Two-wheel tractor

Two-wheel tractor in Italy (2008)

Two-wheel tractor or walking tractor are generic terms understood in the USA and in parts of Europe to represent a single-axle tractor, which is a tractor with one axle, self-powered and self-propelled, which can pull and power various farm implements such as a trailer, cultivator or harrow, a plough, or various seeders and harvesters. The operator usually walks behind it or rides the implement being towed. Similar terms are mistakenly applied to the household rotary tiller or power tiller that may be wheeled and/or self-propelled but often is not. A further distinction is seen in the two-wheeled tractor's ability to operate disparate types of agricultural equipment, while rotary tillers are smaller and specialize in soil tillage. This article concerns two-wheeled tractors as distinguished from such tillers.

Confusion over definition

Research has identified a number of terms used to identify two-wheel tractors, including "iron-ox; walking tractor; Kubota; mechanical ox; ox-machine; power tiller; rotary hoe, rotary plough, rotary tiller; Rotavator, [and] tok-tok".^[1]

"Power tiller" can be understood as a garden tiller/rototiller of the small (3–7 hp or 2.2–5.2 kW) petrol/gasoline/electric powered, hobby gardener variety; they are often sold as a rotary tiller, though the technical agricultural use of that term refers solely to an attachment to a larger tractor. Alternatively, the terms "power tiller" or "rotary tiller" are always understood in Asia and elsewhere to be rubber- or iron-wheeled, self-propelled machines of 5–18 hp (3.7–13 kW) and usually powered by heavy-duty single-cylinder diesel engines (many Asian countries historically have had a high luxury tax on petrol/gasoline). Adding to the nomenclature confusion, agricultural engineers like to classify them as single-axle tractors. For clarity, the rest of this article refers to the self-propelled, single-axle, multi-attachment tractive machines as two-wheel tractors.

For production agriculture, past and present, two-wheel tractors are offered with wide range attachments such as rotovators, moldboard, disc-plow and spike-tooth harrows, seeders, transplanters, and planters. Even zero till/no-till planters and seeders have become available. In plant protection two-wheel tractor attachments consist of various inter-cultivators and sprayers. For harvesting mowers, reaper/grain harvesters, reaper-binders, and even combine harvesters are available for them. For transport, trailers with capacities from 0.5 to 2 plus ton cargoes are available. All the chores done by larger 4-wheel tractors. This confusion or misunderstanding runs deep even at research and institutional levels. The United Nation's Food and Agriculture Organization's own statistical database, FAO Stat ^[2] gauges levels of mechanization by numbers of 4-wheel tractors and ignores completely the fact that 2-wheel tractors perform exactly the same work that 4-wheeler tractors do. By using FAO's statistics, international donors and agricultural research and development centers assume that since Bangladesh and Sri Lanka have very few 4-wheel tractors, that they are completely unmechanized, as compared to India, who besides having 100,000 two-wheel tractors also has a large population of 4-wheel tractors. Yet, when two-wheel tractors are included, Bangladesh and Sri Lanka are the most highly mechanized countries in south Asia, in terms of area under mechanized tillage operations.

Early history of two-wheel tractors / power tillers

Germany

Two-wheel tractor with trailer (2007)

In 1910 Dr. Konrad von Meyenburg of Basel, Switzerland, applied for a patent for a "Machine for Mechanical Tillage" Patent Number 1,018,843 was granted on February 27, 1912. He then licensed his patent to Siemens-Schuckertwerke of Berlin, Germany. Siemens an electrical manufacturer built their first two-wheel tractor with rotovator Bodenfräse (rotovator or literally soil grinder) using an electric motorized two-wheel tractor and a long extension cord in 1911. The idea was quickly abandoned and Siemens began using two and four cycle single cylinder internal combustion engines to power their two-wheel tractors. Around 1932 Siemens sold off its cultivator division and focus on its electrical applications. Mr. Eberhard Bungartz of Munich, Germany a trailer manufacturer purchased the division in 1934 with all patents, parts, and machinery and went into production using the Bungartz name.^[3].

United States

Mando "Steve" Ariens, having just taken over the reins of his fathers' Brillion Iron Co had to declare bankruptcy in 1932 at the height of the American Depression. In 1933, in his father Henry's garage and Steve's basement he and his father developed first Ariens Rotary Tiller, a 30" tiller, powered by a front-mounted four-cylinder, V-type, 14 hp (10 kW) engine ^[4].

In 1930 Cadwallader Washburn "Carl" Kelsey an automobile manufacturer, was introduced to the rototiller by H.B. Hiller an German immigrate who once worked for Siemens' "boden frasen" division. Kelsey opened a sales office using the name Rototiller Co. on Broadway in New York City. He then started importing Siemens boden frasen from Germany. In 1932, Kelsey incorporated using the new company name Rototiller, Inc. and the "Rototiller" trademark (Kelsey didn't coin the name 'Rototiller' it was already being used in Europe). The operation was moved to Long Island City, NY. and SIMAR from Switzerland was added to the line. Carl Kelsey designed, patented and made several improvements to the SIMAR and Siemens machines because of the different American soils versus the European soil that had been farmed for many more centuries. One major improvement was a shock absorber to reduce tine spring return bounce. In 1934 Kelsey and Rototiller, Inc. introduced its first rotary tiller of its own design, the Model AA All-American. And in 1937 Rototiller, Inc. moved from its Long Island City facility to 102nd Street and 9th Avenue in Troy, New York. In 1945 after selling the larger B-series Rototillers and trademark to Graham-Paige Motors, Rototiller, Inc. converted to full time production of various models of small horsepower home garden size rototillers. In quick succession in 1959 and 1960, Rototiller, traded hands from Porter Cable Company of Syracuse, N.Y. (and was eventually moved to Syracuse) and then by Rockwell Manufacturing Co. of Pittsburgh in 1960. The rear-tine rototiller business continued to decline and Porter-Cable sold its Rototiller and small engine division to Moto-Mower Division (Richmond, Indiana) of the Dura Corp. of Detroit (formerly Detroit Harvester) according to a May 10, 1962 article in the Richmond Palladium-Item & Sun-Telegram. In 1961 Rototiller, Inc. and the Roto-Ette trademark disappeared.

As early as 1911 Benjamin Franklin Gravely of Charleston West Virginia began with connecting the Indian motorcycle to a manually operated push plow.^[5] In 1916 he incorporated and after obtaining partners and began producing single-wheel tractors and attachments under the name Gravely Tractors. The Model "D" Gravely Power plow like the prototype, was a single wheeled affair, with a 2 horsepower (1.5 kW), air cooled engine. It wasn't until 1937 that Gravely introduced the Model L two wheeled tractor with a 5 horsepower (3.7 kW) engine.^[6] Gravely to this day continues making a wide range of two-wheel tractors concentrating on commercial lawn and garden implements and is a division of Ariens.

In 1915, Rush Hamilton of Healdsville, California, invented the concept of "grouser" drive wheels for his tractor which came with an articulated two iron-wheeled sulky to which wagons or plows could be attached. It was about this time that he formed the Hamilton Tractor Co. About 10 years later, the wheels were called “Hamilton wheels” when used on a Fordson. In 1916 he joined the Fageol Motors Co. where he assisted in the development of the Fageol tractor.^[7]

Early history of two-wheel tractors in Asia

Japan

Japanese model at work

Japanese entrepreneurs began to indigenously design and manufactured two-wheel tractors in the early 1920s. According to Francks (1996) an Okayama farmer Nishizaki Hiroshi (b. 1897) was returning from the WWI determined not to walk behind his father's draft animals and began experimenting with attaching a plow to the newly available small horsepower kerosene engines that farmers were beginning to use for pumping water and threshing. Nishazaki saw a Swiss made garden tractor (? SIMAR ?- Société Industrielle de Machines Agicoles Rotatives ) being demonstrated through a Japanese government technology demonstration initiative in a nearby village (The Japanese agent of the Swiss machine company stopped importing by 1925 as the machine reportedly proved not capable of handling Japanese heavy rice soils). By 1926 Nishizaki had made his first version from diesel powered engine connected by a belt to rotating blades mounted on a wooden frame with two wheels. Soon he began renting it out to neighbors. And as with all good ideas soon local multiple small workshops entered the scene producing various versions. By 1938 there were 22 manufacturers in Japan with 17 of them in Okayama. By 1939 there were over 2800 two-wheel tractors/rotovators in use in Japan. But by the early 1940s nearly half of all the machines were out of commission due to lack of quality and spare parts. After WWII small 2-wheel tractors were imported from the United States and were mainly intended for use in transportation/pulling carts and small trailers. As these gained popularity many Japanese manufacturers "...taking hints gleaned from foreign machines..." started production using the American as their initial model (Francks 1996: 789).

Farmers quickly found that 2-wheel tractors were more economical to use, as compared to keeping animals for tillage and 2-wheel tractors began selling widely. Agricultural machinery dealers received cattle for the barter for tractors and they and in turn sold the cattle in the meat market. Average tractor horsepower per hectare in 1950 was nearly zero. This average grew to 0.86 PS per hectare within ten years with the rapid spread of 2-wheel tractors. Trailer attachments were also being widely utilized for transportation.

Matsuyamasuki, presently known as Niplo brand, invented the Japanese style mold board plow to be attached to 2-wheel tractor, that made plowing with a moldbard possible with 2.5 horsepower (1.9 kW) tractors.

Though four-wheel "riding" tractors began to spread in 1960s, and are taking over primary tillage operations, 2-wheel tractors are still popular in Japan for primary tillage and inter-cultivation in vegetable production, transportation around the farm, etc. Most farm households that own a 4-wheel tractor also own at least one 2-wheel tractor.

India

Interest in two-wheel tractors in India began with special government programs in the 1960s that aided in setting up multiple joint ventures with Japanese two-wheel tractor manufacturers. Initial government prospects for two-wheel tractors was very high (targets were set at 100,000 two-wheel tractors sold per year by mid-1970s). To meet these expectations the Government of India expanded its efforts to include government subsidies, and greatly increased research, development and extension programs for two-wheel tractors. Despite these efforts two-wheel tractor adoption has been disappointing. Especially so when current number of two-wheel tractors estimated at 100,000 are compared with neighboring Sri Lanka's and Bangladesh's two-wheel tractor populations of 120,000 and 400,000 respectively- countries that are a fraction the size of India but with very similar agricultural and socio-economic systems. There have been many reasons offered and even official investigations into the low adoption rates.^[8] One main reason given here is that prices of the joint venture Indian-Japanese two-wheel tractors are twice as expensive as compared to the nearly identical Chinese made two-wheel tractors available in Sri Lanka and Bangladesh.

Indian manufactures that did not survive are: JK Satoh Agricultural Machinery Ltd. a collaboration between JK Cotton Spinning and Weaving Mills Ltd (based in Kanpur, UP) and Satoh Agricultural Machinery Ltd., Japan, began production of two-wheel tractors in a plant with a capacity of 6000 units per year but from its beginning in 1972 till closure of the plant in 1977 only produced and sold 800 units.

Bangladesh

History of two-wheel tractors began with efforts in the late 1970s to promote Japanese imported two-wheel tractors. Adoption remained low through most of the 1980s. In 1987 a large cyclone killed much of the livestock and bullock population. With no prospect timely restoration the bullock population the government began to allow what they once considered inferior quality Chinese two-wheel tractors to be imported to aid in fulfilling farmers land preparation needs. Chinese two-wheel tractors were 50% less cost than the comparable Japanese or Indian manufactured two-wheel tractors and adoption quickly increased, to over 100,000 by 1993, 200,000 by late 1990s and some current estimates put the number at well over 300,000 Chinese two-wheel tractors. Though there has been some criticism on the high cost of imports, others have noted that there is now a very large spare parts industry in support of the Chinese imports.

Thailand

Two-wheel tractor with trailer in Thailand (2004)

The unique long handled "Thai" type two-wheel tractor, was developed in the late 1950's by M.R. Debriddhi Devakul (M.R. stands for Mom Rajawong, meaning that his great grandfather was the King of Thailand, and that he could be properly addressed as "Prince"), head of the Engineering Division of the Thai Rice Department, of the Thai Ministry of Agriculture and Cooperatives. The long handles were made for turning the tractor more easily in wet rice fields. Initially, the tractor had no differential or steering clutches and the engines were kerosene pumping engines. As the popularity of the tractor became obvious (known as the "Iron Buffalo") three Japanese firms set up diesel engine factories in Thailand with agreements to progressively increase local content, which is now nearly 100%. Kubota was the most successful of these three. The tractor was made by many local workshops - everyone copying from each other - and competing for sales to the point that the tractor without engine was very inexpensive, about one third to one half the cost of the engine. Attachments were moldboard and disc plows, harrows, trailed type rotary puddlers (lateral drums with protruding paddles), and trailers. The tractor eventually evolved into a more complex standard "NC" model with three gears forward, one reverse, and steering clutches. Until recently (2010) the Thai models had no PTO but many farmers used v-belts to connect the stationary tractor engine to power water pumps, etc. A new NC Plus model offered by Siam Kubota now comes with a PTO and rotary tiller. The tractors are still made by several Thai companies but recently inexpensive Chinese made NC models have come on to the market. Through the 1980s and 1990s more than 50,000 tractors were reportedly being produced and sold each year ^[9].

Elsewhere

China has the highest numbers that are estimated to approach 10 M, Thailand has nearly 3 M, Sri Lanka 120,000, Nepal 15,000. Parts of Africa have begun importing Chinese tractors and Nigeria may have close to 1,000. Southern Germany, northern and southern Italy, and many countries of central Europe also have significant populations of 2-wheel tractors.

Safety of two-wheel tractors

A number of reports have highlighted safety issues associated with the operation of two-wheel tractors. The most common accidents involve crossing the bunds and road transport.^[10] The operation of two-wheel tractors for transport at night is a recognised hazard in many countries^{[11] [12]}, particularly as single headlights can be mistaken for a motorcycle.^[13] Research undertaken in Cambodia and Laos concluded that two-wheel tractors are involved in around five per cent of fatal accidents.^[14] Occupational health and safety reports have recommended regular breaks for the machine operator due to vibrations.^[15] However, safety researchers have concluded that "the risk to public safety must be weighed against the economic and social benefits."^[16]

Current two-wheel tractor manufacturers in Asia

China

Changzhou Dongfeng Agricultural Machinery Group Co.

Located in Changzhou, Jiangsu Provence near Shanghai Changzhou Dongfeng Agricultural Machinery Group Co. claims to be the only manufacturer in China that owns the Dong Feng brand name. Manufacturing more than 150,000 two-wheel tractors a year in 8, 12, 14 and 15 hp (11 kW) ranges, it has recently expanded into the 4-wheel tractor market manufacturing over 30,000 tractors in the 20–90 hp (15–70 kW) range, under the brand name CHANGTUO.

Jiangxi Kaier Agricultural Machinery Co.,Ltd

From 9hp-20hp,Millions of Walking Tractor are working in Asia's small farms. There is also smaller type(6-9hp) called Mini Tiller. It can be widely meet the hills, mountains, greenhouses, orchards,gardens, paddy fields, such as a variety of different geographical agronomic needs. PENGPAI manufacture 105,135,121,151,181,201 Power Tiller.

India

Kerala Agricultural Machinery Corporation (KAMCO)

Located in Kerala in southern India, KAMCO in cooperation with Kubota, Japan, manufacturers 12 hp (8.9 kW) two-wheel tractor with a range of attachments, a two-wheel tractor walk behind 3.5 hp 120 centimeter reaper and a small 5 hp (3.7 kW) [1]. It currently sells nearly 6500 of its 2-wheel tractors per year.

VST Tiller Tractors Ltd.

Located in Bangalore, VST Tiller Tractors Ltd, part of the VST Group [2] in 1965, in association and joint venture with the Mitsubishi Group, Japan, began production production of single cylinder diesel engines and two-wheel tractors. Currently they offer three versions of its VST Shakti brand two-wheel tractors with rotary tillers. The 13 hp (9.7 kW) VST Shakti 130DI/CT85, the 9 hp (6.7 kW) Mitsubishi Shakti VWH 120/ CT85, and 8 hp (6.0 kW) Mitsubishi Shakti AD 8V/CT85. In 2003 they also began importing Siafeng type 2-wheel tractors from China and marketing them under their Shakti Brand.

Thailand

The Siam Kubota Industry Co.,Ltd.

Located in Bangkok, Thailand, Siam Kubota Industry Co.,Ltd. is a joint venture between The Siam Cement Pcl., Kubota Corporation, Marubeni Corporation, and Min Sen Machinery Co.,Ltd. than began operations in 1978 [3]. They make a range of havesters, 4-wheel tractors and 2-wheel tractors. They offer four models of walk behind (with out sulky seat) and with single and double (steering) clutches.

Vietnam

Vikyno, Southern Agricultural Machinery Company- Vietnam

Vikyno a manufacturer since 1967 of compact diesel engines, four-wheel (including Kubota under 35HP) and two-wheel tractors and agricultural machinery like rice mills and powered reapers. 2WTs models are: - MK55 + Gasoline Engine 168F. - MK70 + Diesel Engine RV70. - MK120S + Diesel Engine RV 125-2. - MK120 + Diesel Engine RV 125-2. - MK120B + Diesel Engine RV 125-2. - MK165 + Diesel Engine RV 165-2.

Current two-wheel tractor manufacturers in the west

United Kingdom

Mayfield Tractors

Mayfield pedestrian tractors appeared on the market sometime about 1949 and were principally designed as a grass cutter in much the same vein as the Allen Scythe. Subsequently a comprehensive range of attachments were available to turn the tractor into a useful tool for the smallholder and market gardener. Assembly was carried out at the Balfour works of S R Wood & Co in Croydon but latterly moved to a site in Redhill, Surrey.^[17]

Germany

Agria

Makers of two-wheel garden and farm two-wheel tractors with a variety of implements. The company was established in post-war Germany in the southwest of the country, in the federal state of Baden-Wurttemberg.^[18] The founder of the Mockmuhl Machine factory was Erwin Machtel, who, together with his partner and Technical Director Dr.Ing. Otto Gohler, managed in 1945 to re-locate the pre-war production line and materials of the Karlsruhe Gears Factory to the neighboring town of Ruschen. In response to the local vintner needs of the time, Machtel and Gohler were encouraged to produce their first non-wheeled power hoe, a project which transported the name Mockmuhl all over the world. Soon the wheeled version followed. In 1948 the 100th machine was sold. In 1958 the 100,000th machine was unveiled at the German Agricultural Fair by the then Minister and later Prime Minister Dr. Lübke. In 2001 the one millionth machine was raffled to the public at the Cologne International Gardening Fair. It was one of the Model 100, which represents Agria's most popular model of power hoe.

Italy

Grillo

Grillo spa began in the Romagna region in the early 1950's developing a farm hoe for weeding in fruit orchards. In 1953 the first Grillo walking tractor was born.^[19] The Grillo winning idea was to detach the motorized tractor from the attachments. It became possible to fit tines, ploughs, and trailers, and via fitting a water pump it was possible to irrigate. In 1955 the factory started the first series production of 15 different models per year. In 1957 "Grillo" became the name of the factory (formerly Pinza) and a brand. In the 1980s the company experienced a considerable growth in the garden machines. In that decade the Grillo research and development department created the first Italian lawnmower with a double hydrostatic system. Today thousands of machines are sold throughout the world annually.

BCS Group

BCS was founded in 1943 by Luigi Castoldi in his workshop in Abbiategrasso, a small town near Milan. The area was and still is highly agricultural. For this reason the motor-mower model 243 was created. This was among the first self-propelled motor-mowers in the world. At the end of the 1960s BCS entered the field of green maintenance machines by producing the first “light” multipurpose two-wheel tractors. Starting in 1970, BCS introduced rotary disc-mowers. In 1988 BCS purchased Ferrari at Luzzara and in 1999 BCS purchased Pasquali at Calenzano; these acquisitions strengthened BCS Group's divisions with two brands with an international reputation. BCS Group presently counts on three production plants (Abbiategrasso, Luzzara, and Cusago) and on six branches.^[20]

BCS Tractors

BCS are makers of two-wheel and four wheel tractors targeting both agriculture and commercial lawn and greens care. Headquarter and factories are located in Abbiategrasso.^[21]

Ferrari

Ferrari is a manufacturer of two and four wheel tractors devoted to agriculture and lawn care. It was created in 1954, during the agricultural reconstruction period of the country. After an initial period dedicated to the production of wire-drawing machines for irrigation pipes, in 1957 Ferrari took part in the Verona exhibition with its first agricultural machine: the two-wheel tractor MC 57, which carries the date of its birth. In 1965 Ferrari launched the first articulated tractor MT65. The range of products was increased to motor mowers and tractors for diverse applications. At the end of the 1960s, the company looked to foreign markets; the subsidiary company Ferrari France was established in 1972. In 1988 Ferrari became part of the BCS Group. Today Ferrari has a wide range of machines between maintenance machines for recreational use and professional tractors for niche agriculture. Headquarters and factories are located at Abbiategrasso.^[22]

Pasquali Macchine Agricole

Founded in 1949 by Dr. Lino Pasquali, the company began production of two-wheel tractors, and in the late 1950s ergonomic improvements such as rubber tires, seat, and steering handles were added. In the late 1960s a line of articulated four-wheel tractors was added. In 1999, the BCS group purchased the Pasquali brand. Pasquali machines work all over the world, with a wide range of motor mowers, two-wheel tractors, and specialized tractors with power up to 100 hp. Headquarters and factories are located at Abbiategrasso.^[23]

United States

Gravely Tractors

Established in 1916, Gravely Tractors began production of two-wheel tractor with moldboard plows costing approximately 170 USD and slowly grew to become one of the most recognized commercial lawn and garden machinery manufacturers in the US.^[24] In 1986 Gravely became a wholly owned subsidiary of the Ariens Company.^[25]

References

1. ^ Ericson, Matthew (2010). 'Two-Wheel Tractors: Road Safety Issues in Laos and Cambodia.' Safety Science 48(5): 537-43.
2. ^ Faostat
3. ^ Donald's Antique Rototillers
4. ^ Ariens >> Corporate Home
5. ^ http://www.gravely.com/about_us/TheGravelyStory.pdf
6. ^ Gravely Page
7. ^ Farm Collector - Rare Walking Tractor Surfaces
8. ^ http://megcooperation.gov.in/model-baproj/model%20scheme3/ae/power_tillers.htm
9. ^ Personal Communication William Chancellor, Professor Emeritus, UC Davis
10. ^ Shridar, B., P. K. Padmanathan, and R. Manian (2006). 'Utilization Pattern of Power Tillers in Tamil Nadu.' Agricultural Mechanization in Asia, Africa & Latin America 37(1): 85-89.
11. ^ Starkey, Paul, Simon Ellis, John Hine, and Anna Ternell (2002). Improving Rural Mobility: Options for Developing Motorized and Nonmotorized Transport in Rural Areas. World Bank Technical Papers No 525. Washington, World Bank.
12. ^ Ericson, Matthew (2010). 'Two-Wheel Tractors: Road Safety Issues in Laos and Cambodia.' Safety Science 48(5): 537-43.
13. ^ Starkey, Paul, Simon Ellis, John Hine, and Anna Ternell (2002). Improving Rural Mobility: Options for Developing Motorized and Nonmotorized Transport in Rural Areas. World Bank Technical Papers No 525. Washington, World Bank.
14. ^ Ericson, Matthew (2010). 'Two-Wheel Tractors: Road Safety Issues in Laos and Cambodia.' Safety Science 48(5): 537-43.
15. ^ Tiwari, P. S., and L. P. Gite (2006). 'Evaluation of Work-Rest Schedules During Operation of a Rotary Power Tiller.' International Journal of Industrial Ergonomics 36(3): 203-10.
16. ^ Ericson, Matthew (2010). 'Two-Wheel Tractors: Road Safety Issues in Laos and Cambodia.' Safety Science 48(5): 537-43.
17. ^ Mayfield Garden Tractor
18. ^ Agria, Agria home, http://www.agria.de/. 
19. ^ Grillo, Grillo home, http://www.grillospa.it/. 
20. ^ BCS Group, BCS Group home, http://www.bcs-ferrari.it/index_group.html. 
21. ^ BCS Agri, BCS Agri home, http://www.bcsagri.it/index.php. 
22. ^ Ferrari Agri, Ferrari Agri home, http://www.ferrariagri.it/index.php. 
23. ^ Pasquali Agri, Pasquali Agri home, http://www.pasqualiagri.it/index.php. 
24. ^ Gravely Tractors
25. ^ Ariens Company

Further reading

• Ericson, Matthew (2010). 'Two-Wheel Tractors: Road Safety Issues in Laos and Cambodia.' Safety Science 48(5): 537-43.[4]
• Francks, Penelope. ‘Mechanizing Small-Scale Rice Cultivation in an Industrializing Economy: The Development of the Power-Tiller in Prewar Japan.’ World Development, 1996. 24(4): 781–796.
• Shridar, B., P. K. Padmanathan, and R. Manian (2006). 'Utilization Pattern of Power Tillers in Tamil Nadu.' Agricultural Mechanization in Asia, Africa & Latin America 37(1): 85-89.[5]
• Starkey, Paul, Simon Ellis, John Hine, and Anna Ternell (2002). Improving Rural Mobility: Options for Developing Motorized and Nonmotorized Transport in Rural Areas. World Bank Technical Papers No 525. Washington, World Bank.[6]
• Tiwari, P. S., and L. P. Gite (2006). 'Evaluation of Work-Rest Schedules During Operation of a Rotary Power Tiller.' International Journal of Industrial Ergonomics 36(3): 203-10.[7]