measures are taken moisture is lost rapidly from the leaf and slowly from the stem. When the stem is fit to bale the leaf is so dry that it will shatter when it is touched. It stands to reason that to avoid this it is essential to equalise the drying rate of the stem and the leaf. The longer the crop is left out in the weather the greater is the loss of feed value.
This is the field where the crimper can help by equalising the drying rate of the stem and the leaf which eliminates the most undesirable features of conventional haymaking methods.
The cotton picker
Cotton takes perhaps the leading place among all industrial crops. For the harvesting of cotton up to quite recent times manual methods alone were used. But today, with the advent of comprehensive mechanization, most, if not all, labour-consuming kinds of labour are being taken care of by labour-saving devices. Among them the cotton picker stands out with particular prominence.
The cotton picker is usually tractor-mounted. Sometimes its working mechanisms operate from a PTO. During one pass this machine gathers cotton from two rows of the cotton plant. It consists of two limb-lifters, two doffers with cotton-picking receptacles, two fans, air-ducts and a bin. The limb-lifters raise the laid plants, compress the bottom part of the stalk and feed it into the cotton-picking receptacle.
Here the limbs pass between two rotating drums which with their teeth extract the cotton out of the opened bolls and wind it upon their spindles. Then the drums draw the spindles from the bush and feed it to the doffing brushes which, in rotating, remove the raw cotton.
A current of air passing from the fan through the air- duct now sends the removed cotton into a bin.
The cotton picker is manned by a single operator and it replaces the need to have twenty manual pickers.