by Alan Jones
Farming is perhaps the oldest industry in the World. Historians are generally agreed that the earliest implement was probably a crude pointed bent stick or tree branch which was used to stir the soil surface. In affect a hand held hoe in which the user scratched at the earth to form a tilth in which corn could be sown. Early mans struggle for survival became closely linked to the success of his crops and therefore he cultivated more land in order to grow more corn to sustain his life. It soon became apparent that the more the soil was tilled the better the germination and crop quality.
Man continually strived to become more efficient and those hand held hoes soon developed into simple ploughs, well before the early Egyptians over 4000 years ago. These primitive ploughs were eventually pulled by oxen, camels and even elephants and it is said in some instances women were also used. Animals enabled the land to be tilled more easily and faster, thus more food was produced.
The primitive plough made an open shallow furrow by pushing the soil away to either side, rather than inverting as we know today. The ancient Egyptians made considerable advances in its design albeit primitive to our standards. They also succeeded in growing many crop varieties in their dry arid climate by devising complex irrigation systems. As depicted on many of their monuments, the development of the plough from hand held sticks to implements pulled by animals, put them far ahead compared to other civilisations. However, the Greeks were not so far behind and later developed Egyptian ploughs fitted with wheels. These were known as a crooked ploughs because the beam curved forwards to the draft animal. The fitment of wheels provided far greater control and manoeuvrability. Oak was used for the share beam, elm the draught beam and iron for the shares. Iron at that time was very precious, so plough share metal was used and shaped into weapons in times of war. The Romans however, were very efficient with their conquering advances, but their ploughs were simple and crude in design. Although there had been enormous advances from the simple stirring sticks, for these early ploughs to produce well tilled soil, the land would have to be cross ploughed at right angles to the first operation to ensure all the land was well prepared for sowing.
In our own country following the Romans, early British law required every ploughman to make his own plough, and that no one was entitled to use one unless they constructed it themselves. The word 'plough' appears to derive from the Saxon 'plou' and some of the history records show that even Saxon farmers fastened their draft animals to ploughs by their horns or even tails to draw the implement through the soil. This barbaric custom even surviving in parts of Ireland until the 17th century.
There was little attempt to change the design of the plough until the mid 1600's with the Dutch being among the first in improving its shape. This change in shape was soon discovered in Northern England and Scotland with Joseph Foljambe from Rotherham building and patented a plough having what was described as, the perfect implement then in use.
Known as the Rotherham swing plough, because no depth wheel was used, it was like ploughs before it, constructed from wood. The difference was that the fittings and coulter were made of iron and the mouldboard and share were covered with an iron plate. This new design was considered by all who saw it at work to be more efficient and lighter to pull than any other kind at that time. For over 30 years this design proved very popular and was used extensively up and down the country. It was perhaps the first to be factory produced on a large scale.
Man continually experiments to become more efficient and in 1763 a Berwickshire man, John Small, first applied mathematical calculations and science to the mouldboard shape. He experimented with varying mouldboard curvatures and patterns, eventually producing a universal cast iron shape that would turn the soil more effectively with less draft, wear and strain on the ploughman. Over the years this 'Scots Plough' as it was know, was the beginning of the plough we all know today.
Like our ancestors, we continue to strive for improvement. If we take a look at plough development over the last 50 years there has been enormous change. Horse ploughs soon became redundant for more efficient steam units with large multi furrow balance ploughs, quietly trundling up and down fields with only the sound of a whistle to indicate a change of ploughing direction.
Using converted horse ploughs, the more manoeuvrable wheeled tractor slowly took over from steam in the early 1900's and was the start of the format we are all familiar with today. When Harry Fergurson's 3-point linkage appeared in 1920, it totally revolutionised implement attachment and machine performance and has now become the universal norm.
For most of us the last 30 years is relevant, because we too have witnessed many changes in plough design, in what is a very small space in time. For example, the reversible plough now dominates because of its simplicity and ability to produce level fields. An essential part of modern farming practice, with ever larger equipment being employed. Sprayers, combines, sugar beet harvesters to name but a few would not perform to the standards expected unless reversible ploughs were in use. Looking closer, we can pick out some major changes in design which have been necessary to cater for the needs and pressures of farming.
All ploughs now feature hydraulic turnover systems for indexing and hydraulic change-over valves for automatic cylinder stroke direction. The old mechanical lever systems would not be able to rotate today's ploughs, as they are very much bigger and heavier and often out of balance. Hydraulic reversal is also assisted further with main frame alignment. This allows the plough frame to swing in line with the tractor to prevent the rear wheel or bodies from hitting the ground. It also improves stability and reduces the high forces imposed on both the plough and tractor.
Thirty years ago, if you had a 75hp tractor on the farm it was big and in most cases only had two wheel drive. We used to operate ploughs with 56 or 60in. tractor wheel 'centre-to-centre' settings - not any more. Modern tractors feature 4WD, wider wheel equipment and inside tyre settings up to 1800mm to transmit the high horse powers available to the ground. The latest mouldboard designs fitted with furrow bottom wideners unfortunately struggle to cope with these wide tyres and do not operate well in all soils. If wider furrow bottoms are needed, then increases in mouldboard 'throw' are necessary. But, this has the major disadvantage of considerably increasing draft with poor mouldboard performance in sticky soils.
Tractor wheel settings control the plough's front furrow width. Therefore, ploughs have to have a means of front furrow width adjustment to ensure the plough is compatible to the tractor wheel settings. In the days of conventional ploughs, front furrow width was adjusted by rotating the cross shaft to enable the plough to be steered either towards the land or work, thus making the front furrow wider or narrower. Although, some manufactures still use similar steering systems today by angling the plough frame to land or work, this is fundamentally wrong, as it can cause the plough or even the tractor to crab, due to an increase or decrease in landside pressure. The correct way is to move the whole plough literally sideways at 90° to the direction of travel to change the front furrow width setting. This is achieved by using a simple slide and rail system, which provides the result required with very little variation to landside pressure. It also allows for easy fitment of an hydraulic cylinder for on-the-move adjustment when working in hilly areas.
Over the years, furrow widths have increased from as little as 6in. to over 20in. today. Back in the 1930's, horse and early tractor ploughs operated with furrow widths of 6 to 9in. a) because of limited power to pull them, b) horses were still being used extensively on the land. The average width of a horses foot is around 7in. therefore, when land was ploughed and subsequently sown, often by hand, onto what is termed oat seed furrows, sown seed would roll and lay in the 'V' shaped furrow. The ploughing would then be cross harrowed covering the seeds with soil. Once germinated, the seed would be in rows 7in. apart, just wide enough for the horses foot to pass while walking through the established crop.
Early reversible ploughs were constructed from rectangular solid steel bars bolted together to form 'A' shaped sections to which individual bodies were history8.gif (3414 bytes)attached. Using this system on today's large multi furrow ploughs, distortion and poor body alignment, together with supporting the additional weight would be a major problem. Modern frames are produced from a one piece box section, heat treated for strength and to keep weight to a minimum. Manufactures without sophisticated heat treatment equipment however, use welded fabrications which can be heavy and impose high forces on the rear of the tractor. A plough frame has to with stand very high twisting forces, especially when in transport mode and therefore has to be flexible to absorb the stresses and strains, yet rigid enough to maintain alignment accuracy.
The majority of early reversible ploughs had furrow widths fixed at 12 or 14in. in size. To improve output efficiency and plough versatility, furrows had to get wider and capable of being adjusted. This was not only to suit soil conditions, but to help reduce manufacture and dealer stocking levels. In the late 70's, plough frames were being introduced with wedges, holes and parallel linkage to enable the furrow width to be easily changed. As today, output was the key factor and 16" ploughs began to appear from Europe. Many times we were told by our seniors, 'you can not plough wider than 14in. Well, they have been proved wrong, because ploughs are now capable of operating at over 20in. This was not possible without the development of a new mouldboard shape to allow for wider furrows and faster operation. With a new mouldboard design, the patented Vari-Width system soon became popular because of its high output efficiency - more acres a day.
85cm (33.5in.) interbody and 70cm (27.5in.) underbeam clearances or above is generally accepted as adequate for UK surface trash conditions, yet thirty years ago we were using ploughs with as little as 20in. between bodies and 17in. underbeam. These early ploughs just would not perform at today's speeds in excess of 6mph and with large amounts of surface residue left over after harvest.
No more rigid plough legs as in the past. All the latest ploughs can be equipped with either shear bolts or auto-reset systems to protect against rocks and occasional obstructions. A must now because we are using very high horse powered tractors at faster operating speeds. Not forgetting, ploughs are longer and heavier today and do not 'jump' over obstacles as in the past - if you were lucky! Modern steels play an important part too, because they have greater resistance to wear and can operate under tougher conditions and at higher speeds without breaking. The old chilled cast iron shares are items of the past and gone forever.
This is a very short account of our past and we all know life does not stand still. Development will always continue into eternity, with man trying to find the ultimate solution in food production for his survival. Modern plastics or similar, together with electronics and automatic machinery that think as they operate will be our future. What is revolutionary today will inevitably be overtaken by science tomorrow. Despite what the critics may say, we can rest assured, the plough is here to stay.