Lister(redirected from middlebreaker)
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agricultural implement used to cut furrows in and turn up the soil, preparing it for planting. The plow is generally considered the most important tillage tool.
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a machine for making bed ridges. It is used to cultivate vegetables on soils with high groundwater levels. It operates in a unit with a vegetable planter and fertilizer distributor.
The working parts of listers made in the USSR are two plow bottoms with graders and three small harrows. Four fertilizer distributors and four injection knives are mounted on the cultivator to introduce inorganic fertilizers. A single pass of the body of the plow bottom forms one ridge and two half-ridges; the graders level the surface of the ridges, and the small harrows loosen the soil. In the second pass, a second, newly formed half-ridge is added to one half-ridge. The ridges thus formed are 20 cm high and up to 90 cm wide. The distance between the axes of adjacent ridges is 135–140 cm. The productivity of a two-bottom lister is 1.4–1.7 hectares per hr.
In the northwestern zone of the USSR a combined unit is used that consists of a lister along with a sowing machine, a ridger-sowing machine, and a cultivator. At the same time as it makes the ridges, this unit loosens and packs the soil, sows the vegetable crops, and inserts inorganic fertilizers.