plow
A plow is an agricultural device for loosening and turning (plowing) the arable land in the area of the working horizon .
Plow
Plowing is the loosening and turning of the topsoil with the help of a plow. The soil structure is loosened by plowing . This results in a larger, rough surface. A loose structure is achieved through increased oxygen supply, the effects of the weather and the decomposition of organic substances. For the purposes of the (possibly first) preparing a soil as a farmland by plowing is also called break .
The purposes of plowing are:
- Aeration of the soil with the resulting biochemical decomposition of older plant material ( soil fermentation ) into humus - according to some experts, plowing also leads to more or less severe humus loss and thus to the impairment of soil life, water storage capacity, soil carbon storage and the release of climate-relevant gases
- Uniform and covering incorporation of crop residues or organic material applied to the field (e.g. manure , liquid manure , chopped straw )
- mechanical weed control
- Control of animal pests , especially field mice , by destroying the tunnels and nesting chambers below the ground surface
- mechanical loosening of the soil, especially of compacted areas
- Preparation of the field as a seedbed
As a rule, plowing is done in a square with a reversible plow or bed plow, or in strips if the rain (field edge) is wide enough . When contour plowing (amerik. Contour plowing ), the grooves are laid parallel to the slope, the erosion (Hangabspülung) to decrease. This was mainly cultivated in the American Great Plains .
The success of plowing depends on the right time, the working depth adapted to the soil and the weather. If this is not observed, the plow can cause considerable damage to the soil structure. Usually plowing takes place in autumn. Large clods of earth can then disintegrate over the winter due to frost bursting. Because of the soil organisms and the humus layer, it should not be plowed too deep. To prepare the seedbed, fields are then smoothed (“harrowed”) with the harrow .
History of the plow
The earliest method to loosen up the ground was still today in many parts of the world used digging or furrows floor, which offered a certain leverage and could be used to draw flat seed grooves. Small areas of the soil were loosened with hoes. This was followed by plow-like implements pulled by humans (pull stick, pull spade). Already in prehistoric times the plow replaced hoes or spades as well as digging , furrowing and planting sticks for field work in many places .
Ritz plow
Early forms of the plow seem to have been invented in parallel in different cultures of the Neolithic Age ( Harappa , Starcevo ). These first forms were Ritz plows, which are technically referred to as Ard or Arl . They had a symmetrical wooden point that was later reinforced with iron plates. Since it only slightly scratched the top layer of soil in a one-off operation, the plowing of the field was made in two directions. This type of cross plowing has been carried out since the Neolithic and has persisted into modern times in some places, especially in the Mediterranean region .
The earliest find of a digging stick or hook plow in Europe comes from “ Egolzwil 3 ” in the canton of Lucerne and dates to the middle of the 5th millennium BC. Traces of furrows were found on the burial ground of Flintbek , Rendsburg-Eckernförde district, Northern Germany as well as under megalithic systems and in settlements in the Netherlands and Denmark. This region was founded around 4300 BC. Populated by the funnel beaker culture (TBK). These hook plows, which consisted of a digging stick, have a plow head, curved upwards and set in the rump, are pierced by the tree and were pulled by oxen .
The oldest wooden plow found in Germany is the crumb plow from Walle in East Friesland . First in the 4th millennium BC. Later (in the 1950s) classified in the late Neolithic Age (around 2000 BC), more recent measurements now date the plow to the early Bronze Age (1940 to 1510 BC). A characteristic of the crumb or bow plow is that the crooked tree (also called crumb), sole and share are made from one piece of wood; In addition, there is only the rump, which is inserted into the rear protruding end of the sole behind the crooked tree and fixed with wooden wedges. Such hook plows survived in Central Europe until the late Middle Ages ; the southern German names Arl or Erling 'Ritz-, Krümelpflug' were borrowed from Slavonic.
Jens Lüning assumes that the line ceramists already used the plow. There is indirect evidence for this, such as the oxening of bulls. Most authors assume, however, that the plow, together with wagons, was first used in the funnel cup culture or the Baden culture in Central and Northern Europe. There are plow marks from the time of the cord ceramic .
At first oxen and later cows pulled the plow. Much later, donkeys , camels and mules were added, in Central Europe the more powerful horses in larger farms .
Mesopotamia and Egypt (later also India ) are presumably independent motherlands of the plow. The transition from hacking to plowing in Egypt may have already taken place there during the Naqada II period (3700/3600–3200 BC). A distinction can be made between two types: the animal-harnessed plow ( Sumerian apin , Akkadian ḫarbu , Egyptian hb.w ) to loosen the soil, and the ancient Mesopotamian seed plow (Sumerian numun-gar , Akkadian epinnu ) with a seed hopper, with which a uniform sowing is achieved has been. After 3000 BC Ancient Sumerian plows were typically shod with bronze shares; with iron shares after 1200 BC In Assyria and Egypt. At the beginning of the 20th century, plowing in Asia Minor was largely carried out in this simple way.
Soil turning plow
In the 1970s of the 1st century AD, Pliny the Elder describes in his natural history the wheel plow with a wide flock to turn the clod as a new invention of the Rhaetian Gauls : “Not long ago the invention was made in Rhaetian Gaul, on to attach two small wheels to such a ploughshare; this species is called plaumoratum . The tip is shaped like a spade. ... The width of the ploughshare turns the lawn around ”(translation by Roderich König).
In the 4th century AD the wheel plow came on; this concentrates the pulling power of the animal more on breaking up the ground than on pulling the rather heavy device. The use of horses for plowing became particularly effective with the invention of the collar , because the neck and waist belt, which was still used up to the 8th century, impaired the breathing of the draft animal, and the harness that was then used was not much more effective.
The iron coulter was a major improvement. The effectiveness of the plow was improved by the addition of a mouldboard (since plows were made of steel, called mouldboard ) and the knife coulter enormously: the coulter and coulter cutting tools cut out the strip of soil and turned it over from the mouldboard. The vegetation, including unwanted weeds (so-called weeds), is buried and there is only clean soil on the surface. In some constructions there are so-called pre-cutters or colter .
Iron shares (Chin. Guan ) with a sharp point, adjoining central bar and side wings, which are slightly inclined upwards to reduce the friction, for wiping the earth have existed in China since the 3rd century BC. Already at this time - before the turn of the century - there were four types of mouldboards in China, which merged into the ploughshare precisely (i.e. without friction) and turned and thrown the ground differently. Furthermore, you could set the depth at which you wanted to plow the earth on the construction. The knowledge of the construction method was officially spread in ancient China.
The plow developed in the 15th century had a reversible moldboard and a symmetrical share. This made it possible to plow to the right and to the left. This allowed the plow to be turned at the end of the furrow and plowed in the opposite direction.
In Europe, mouldboards were only introduced in the late Middle Ages (initially made of wood) and then built very primitively until the 18th century, so that there was great friction losses and more draft animals were needed for the same work. It wasn't until the 18th century that a serious rethink began with Rotherham Plow . A pioneer in the field was James Small (around 1730–1793), whose plows were established in England and Scotland (but not yet in Germany) for 150 years.
In 1809 the village blacksmith Pangraz Fuchs in Wagersbach manufactured the Fernitzer plow in Styria . The specially attached coulter was an innovation to the plows that were common in the region at the time. The type of attachment to the leg was new. He got the name Fernitzer Pflug because Wagersbach belonged to the Fernitz parish at that time . At the instigation of Archduke Johann , this plow soon spread throughout the entire Danube Monarchy .
Between 1824 and 1827, the cousins František (1796–1849) and Václav Veverka (1799–1849) from Rybitví constructed the first steeply turning dump plows (Ruchadlo), whose mouldboard has a cylindrical, inclined shape that bends the plowed strip of earth around its transverse axis so breaks and crumbles.
The American blacksmith John Deere invented the first self-cleaning steel plow in 1837 and thus laid the foundation for his company Deere & Company, which is now the largest manufacturer of agricultural machinery in the world.
When the forerunners of tractors came into the fields around 1900, they were called "power plows".
Construction of the plow
The plow body in its entirety consists of:
- Crowd
- The knife that cuts the soil horizontally , sometimes divided into pre-cutting chisels (fore-share) and the actual main share that cuts after, is attached to the mouldboard. Twin shares (double share) on sweeping plows were very common in the earlier draft animals.
- Mouldboard
- Also Riester , elm , furrows turner , elm board and moldboard called, was initially and just like wood. The modern mouldboard has a helical or cylindrical shape and turns the soil cut by the share to the side. Often supplemented by a brush rail to safely turn the floor.
- sole
- Agricultural also called plant or main, is a flat steel strip, which supports the side pressure generated by the mouldboard and share towards the unploughed land, the important prerequisite for plow control.
- Semolina column
- also brisket or grits; Gries at the column top of the Grindelstrasse , front mold board and the blade and laterally fixes the sole. The semolina holds the plow body together.
- Grindel
- also called gudgeon, grendel, plow beam, (plow) tree or frame, is the connection of the plow body to the pulling point.
- Sterzen
- one calls the control handles in draft animal plowing; on older swing plowing also armed rumps can be found.
If the plow has a helical mouldboard, it is referred to as a screw body , otherwise it is called a cylindrical body. The helical body turns around 110 to 115 degrees, the cylinder body up to over 135 degrees. The transitions are fluid today. The more cylindrical the body, the better the plow turns and crumbles, but screw bodies can be driven faster and are easier to pull. Grassland is turned very cleanly by screw bodies.
The strip body is a special form . Here the mouldboard does not consist of just one, but of several strips. Strip bodies are used on particularly heavy, sticky soils as well as on bog soils. In comparison to undivided mouldboards, tensile strength savings are possible there. A better crumb result can be achieved by using different angles in the longitudinal direction of the strips.
The main body is often preceded by a preparatory tool or a combination thereof, as required. The preparatory tools support and improve the work of the plow body:
- Six
- The knife coulter , regionally known as Coulter or taper, cuts the to be turned Erdbalken vertically from unplowed land. Using the coulter results in a clean furrow wall (e.g. when plowing grassland) and protects and protects the front mouldboard edge of the plow body. In addition to the knife coulter attached to the frame, there is also the so-called system coulter attached to the sole (system) .
- Disc coulter
- This preparatory tool, also known as the round six, has the same task as the knife-shaped six, but is easier to pull. A round sheet metal disc rolling in the ground cuts the earth bar to be plowed from the unploughed land.
- Jointer
- When Vorschäler (also Vorschneider ) is small plow body, which decreases in half working width of the main body, the top layer of soil and bears at the previously flipped Erdbalken laterally. When using skimmers, it is possible to plow very deeply with a smaller working width, and the placement of weeds is improved.
- Fertilizer skimmers
- This is similar to the skimmer, but has a rounded mouldboard leading edge and a greater difference in working depth between the share point and the share rear edge. The manure skimmer turns the top layer of soil with manure that was distributed before plowing and places it on the previously turned earth beam so that it is not worked under too deep to avoid charring of the manure.
Plowing with draft animals
The plows pulled by draft animals (ox, cow, donkey, mule and horse) are divided into:
- Swing plow
- no wheel for guidance; the plow is controlled by the type of attachment and by the team driver over the runners in terms of working depth and width.
- Stilt plow
- a wheel or a skid is in front of the share, the clamping takes place directly on the plow beam.
- Cart plow
- the plow beam rests on a two-wheeled cart, which carries the tensioning of the plow.
plow from 1922: 1 plow tree, 2 stiffeners, 3 handle, 4 stiffener struts, 5 wrenches, 6 right furrow wheel, 7 wheel tires, 8 wheel bushes, 9 left land wheel, 10 cart brackets, 10a drawbar brackets, 11 bracket struts, 12 plow tree carriers, 13 Pull chains, 14 plow beam support rod, 15 cart axle, 16 pull plate, 17 handle for skimmer system, 18 mouldboard for skimmer, 19 share for skimmer, 20 clamp for skimmer, 21 knife, colter or coulter, 22 clamp for that, 23 plant with semolina column, 23a small sole right, 24 trowel, 25 share, 26 trowel, 27 double sole, 28 T-sole piece, 29 screws for the head system, 30 drawbar with draw hook
- Frame plow
- in which the plow bodies are not attached to a leg, but to a frame supported by two to four wheels.
From the Middle Ages, the plows had two handles at the rear end to guide the plow and to steer it to a limited extent. The main innovation was the of the wooden frame ( Grindelwald fortified) iron plow body with share and moldboard. In common usage today, the plow body is still referred to as a share; correctly designated, this is only the soil-separating part of the plow body.
Reversible plows have been developed for plowing back and forth in one direction. Examples for this are:
- the double-share reversible plow, also known as the reversible plow; the coulters ( twin coulters ) mounted on the same mouldboard opposite can be brought into working position by rotating the plow body around a horizontal axis and thus the turning direction can be changed (due to its inexpensive design, it was once a common type of swept plow for draft animals).
- the reversible plow, in which the mirror-inverted plow bodies, offset by 180 degrees, are attached to a rotatable leg.
- the tilt plow , the opposite plow parts are used on the return journey in the same furrow (more expensive construction, but less effort required to change the working direction at greater working depths).
In large farms with horse harnessing, multi-furrow bed or sweeping plows with self-control, i.e. without streaking, and trench plows were used for subsoil loosening. The Wanzleber plow enabled the deep plowing necessary for successful sugar beet cultivation.
Plows for animal train are still used in large numbers today. B. made in India.
Three-in-hand plow in heavy soil
Autumn furrow with a double team in 1949
19th century cart plow
Team of oxen in Tibet 2014
Plowing without draft animals: full mechanization of plowing
The age of fully mechanized plowing began in Europe from around 1850 with the steam plow . In 1858 the British Royal Agricultural Society awarded the English engineer John Fowler a prize of 500 pounds for the development of the steam plow, which they had offered for an economical replacement of the plow or spade. These were Locomobile , drawn up at the end of the field to attend winches back the plow on the field and move here. The heavy traction engines could only be used economically in large agricultural operations and were unsuitable for pulling the plow directly. In the second and third decades of the 20th century, lighter tractors with internal combustion engines were developed (e.g. Fordson , Bulldog or Hanomag WD) that made it possible to pull a trailed plow directly over the field. At the beginning of the 20th century, the Julius Kemna company became the "leading steam plow company on the European continent and penetrated the world market into the monopoly of English companies".
A large number of different plow shapes were created, which are pulled by tractors of different performance classes. The plows of the early tractors often only had one plow body, so they were "single-share". However, there were multi-blade plows, i.e. those with several bodies in a row, for early tractor models. Three- and multi-furrow plows are often equipped with a variable furrow width adjustment (Variopflug).
Tilting plow for "steam plowing"
Historic tipping plow for rope hoist (Museum Cloppenburg)
Trailed bed plow for tractor train
Variopflug
Today's designs of plows
construction
On a steel frame (plow frame or leg) there are on the one hand connection options with a tractor, on the other hand plowshares and coulter are screwed on. There are both single and mostly multi-furrow plows in use. The coulters are arranged in a row at an angle, depending on the respective cutting width. The different designs are described below.
Attachment types
- Trailed plow
- Plow that is coupled to a tractor but is lifted manually. This type of plow was widespread until the advent of agricultural tractors with hydraulic systems . A special form was the steam plow , which was pulled across the field by one or two stationary steam-powered locomotives with a cable winch.
- Mounted plow
- Plow that is permanently attached to the tractor and is brought into the transport or working position by means of three-point hydraulics . Today mostly 2 to 8 furrows.
- Semi-mounted plow
- Plow with its own chassis (1 or 2 wheels) that carries part of the plow weight. Today mostly from 6 furrows and usually in Europe up to max. 20 shares can be realized.
Mounted four-furrow reversible plow with disc coulters
Semi-mounted plow
Plow type
- Bed plow
- Plow with a row of shares that turns the soil only in one direction, usually to the right. Larger fields must therefore be divided into smaller "beds", hence the name bed plow.
- Reversible plow
- Plows of various designs with right- and left-turning shares, which enable the U-turn and return in the last furrow at the end of the field. A distinction is made between:
- Reversible plow;
- Plow with right- and left-rotating shares, which face each other vertically and are brought into working position by a full turn of 180 degrees (common plow type).
- Angled reversible plow
- Plow with right and left rotating shares, which are attached at a 90 degree angle to each other. This form was particularly widespread in small farms (only found in gardening centers and small hobby farms).
- Tilt plow;
- Plow with right and left rotating shares, which face each other in the pulling direction and are brought into working position by tilting (only individual pieces can be found).
Special plow shapes
- Front plow
- A plow that is attached to the front linkage of the tractor and thus pushed. This form is more common in France. In most cases, this involves 3–4 furrows reversible plows, which are operated in combination with a plow attached to the rear of the tractor. By adding a front plow, the tractor axles are loaded more evenly, but the maneuverability of the tractor while plowing is impaired.
- Hoe plow
- The hoe plow usually has a central goosefoot share and 2 or 4 additional shares, which can also be angle shares . This device loosens the soil between rows of plants and performs mechanical weed control.
- Ridging plow (ridger)
- With the ridging plow, there is a symmetrical coulter on the plow body that penetrates the earth with its tip and a mouldboard that turns left and right. This creates furrows between which the thrown up earth forms dams, such as those required in potato and asparagus cultivation. The mouldboards of the ridging plows are partially adjustable to change the size of the dam.
- Ditch plow
- Similar to the ridging plow, the ditch plow, with which about 50 cm wide trenches can be dug for planting asparagus , for example , has a wedge-shaped share and two mouldboards arranged next to one another.
- Potato plow
- The potato plow is used to lift potatoes . Similar to the ridging plow, the lifting plow also has a symmetrical share. The share drives under the potato dam to be cleared and loosens it. Instead of mouldboards, the coulter is followed by an inclined grate made of round steel rods, which is intended to sieve the loosened earth so that the potatoes come as close as possible to the surface for easier manual picking. The further technical development with the lifting share and blast wheel is the potato harvester .
- Rotary plow
- Plow in which the mouldboard is designed as a vertically rotating cylinder, which is driven by the tractor's PTO shaft via a belt drive . The aim of this design by the Raussendorf company was to achieve a higher area performance by reducing the slip on the tractor wheels. (Plow shape examples can only be found here and there).
- Plow
- light plow with small shares and a working depth of 5 to 10 cm. The goal: to quickly compete plant residues after harvesting through low soil cover and at the same time to create a simple seedbed for catch crops. (Today largely replaced by rotating farm implements).
- Disc plow
- Plow made of plate-shaped steel disks attached diagonally one behind the other . The difficult tractive force curve of this plow (at an angle to the direction of travel) only allows shallow furrows or use for stubble cultivation. The pulling force problem was solved by counter-rotating plates on the disc harrow . However, a higher area performance and better soil mixing than a plow means a less favorable seedbed for stubble sowing . Disc plows are only of historical importance; the disc harrow for stubble cultivation has largely been replaced by rotating machines or tools on seed drills ( drill seeding , direct seeding ).
- Layer plow
- Plow with shares attached one above the other, whereby the upper share turns the soil flat (up to approx. 15 cm) and the lower “loosening share” loosens the soil, but does not turn it (from 15 to 30 cm depth). This plow for loosening the subsoil can be used both after lane damage and for compaction of the plow sole .
- Swivel plow
- Plow with symmetrical plow bodies in which the turning direction to the right or left is changed by pivoting the frame around a vertical axis. The swivel plow is cheaper to manufacture than a reversible plow due to its simple design; However, the quality of the plowing work depends on the condition of the soil; clayey, moist soils cannot be worked with the swivel plow at all.
- Deep plow
- Plow with share and oversized mouldboards for cultivating peatlands, also called rigol plow, rajol plow or deep plow, see deep plowing .
Ditch plow
Hoe plow for animal tension
Ridging plow
Potato plow for draft animals
Disc plow
Swivel plow
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Manufacturer
Manufacturer of horse-drawn plows:
Helwig, Eberhardt , Landsberg , Rud. Sack , Ventzki, Printz, Hildebrand
Former manufacturers:
Eberhardt, Eicher , progress , Krone , Landsberg, Frost, Vogel & Noot
Current Manufacturers:
Amazone , Gassner, Grégoire-Besson , Kongskilde , Kuhn , Kverneland , Lemken , Pöttinger , Rabe , Regent, Niemeyer Agrartechnik
Plowing competitions
While regional plowing competitions with draft animals has been documented since 1855, state, federal, European and world championships in plowing with tractors have only been held regularly since the middle of the 20th century. In 1952 the World Plowing Organization (WPO) was founded. The WPO organizes the annual world championships in plowing . In 1953 the first world championship was held in Canada. World championships were held in Germany in 1958, 1978, 1998 and 2018. Austria hosted the World Cup in 1964, 1987 and 2008. The 61st World Cup took place in France in 2014 .
Young farmers compete against each other in different age groups and plow categories for performance plowing . The rules are set internationally and are recognized by all participating country organizations; the ploughmen are left to their own devices, help and advice from other people are not permitted. The court of arbitration primarily assesses the straightness of the furrows, their constant depth, the uniform appearance of the plowed field and the speedy work. A memorial in Haringsee commemorates the World Cup in Austria (1964) . Plowing competitions have a long tradition there and Austria is considered the most successful nation in the history of the Plowing World Championship with 15 world championship titles and 7 vice world champions, ahead of Northern Ireland.
Reigning world champions (2014) are Eamonn Tracey from Ireland and Andrew Mitchell senior from Scotland.
heraldry
The plow has also found its way into heraldry . Strongly stylized, it is a common figure in the coat of arms as a sign of important agriculture . Even just a ploughshare is gladly accepted.
symbolism
In some cultures, the plow is a symbol of fertility, as plowing prepares the fields for sowing. Plowing is equated with fertilization.
See also
literature
- Paul Readers : Origin and Distribution of the Plow . (= Anthropos. Ethnological Library. Volume 3, No. 3). Aschendorffsche Verlagbuchhandlung, Münster i. W. 1931. (Reprint: The International Secretariat for Research on the History of Agricultural Implements, National Museum, Brede, Lyngby (Denmark) 1971)
- Ulrich Bentzien: hook and plow . Berlin 1969.
- Max Eyth : Behind the plow and vice . DVA, Munich 1987, ISBN 3-421-06303-6 .
- Gustav Fischer : Agricultural machinery. Publishing house Eugen Ulmer, Stuttgart 1928.
- Tim Kerig: 'When Adam was digging ...' Comparative remarks on farm sizes in prehistoric times. In: Ethnograph-Archäolog. Magazine Volume 48, 2007, pp. 375-420.
- Michael Koch: Traditional work with horses in the field and forest. 1st edition. Verlag Eugen Ulmer, Stuttgart 1998, ISBN 3-8001-7383-2 .
- Klaus Krombholz, Hasso Bertram, Hermann Wandel: 100 years of agricultural engineering - from handcraft to high-tech in Germany . DLG-Verlag, 2009, ISBN 978-3-7690-0737-4 .
- Horst W. Löbert: From the history of the plow . (= Lüneburg Heath Agricultural Museum. No. 5). Uelzen 1993.
- Jens Lüning: Stone Age farmers in Germany. Agriculture in the Neolithic. Bonn 2000.
- Karsten Möller among others: tillage . (= Top Agrar. Special edition 2014). Landwirtschaftsverlag, Münster.
- Manfred G. Raupp: What the grandfather already knew . Staffort / Lörrach 2005, DNB 989985555 .
- Paul Schweigmann: The agricultural machines and their maintenance . Giessen 1955.
- Ursula Tegtmeier: Neolithic and Bronze Age plow tracks in Northern Germany and the Netherlands Bonn 1993, ISBN 3-86097-136-0 .
Individual evidence
- ↑ Bernhard Göbel: Influence of tillage on the humus content. (PDF) June 11, 2013, accessed on August 8, 2019 .
-
↑ Leaflet on combating field mice from the Thuringian State Agency for Agriculture from July 2012 ( Memento from December 19, 2013 in the Internet Archive ) - (PDF; 104 kB).
Press release of the German farmers' association of July 12, 2012: Field mouse plague in Thuringia and Saxony-Anhalt, farmers lack the means to combat it . - ^ André-Georges Haudricourt, Mariel Jean-Brunhes Delamarre: L'homme et la charrue à travers le monde. 2nd Edition. La Manufacture, Lyon 1985.
- ↑ The Flintbek burial ground on the website of the Bordesholm History Association.
- ↑ Dirk Hecht: The cord ceramic settlement system in southern Central Europe. A study on a neglected genus of finds in the transition from the Neolithic to the Bronze Age (PDF; 34.2 MB). Dissertation. Heidelberg 2007, p. 197.
- ↑ Jens Lüning: Ceramic plows? In: Fund reports Hessen Volume 19-20, 1979-1980, pp. 55-68.
- ^ Peter Bogucki: Animal traction and household economies in Neolithic Europe. In: Antiquity. Volume 67, No. 256, 1993, pp. 492-503.
- ↑ Tim Kerig: 'When Adam dug ...' Comparative remarks on farm sizes in prehistoric times. In: Ethnographisch-Archäologische Zeitschrift Volume 48, 2007, pp. 375-420.
- ^ Karl Kaser: Balkans and Middle East. Introduction to a common story . Böhlau, Vienna 2011, p. 138.
- ^ Paul Schweigmann: The agricultural machines and their maintenance. Giessen 1955, p. 18 f.
- ^ Horst Eichhorn: Landtechnik. 7th, completely revised edition. Ulmer, Stuttgart 1999, ISBN 3-8001-1086-5 , p. 156.
- ^ Horst Eichhorn: Landtechnik. 7th, completely revised edition. Ulmer, Stuttgart, 1999, ISBN 3-8001-1086-5 , p. 163.
- ^ German biography: Kemna, Julius - German biography. Retrieved July 18, 2020 .
- ↑ B. Fischer: Agricultural engineering. Verlag Ulmer, Stuttgart 1928, Fig. 256 (two-share plow for Hanomag WD from Sack), prospectus from Printz, Kettwig (Ruhr) (also two-share plow for Hanomag WD), accessible in the company documents archive of the Deutsches Museum, Munich
- ^ Alfons Eggert, Hans W. Mattig: Aschendorffs tractor book. Aschendorff, Münster 2000, ISBN 3-402-05261-X , p. 81.
- ↑ Ulrich Sachweh (Ed.): The gardener. Volume 3: Nursery, fruit growing, seed growing, vegetable growing. 2nd Edition. Ulmer, Stuttgart 1986/1989, ISBN 3-8001-1148-9 , p. 13.
- ↑ Example of a rotary plow ( Memento from February 11, 2013 in the web archive archive.today ).
- ↑ Fuel consumption with two-shift plow, PDF from the University of Natural Resources and Life Sciences in Vienna ( Memento from June 5, 2015 in the Internet Archive )
- ^ Horst Eichhorn: Landtechnik. 7th edition. Ulmer, Stuttgart 1952, 1999, ISBN 3-8001-1086-5 , p. 158.
- ^ Website of the company Niemeyer-Agrartechnik
- ↑ Competition plowing with draft animals in Bohemia 1855
- ↑ Performance plowing in Germany; German Ploughman's Council
- ^ Homepage of the World Plowing Organization
- ↑ 2014 World Plowing Championship
- ↑ Chronicle Fuchsenbigl with monument to the world championship in plowing
- ↑ Udo Becker: Lexicon of symbols . Nikol Verlag, Hamburg 2012, ISBN 978-3-86820-139-0 , pp. 227 .
