Editing Plough (section)

==Specialist ploughs==
===Chisel plough===

[[File:JDTractor chisel-plough.jpg|thumb|A chisel plough; the ploughing tines are at the rear, the refuse-cutting [[Coulter (agriculture)|coulters]] at the front.]]
The ''chisel plough'' is a common tool for deep tillage (prepared land) with limited soil disruption. Its main function is to loosen and aerate the soils, while leaving [[crop residue]] on top. This plough can be used to reduce the effects of soil compaction and to help break up [[plowpan|ploughpan]] and [[hardpan]]. Unlike many other ploughs, the chisel will not invert or turn the soil. This feature has made it a useful addition to [[no-till farming|no-till]] and low-till farming practices that attempt to maximise the erosion-preventing benefits of keeping organic matter and farming residues present on the soil surface throughout the year. Thus the chisel plough is considered by some{{who|date=December 2012}} to be more [[Sustainable agriculture|sustainable]] than other types of plough, such as the [[#Mould-board ploughing|mould-board plough]].

[[File:Bigham Brother Tomato Tiller.JPG|thumb|Tomato tiller]]
Chisel ploughs are becoming more popular as a primary tillage tool in row-crop farming areas. Basically the chisel plough is a heavy-duty field cultivator intended to operate at depths from {{convert|15|cm|abbr=on}} to as much as {{convert|46|cm|abbr=on}}. However some models may run much deeper.{{clarify|subsoiler|date=May 2021}} Each individual plough or shank is typically set from {{convert|9|inch|abbr=on|order=flip}} to {{convert|14|inch|abbr=on|order=flip}} apart. Such a plough can meet significant soil drag: a [[tractor]] of sufficient power and traction is required. When ploughing with a chisel plough, {{convert|10|–|20|hp|kW}} per shank is required, depending on depth.{{citation needed|date=May 2016}}

Pull-type chisel ploughs are made in working widths from about {{convert|2.5|m}} up to {{convert|13.7|m}}. They are tractor-mounted, and working depth is hydraulically controlled. Those more than about {{convert|4|m}} wide may be equipped with folding wings to reduce transport width. Wider machines may have the wings supported by individual wheels and hinge joints to allow flexing of the machine over uneven ground. The wider models usually have a wheel each side to control working depth. Three-point hitch-mounted units are made in widths from about {{convert|1.5|to|9|m}}.

[[Cultivator]]s are often similar in form to chisel ploughs, but their goals are different. Cultivator teeth work near the surface, usually for weed control, whereas chisel plough shanks work deep under the surface; therefore, cultivation takes much less power per shank than does chisel ploughing.

===Country plough===
The country plough is a slanted plough.<ref>{{cite web |url=http://www.hillagric.ac.in/edu/coa/agengg/lecture/243/Lecture%2011%20Primary%20Tillage.pdf |title=Tillage and its Implements |website=[[Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya|Himachal Pradesh Agriculture University, Palampur]] |access-date=11 January 2022 |archive-url=https://web.archive.org/web/20191104195403/http://www.hillagric.ac.in/edu/coa/agengg/lecture/243/Lecture%2011%20Primary%20Tillage.pdf |archive-date=4 November 2019 |url-status=dead}}</ref> The most common plough in India,<ref>{{Cite web|url=http://ecoursesonline.iasri.res.in/mod/page/view.php?id=56836|title = Fodder and Grass: Country plough}}</ref> it is recommended for crops like groundnut after the use of a tractor.<ref>{{Cite web|url=http://www.agritech.tnau.ac.in/agriculture/oilseeds_groundnut.html|archive-url = https://web.archive.org/web/20190724174534/http://www.agritech.tnau.ac.in/agriculture/oilseeds_groundnut.html|archive-date = 24 July 2019|title = Agriculture :: Oil Seeds :: Groundnut}}</ref>

===Ridging plough===
A ridging plough is used for crops such as [[potato]]es or [[scallion]]s grown buried in ridges of soil, using a technique called ''ridging'' or ''[[hilling]]''. A ridging plough has two back-to-back mould boards cutting a deep furrow on each pass with high ridges either side. The same plough may be used to split the ridges to harvest the crop.

===Scots hand plough===
This variety of ridge plough is notable for having a blade pointing towards the operator. It is used solely by human effort rather than with animal or machine assistance and pulled backwards by the operator, requiring great physical effort. It is particularly used for second breaking of ground and for potato planting. It is found in Shetland, some western crofts, and more rarely Central Scotland, typically on holdings too small or poor to merit the use of animals.

===Ice plough===

[[File:Cutting ice in Norway using an ice plough c.1910.jpg|thumb|Cutting ice in Norway using an ice plough {{circa|1910}}]]

Functionally operating as a saw, but pulled as a plough, this device was created in the 19th century and was mainly used in Scandinavia, as part of the ice export industry, creating blocks of ice to ship to Great Britain.<ref>Case display notes, Canal and Ice Museum, London</ref>

===Mole plough===
The mole plough allows under-drainage to be installed without trenches, or breaks up the deep impermeable soil layers that impede it. It is a deep plough with a torpedo or wedge-shaped tip and a narrow blade connecting it to the body. When dragged over ground, it leaves a channel deep under it that acts as a drain. Modern mole ploughs may also bury a flexible perforated plastic drain pipe as they go, making a more permanent drain{{snd}}or may be used to lay pipes for water supply or other purposes. Similar machines, so-called [[pipe-and-cable-laying plough]]s, are even used under the sea for laying cables or for preparing the earth for [[side-scan sonar]] in a process used in [[oil exploration]].

Compacting a tennis ball-sized sample from moling depth by hand, then pushing a pencil through is a simple check to find if the subsoil is in the right condition for mole ploughing. If the hole stays intact without splitting the ball, the soil is in ideal condition for the mole plough.

Heavy land requires draining to reduce its water content to a level efficient for plant growth. Heavy soils usually have a system of permanent drains, using perforated plastic or clay pipes that discharge into a ditch. The small tunnels (mole drains) that mole ploughs form lie at a depth of up to {{convert|950|mm|abbr=on}} at an angle to the pipe drains. Water from the mole drains seeps into the pipes and runs along them into a ditch.

Mole ploughs are usually trailed and pulled by a crawler tractor, but lighter models for use on the three-point linkage of powerful four-wheel drive tractors are also made. A mole plough has a strong frame that slides along the ground when the machine is at work. A heavy leg, similar to a sub-soiler leg, is attached to the frame and a circular section with a larger diameter expander on a flexible link is bolted to the leg. The bullet-shaped share forms a tunnel in the soil about {{convert|75|mm|abbr=on}} diameter and the expander presses the soil outwards to form a long-lasting drainage channel.

===Para-plough===
The para-plough, or paraplow, loosens compacted soil layers 3 to 4 dm (12 to 16 inches) deep while maintaining high surface residue levels.<ref>{{Cite FTP |url=ftp://ftp-fc.sc.egov.usda.gov/IA/intranet/Tillage.pdf |server=[[Natural Resources Conservation Service]] |url-status=dead |title=Tillage Equipment |access-date=11 June 2012}}</ref> It is primary tillage implement for deep ploughing without inversion.

===Spade plough===
The spade plough is designed to cut the soil and turn it on its side, minimising damage to earthworms, soil microorganism and fungi. This increases the sustainability and long-term fertility of the soil.

===Switch plough===
Using a bar with square shares mounted perpendicularly and a pivot point to change the bar's angle, the switch plough allows ploughing in either direction. It is best in previously-worked soils, as the ploughshares are designed more to turn the soil over than for deep tillage. At the headland, the operator pivots the bar (and so the ploughshares) to turn the soil to the opposite side of the direction of travel. Switch ploughs are usually lighter than roll-over ploughs, requiring less horsepower to operate.