Agricultural Machinery and

AGRICULTURAL MACHINERY AND At the dawn of history we find man practising the most elementary method of modifying soil conditions. He broke up the surface and prepared a seed bed, using for this purpose the most primitive of all cultivating devices, a digging implement in nature like a hoe. The seed was sown by hand and the husbandman either drove his domesticated animals over the land to cover the seed and consolidate the ground, or used a form of harrow or sim ilar implement or a bundle of twigs for the purpose. In early times the pnncipal crops were cereals or pulse and a fibre crop- flax. Harvesting was performed by means of a sickle, an early example of which, found in the Fayum in Egypt, consists of a wooden rod fitted with flint blades; metal was employed later, and a bronze sickle of about i000 B.C. is the counterpart of the modern sickle. The crops were carried to a threshing floor where the grain was trodden out by animals, crushed out by sledges or beaten out with flails. The corn was winnowed by casting it through the air with a spade or shovel and fanning or allowing the wind to sepa rate the heavy grain from the lighter husks.

The greatest mechanical advance during these early days of agri culture was the evolution of the plough from the primitive hoe. This transition is very clearly seen in ancient Egypt. The advent of the plough enabled man to supplement his labour by animal power and is one of the great landmarks of agricultural progress. Mesopotamia furnishes evidence of the use of a primitive com bined plough and drill, but it is doubtful whether the implement had any advantage over the customary methods ; at all events it was lost to later civilization. By Roman times a primitive ridging plough had been evolved by the use of a device resembling the modern double mould board. When the single mould board was developed or when wheels were added to the plough is not defi nitely known. Pliny, the elder, who lived in the first century, men tions a wheel plough, but the use of such ploughs did not become general until much later. Pliny also reported the use in Gaul of a harvesting device, which was pushed by oxen, for heading or strip ping the grain. But ancient civilizations did not make any con siderable progress on the mechanical side of agriculture and such mechanical contrivances as were used disappeared with the bar barian invasions.

During the middle ages and until after the Renaissance the variety of implements at the disposal of the husbandman had ad vanced but little, though the roller was known but was not em ployed generally in agriculture. It must not, however, be supposed that there was absolute sameness or an uncritical acceptance of the implements handed down from previous generations. Fitz herbert's Book of Husbandry, printed in England in 1523, men tions the different types of plough used in different districts and attempts to give reasons for the differences in design. Fitz herbert appears to have realized that the design of the plough must be modified to reduce the draught in different kinds of soil. Hand tools had been perfected and often represent, even in small details, the hand tools in use to-day. By the year i 600 more elab orate implements were coming into use, and more than one book published in England about this time deals with the "new and admirable art of setting of corn." About 173o Jethro Tull (q.v.), who is renowned for his horse-hoeing husbandry, developed a seed drill which was really workable, although its general adoption was hampered by Tull's advocacy of impracticable methods of cultiva tion.

In the eighteenth century there was a conscious and organized attempt to improve agricultural implements, and in England the Society of Arts, which had been founded in 17S4, encouraged the movement by the offer of premiums. Ploughing matches were held in many parts of the country and attracted general support from farmers and their men. There were also competitions in the use of drills and horse-hoes. New methods and inventions were being applied to most farming operations, and new conditions were being created favourable for the great advance which followed.

The Steam Engine.

By the 19th century such a complexity had been introduced as to justify the use of the term "agricultural machinery." In agriculture, as in the manufacturing industry, the use first of water-power and then of steam had immensely stimu lated the invention of machinery supplementing or replacing man ual labour. A workable threshing machine was invented late in the i8th century and was gradually coming into use early in the i 9th ; it was driven by water or wind power, sometimes by horse labour, and later by steam. But it was not until the '3os of the i 9th century that steam began to be applied at all extensively to agriculture. A system was then introduced whereby one or two engines were employed to draw multi-furrowed ploughs, by means of cables, backwards and forwards across the field, and after a good deal of experimentation the established system of steam ploughing with a double-engined cable set was devised in the fif ties. Heavy implements such as the cultivator and mole plough were later added to the equipment of steam tackle; mechanical threshing became popular and steam-engines were also used to some extent to drive barn machinery. Nevertheless, for the most part the development of agricultural machinery upon the farm owes little directly to steam. The mowing machine and the self binder, the tedder and swath-turner, the drill, the potato-digger, chaff-cutters and root-cutters, all have been developed in the first instance for horse or manual labour, though doubtless receiving a fresh stimulus from the general mechanization of industry ap plied to the farm and the still greater stimulus, in Britain as in America, arising from a shortage of cheap labour.

The Internal-combustion Engine.

In still more recent times an important practical contribution to the mechanization of the farm came from the discovery of the internal-combustion en gine. Used first of all to drive stationary machinery, as chaff cutters, root-cutters and corn-mills in the barn, in the second decade of the loth century the internal-combustion engine also made headway as a source of power for field operations. Steam engines, though widely used for traction on the road, suffered the disadvantage of being heavy for use on the land for the direct haulage of machinery and implements; it was not until the inter nal-combustion engine had been perfected that agricultural trac tors made their appearance in any number.

This type of tractor has now an established position on the farm on both sides of the Atlantic ; it supplies power for ploughing, cultivating and harvesting; it can both drive and haul the thresh ing-machine, and there can be no doubt it contains the promise of still further usefulness. The practice of mole-draining, for ex ample, has been greatly stimulated not only in Britain but on the Continent of Europe by the invention of mole-ploughs that can be hauled by a suitable agricultural tractor. The cost of the work is substantially less than when performed by steam tackle and is far more expeditious than when performed by horses. The tractor has also rendered it easier for the farmer to undertake deep ploughing and subsoiling, which are very important for growing a crop such as sugar beet. Subsoiling had been looked on with dis favour because of the heavy strain imposed upon the teams and, when carried out at all, had been left in great measure to steam tackle. The application of the internal combustion engine has also enabled designers to produce machines of more moderate size and weight than f ormerly.

Another direction in which the internal-combustion engine is likely to prove its usefulness is in rotary tillage. This is a system which may ultimately replace ploughing and subsequent cultivat ing by a single operation. It has been advocated since the first half of the 19th century, and many attempts have been made to devise an effective machine, the best known being the Darby digger which inverted the soil by an action somewhat resembling that of the spade. The most promising machines make use of re volving tines for disintegrating the soil and the tines revolve in such a way as to assist the propulsion of the machine. The advan tages and limitations of rotary tillage have still to be tried out. In a climate like that of Great Britain the combined effects of autumn or winter ploughing and frost may not be attainable by rotary tillage. Given suitable soil and climatic conditions, how ever, the potential advantages of preparing a seed-bed at one oper ation and on a considerable scale are obvious.

The internal-combustion engine thus enables operations to be efficiently performed which were beyond the resources of the or dinary farmer, or which were little more than ideas in the days of steam and horse labour. But this is not its only or perhaps its chief usefulness. It enables operations to be performed far more speedily with an equal labour force and is therefore an ally to the farmer in his struggle against adverse weather conditions. Obvi ously, if five or six acres can be ploughed in a day by a tractor where formerly a plough-team accounted for less than one acre, another factor than the unit cost of the ploughing, namely, that of speed or of the time conditions, has entered into the operations. Again, if 20 acres can be reaped in a day as against ten or 12 acres by two teams of horses, the same factor enters. Full advan tage, however, cannot be taken of the tractor when the implements and machines used with it are those designed and constructed for horse haulage; to obtain the full benefit implements expressly designed for tractor work must be employed.

In the cable system of ploughing and cultivating, the internal combustion engine appears likely also to replace steam. The ease of handling oil fuel as compared with the difficulties often attend ing the transport of water and coal or wood must, it would seem, in the long run prove the decisive factor. The advent of the pro ducer-gas plant for use with tractors and lorries is also likely to extend the use of the internal-combustion engine in countries where liquid fuel is scarce and suitable materials for producing gas are available. The possibilities of the production of power alcohol on a commercial scale must also be borne in mind when considering the future sources of energy for the farmer.

Electricity.

But a still newer source of power which has made its appearance upon the farm is electricity. Owing to the shortage of coal and oil fuel during the War period, a stimulus was given to the exploitation of water-power and electricity undertakings. Al though employed at first principally for lighting, electricity, when it is available at low cost relatively to other forms of power, is gradually coming into use for driving stationary machinery on the farm. Its further use for cultivating the land has scarcely gone beyond the experimental stage as yet, although systems of cable ploughing in which electric motors are employed are actually in operation in several European countries. The principal difficulty is the transmission of current to every part of the farm where it may be needed, since equipment with transmission lines may involve serious expense.

Other Mechanical Progress.

The gradual mechanisation of the farm is apparent, however, not only in those branches of agri culture and methods of operations which are of long standing. As new crops are introduced or old crops revived, mechanical means are devised to deal with them. Each crop indeed demands its appropriate machines. A crop such as sugar beet, when introduced into a country where labour is dear, requires effective mechanical means for dealing with it at all its stages, but particularly for har vesting—the most arduous of the whole cycle of operations ; con sequently it is necessary to devise mechanical lifters and toppers as substitutes for the hand labour employed in countries where wages are low. Similarly with the flax crop ; its revival in Britain has led to concentration on the problems of harvesting and the preparation of the fibre for the spinner. Machines for pulling the crop and for scutching (or dressing) the straw have been devised, and new mechanical processes have been advocated to supersede entirely the traditional hand methods.

Classification of Machinery.

Agricultural implements and machines are now very numerous and very diversified and may be considered under five main groups, namely : (I) prime-movers, i.e., engines of all kinds, tractors, water-wheels, windmills, etc. ; (2) cultivating machinery, including ploughs of all kinds, rotary tillers, harrows, hoes, scarifiers, rollers, manure distributors, drills, mole ploughs, etc. ; (3) harvesting machinery, including mowers, rakes, swath-turners, tedders, reapers, self-binders, threshing machines, elevators, potato lifters, beet toppers and lifters, crop drying plants, etc.; (4) stationary or barn machinery, including such food-preparing machines as cake-breakers, chaff cutters, grinding and crushing mills, root-cutters, etc.; (5) dairy machinery, includ ing milking machines, separators, churns, butter workers, steriliz ing and bottling machines, etc. In addition, there are a number of miscellaneous machines, including sprayers, sheep-shearing and horse-clipping machines.

Economics of Machinery.

From the development of such mechanical devices it does not, however, follow that every farmer can economically use machinery for all possible purposes. With his small acreage of grass and cereals the smallholder, for example, would probably not feel justified in purchasing any harvesting machinery, except a horse rake and a combined mower and reaper, whilst the farmer with a holding of 30o acres or so of mixed arable and pasture land would find it necessary to have a complete outfit of cultivating, harvesting and stationary machinery, besides many dairy appliances if milk production were also an important part of his enterprise. In suitable • circumstances he would probably also find it desirable to supplement horse labour by one or more trac tors and would probably thresh his own produce. But on very large arable farms, such as extend in some parts of the world to several thousands of acres, the range of agricultural machinery would include cable sets and possibly even trenching machines for excavating and grading drains and ditches.

The economic use of machinery in agriculture is dependent on a number of factors which vary from country to country, from district to district, and from one type and size of farm to another, but there is one principle common to all cases : a machine must do sufficient work to repay its capital outlay and working costs over a reasonable period. To meet this requirement the minimum amount of work must be available before any particular machine can be employed economically. The potato crop furnishes an ex cellent illustration. The cheapest way to lift a small plot of pota toes is by hand forking ; the lifting of an area of an acre or so will repay the cost of a simple potato plough ; while a larger area will justify the purchase of a potato-lifting machine. But the use of machinery depends also on other factors besides cheapness in com parison with other methods. Speed of work and ability to take ad vantage of favourable weather are factors which may influence considerably the adoption of mechanical devices, although it may be difficult for any system of farm costings to take cognisance of these advantages. Emphasis must at present be laid on the paucity of accurate knowledge regarding the cost of farming operations in general, though efforts have in recent years been made in Europe and America to analyse farm costs and to stimulate the adoption by farmers of some simplified system of cost- accounting. The comparative cost of individual operations or units of work is, how ever, not sufficient; the problem from the farmer's point of view is rather the production of food units at a minimum cost, and the marketing of them either directly or by feeding to stock in such a way as to obtain a maximum return on the capital outlay in volved.

Social Effects of Machinery.

It is sometimes supposed that the introduction of machinery has led to rural depopulation and will intensify it. But even in older countries machinery has more often than not been introduced because a labour supply of a par ticular kind has failed; for example, the falling-off of casual and migrant labour at harvest time due to a number of social causes has encouraged the widespread adoption of the self-binder. In newer countries the introduction of machinery has had the effect of populating waste areas, for the vast tracts of new land in the United States, Australia, Canada, etc., could not be farmed in present circumstances without the aid of machinery; the alter native would be timber production or stock raising.

The use of machinery also requires skilled workers, and the more widespread the use of machinery becomes in agriculture the more highly skilled will be the farmworkers. The mechanisation of agri culture also means that a higher wage can be paid because the unit of production is enlarged, but as a corollary it also indicates larger farms or groups of small farms worked as one economic unit. The alternative is a system of peasant holdings with primitive methods; but the Western world is steadily moving away from the social con ditions which made such a system possible.

See CULTIVATING MACHINERY ; DAIRY MACHINERY ; HARVEST ING MACHINERY; STATIONARY (BARN) MACHINERY. Also such articles as SHEEP SHEARING MACHINES ; TRACTORS ; DRAINAGE, etc.

BIBLIOGRAPHY.—J. C. Loudon, Encyclopaedia of Agriculture (1825) ; Bibliography.—J. C. Loudon, Encyclopaedia of Agriculture (1825) ; L. Rau, Geschichte des Pfluges (Heidelberg, 1845) ; J. Slight and R. Scott Burn (ed. Henry Stephens), The Book of Farm Implements and Machines (Edinburgh, 1858) ; Max Ringelmann, Essai sur l'Histoire du genie rural (1903) ; J. B. Davidson and L. W. Chase, Farm Ma chinery and Farm Motors (1908), a text-book of general application throughout the world, but especially applicable to America, contains an excellent bibliography ; R. Braungart, Die Urheimat der Land wirtschaft aller indogermanischen Volker (Heidelberg, 1912) ; J. R. Bond, Farm Implements and Machinery (1923), a text-book dealing with machinery used in Great Britain, contains no bibliography ; Scottish Journal of Agriculture, vols. viii. and ix. (1925-26), Prof. J. A. S. Watson, "Farm Implements in Scotland, Historical Notes"; Lord Ernle (R. E. Prothero), English Farming Past and Present (4th ed. 1927) . J. 0.; H. G. R.)