Tillage (American English), or cultivation (UK) is the agricultural preparation of the soil to receive seeds. Primary tillage loosens the soil and mixes in fertilizer and/or plant material, resulting in soil with a rough texture. Secondary tillage produces finer soil and sometimes shapes the rows. It can be done by a using various combinations of equipment: plow, disk plow, harrow, dibble, hoe, rotary tillers, subsoiler, ridge or bed forming tillers, roller.
Tillage can also mean the land that is tilled.
Modern agriculture has greatly reduced the use of tillage for weed control. Through the use of herbicides and no-till planters crops can be grown for several years without any tillage. This practice has greatly reduced soil erosion and improved the quality of the environment by reducing the total tonnage of soil that is washed into streams and blown into the air to produce dust.
Tillage and its effects are now a modern agricultural science carefully researched by universities across the planet which have disproven many of the ideas put forth by the passages quoted below.
The following text is taken from the Household Cyclopedia of 1881:
Tillage is an operation whereby the soil is either cleared from noxious weeds, or prepared for receiving the seeds of plants cultivated by the husbandman. When this operation is neglected, or even partially executed. the soil becomes foul, barren, and unproductive; hence, upon arable farms, tillage forms the prominent branch of work; and, according to the perfection or imperfection with which it is executed, the crops of the husbandman, whether of corn or grass, are in a great measure regulated.
Tillage, in the early ages, was performed by hand labor; but, in modern times, the plough has been the universal instrument used for executing this necessary and important branch of rural work. In no other way can large fields be turned over because the expense of digging with the spade, the only other method of turning over the ground, would much exceed any profit that can be reaped.
Stones lying above or below the surface are the most formidable obstruction to perfect tillage. On stony ground, the work is not only imperfectly executed, but in many cases the implement is broken to pieces, and a considerable portion of time lost before it is repaired and put in order. The removal of stones, therefore, especially of such as are below the surface, ought to be a primary object with every agriculturist; because a neglect of this kind may afterwards occasion him considerable loss and inconvenience.
To drain the ground, in other words, to lay it dry, also facilitates tillage exceedingly; for ploughing cannot be performed with advantage where either the surface or subsoil is wet.
The only sure and certain way by which the soil is cleaned or rendered free of weeds, is by ploughing in the summer months, when the ground is dry, and when, by the influence of the sun and air, the weeds may be destroyed with facility. Seldom at any other period is the soil much benefitted by ploughing, unless so far as a seed-bed is thus procured for the succeeding crop; and though the situation or state of the ground, when these intermediate ploughings are bestowed, is of importance in judging of their utility, yet the radical process of summer fallow cannot, by any means, be altogether dispensed with. Though, if the winter and spring ploughings are executed under favorable circumstances, and plenty of manure is at hand, it may be delayed for a greater number of years than is otherwise practicable, if good husbandry is to be maintained.
Without summer fallow, or, which is the same thing, without working the ground in the summer months, perfect husbandry is unattainable on all heavy or cold soils, and upon every variety incumbent on a close or retentive bottom.
To keep his land clean will always be a principal object with every good farmer; for if this is neglected, in place of carrying rich crops of grain or grass, the ground will be exhausted by crops of weeds. Where land is foul, every operation of husbandry must be proportionately noneffective; and even the manures applied will, in a great measure, be lost.
The necessity of summer fallow depends greatly upon the nature and quality of the soil; as, upon some soils, a repetition of this practice is less frequently required than upon others. Wherever the soil is incumbent upon clay or till, it is more disposed to get foul, than when incumbent upon a dry gravelly bottom; besides, wet soils, from being ploughed in winter, contract a stiffness which lessens the pasture of artificial plants, and prevents them from receiving sufficient nourishment. When land of a dry gravelly bottom gets foul, it may easily be cleaned without a plain summer fallow; single crops, such as turnips, etc., may be substituted in its place, which, when drilled at proper intervals admit of being ploughed as often as necessary; whereas wet soils, which are naturally unfit for carrying such crops, must be cleaned and brought into good order by frequent ploughings and harrowings during the summer months.